Engine Controls - Self-Diagnostics - 4.0L: Diagnosis Oldsmobile Aurora II

ON-BOARD DIAGNOSTICS

The Malfunction Indicator Light (MIL) is located on right side of instrument cluster and is displayed as an engine icon. The MIL is controlled by the Powertrain Control Module (PCM) and is used to indicate that the PCM has detected a problem that affects vehicle emissions and a Diagnostic Trouble Code (DTC) is present. When ignition is first turned on, MIL should come on and remain on until engine is started to verify bulb and circuit operation. If MIL does not illuminate at all, diagnose MIL circuits. See MALFUNCTION INDICATOR LIGHT INOPERATIVE under SYSTEM TESTS. The PCM is programmed with test routines that check the operation of the various systems that the PCM controls. Some tests check the internal functions of the PCM. Some tests are run continuously while other tests run only under specific conditions (referred to as code enable criteria). When the vehicle is operating within the conditions for running a particular test, the PCM checks certain parameters and determines whether or not the values are within an expected range. When the conditions for setting the DTC are met, the PCM will store a DTC and, if code is emission related, illuminate the MIL. Some DTCs alert the driver via a message. See CODE TYPES . The PCM also saves data and input parameters when most DTCs are set. This data is stored in FREEZE FRAME and/or FAILURE RECORDS. See FREEZE FRAME and FAILURE RECORDS .

DIAGNOSTIC PROCEDURE

Diagnosis of computerized engine control system should be performed in the following order

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. Powertrain diagnostic system check must be performed before using specific Diagnostic Trouble Code (DTC) testing procedure. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If no DTCs are present and a driveability problem exists, diagnose by symptom. See appropriate TROUBLE SHOOTING - NO CODES article. After repairs are made, clear DTCs, verify vehicle will enter "closed loop" operation and ensure DTC does not reset.

RETRIEVING DIAGNOSTIC TROUBLE CODES

Diagnostic Trouble Codes (DTC) are retrieved using a Tech 2 scan tool, or other OBD-II compatible scan tool connected to Data Link Connector (DLC). (Scheme 1) DLC is located below left side of instrument panel. To retrieve DTCs, powertrain diagnostic system check must be performed. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM CHECKS.

Scheme 1

CLEARING DIAGNOSTIC TROUBLE CODES

Note. Manufacturer does not recommend disconnecting the battery to clear Powertrain Control Module (PCM) memory. Disconnecting battery may or may not clear PCM memory, but other memory system memories will be cleared. On many OBD-II systems, PCM will retain memory for an extended period of time even with battery disconnected.

Using Scan Tool

Using scan tool manufacturer's instructions, clear DTCs. Freeze frame and failure record data will also be cleared. PCM adaptive learning and system monitors will only be cleared for system which had a stored DTC.

Self-Erasure

After 3 consecutive ignition cycles that the diagnostic runs and does not fail, PCM will turn off the malfunction indicator light. At that time, the PCM will automatically switch to a warm-up cycle counter. A warm-up cycle occurs when engine temperature increases 22°F from start-up and reaches a minimum of 160°F (71°C). The PCM will clear DTCs from memory after 40 consecutive warm-up cycles if the recent malfunction does not reoccur in that time.

SCAN TOOL USAGE

Note. OBD-II vehicles have options available in the scan tool DTC mode to display enhanced information available. However, to fully utilize information and procedures requires the use of a Tech 2 scan tool. See scan tool operator's manual for additional information.

Scan Tool Displays

When the scan tool displays a Diagnostic Trouble Code (DTC), the status of the DTC is also displayed. The following are Tech 2 scan tool sub-menus in the DTC INFO and SPECIFIC DTC modes. DTC statuses will be indicated only when they apply to the DTC that is set.

1. FAIL THIS IGN. This selection indicates that this DTC failed during the present ignition cycle.
2. LAST TEST FAIL This selection indicates that this DTC failed the last time the test ran. If type "A" or "B" DTCs are displayed, the last test may have ran during the previous ignition cycle. For type "C" DTCs, the last failure must have occurred during the current ignition cycle to be displayed as LAST TEST FAIL.
3. MIL REQUEST This selection indicates that this DTC is currently requesting MIL illumination. This selection will report type "B" DTCs only after MIL illumination has been requested (failed twice).
4. TEST FAIL SCC Test Fail Since Code Clear (SCC) indicates that this DTC is active since the last time DTCs were cleared.
5. HISTORY This selection indicates that this DTC is stored in the PCM history memory. Type "B" DTCs will not appear in history until they have been requested by the MIL (failed twice). History will display all type "A" and type "B" DTCs that have the MIL illuminated and have failed within the last 40 warm-up cycles. It will also display type "C" DTCs that have failed within the 40 warm-up cycles.
6. NOT RUN SCC Not Run Since Code Clear (SCC) will display DTCs that have not run since DTCs were last cleared. Since any displayed DTCs have not run, their condition (passing or failing) is unknown.

AIR CONDITIONING DIAGNOSTIC SYSTEM CHECK

1. Connect scan tool to Data Link Connector (DLC). DLC is located below left side of instrument panel, on hood release bracket. If scan tool powers up, go to next step. If scan tool does not power up, perform «SCAN TOOL DOES NOT POWER UP»(ref-121492-S15706837922001083100000) under SYSTEM TESTS.
2. Turn ignition on. Using scan tool, attempt to communicate with Driver Door Module (DDM), Powertrain Control Module (PCM), Instrument Panel Integration Module (IPM) and Dash Integration Module (DIM). If scan tool communicates with DDM, PCM, IPM and PCM, go to next step. If scan tool does not communicate with DDM, PCM, IPM and DIM, diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Using scan tool, select DDM, PCM, IPM and DIM, display DTCs function. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, repair air conditioning system by symptom. See AUTOMATIC A/C-HEATER SYSTEMS - AURORA article in AIR CONDITIONING & HEATING.
4. If scan tool does not display any DTCs which begin with "U", go to next step. If scan tool displays any DTCs which begin with "U", diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
5. If scan tool does not display DTC B10XX, go to next step. If scan tool displays DTC B10XX (except B1000), perform appropriate test in accordance with DTC retrieved. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
6. If scan tool displays DTC B1327, repair charging system as necessary. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEM. If scan tool does not display DTC B1327, go to next step.
7. If scan tool displays DTC P0530, P0533, P1536, P1545 or P1546, repair air conditioning system as necessary. See AUTOMATIC A/C-HEATER SYSTEMS - AURORA article in AIR CONDITIONING & HEATING. If scan tool displays any other DTCS, diagnose DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

ENGINE COOLING DIAGNOSTIC SYSTEM CHECK

1. Connect scan tool to Data Link Connector (DLC). (Scheme 1) DLC is located below left side of instrument panel. Turn ignition on. If scan tool powers up, go to next step. If scan tool does not power up, see «SCAN TOOL DOES NOT POWER UP»(ref-121492-S15706837922001083100000) under SYSTEM TESTS.
2. Using scan tool, attempt to communicate with Instrument Panel Cluster (IPC), Dash Integration Module (DIM) and Powertrain Control Module (PCM). If scan tool communicates with IPC, DIM and PCM, go to next step. If scan tool does not communicate with IPC, DIM and PCM, diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Using scan tool, select IPC, DIM and PCM display DTCs function. If scan tool displays any DTCs, go to next step. If scan tool does not display DTCs, repair engine cooling system by symptom. See ELECTRIC COOLING FANS - CARS article in ENGINE COOLING.
4. If scan tool displays any DTCs that begin with "U", diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any DTCs that begin with "U", go to next step.
5. If scan tool displays DTC P0480, P0481 or P1258, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If scan tool displays any DTCs that begin with "B", repair DTCs as necessary. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.

ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK

1. Ensure battery is correct battery for vehicle. Ensure battery is fully charged and in good working condition. Replace battery as necessary. If battery is okay, go to next step.
2. Connect scan tool, if not already connected. Turn ignition on. If scan tool powers up, go to next step. If scan tool does not power up, see «SCAN TOOL DOES NOT POWER UP»(ref-121492-S15706837922001083100000) under SYSTEM TESTS.
3. Using scan tool, attempt to communicate with Instrument Panel Cluster (IPC), Dash Integration Module (DIM) and Powertrain Control Module (PCM). If scan tool communicates with IPC, DIM and PCM, go to next step. If scan tool does not communicate with IPC, DIM and PCM, diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
4. Using scan tool, select IPC, DIM and PCM display DTCs function. If scan tool displays any DTCs, go to next step. If scan tool does not display DTCs, repair charging system by symptom. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
5. If scan tool displays any DTCs that begin with "U", diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any DTCs that begin with "U", go to next step.
6. If scan tool displays DTC B1000, B1007 or B1009, repair as necessary. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display DTC B1000, B1007 or B1009, repair other DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

POWERTRAIN DIAGNOSTIC SYSTEM CHECK

Note. Check for applicable technical service bulletins before proceeding. Do not perform the following procedure if no driveability conditions exist, unless directed here from another procedure. Do not turn ignition off during the following procedure or clear DTCs unless instructed to do so.

1. If a condition exists with starting system, perform engine electrical diagnostic system check. See «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08828289192001110500000) . Ensure battery is fully charged and cables are clean and tight. Ensure Powertrain Control Module (PCM) grounds are clean, tight, and in proper location. See WIRING DIAGRAMS. PCM is located in engine compartment, next to air filter housing. Install scan tool. If scan tool powers up, go to next step. If scan tool does not power up, see «SCAN TOOL DOES NOT POWER UP»(ref-121492-S15706837922001083100000) under SYSTEM TESTS.
2. Turn ignition on. Attempt to establish communication with PCM, Electronic Brake Control Module (EBCM) and Vehicle Theft Deterrent (VTD) module. If scan tool communicates with all control modules, go to next step. If scan tool does not communicate with all control modules, diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Attempt to start engine. If engine starts and idles, go to next step. If engine does not start and idle, diagnose engine cranks, but does not start. See NO-START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
4. Using scan tool, select DTC display function for PCM, EBCM and VTD. If any DTCs are present, record DTCs, which module set the DTC and failure record for DTC. Go to next step. If no DTCs are present, go to step 8 .
5. If scan tool displays any DTCs that begin with "U", diagnose communication problem. See SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE under SYSTEM TESTS in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If scan tool does not display any DTCs that begin with "U", go to next step.
6. If scan tool displays DTC P0601, P0602, P0603, P0604, P0606 or P1621, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not display DTC P0601, P0602, P0603, P0604, P0606 or P1621, go to next step.
7. If scan tool displays DTC P0560, P0562, P0563, P0621 or P0622, see appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If scan tool does not display DTC P0562, P0563, P0621 or P0622, diagnose any other DTCs that are present. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .
8. If customer's concern is with the automatic transmission, see appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. If customer's concern is not with the automatic transmission, go to next step.
9. If customer's concern is MIL inoperative, diagnose MIL circuits. See «MALFUNCTION INDICATOR LIGHT INOPERATIVE»(ref-121492-S40557568752001082900000) under SYSTEM TESTS. If customer's concern is MIL always on, diagnose MIL circuits. See «MALFUNCTION INDICATOR LIGHT ALWAYS ON»(ref-121492-S29550970012001082900000) under SYSTEM TESTS. If customer's concern is a driveability problem, diagnose by symptom. See appropriate TROUBLE SHOOTING - NO CODES article.

Diagnostic Procedures

1. Perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. If DTC or driveability concern was repaired using powertrain diagnostic system check, go to step 3 . If no DTC or driveability concern was repaired using powertrain diagnostic system check, go to next step.
2. Check for applicable Technical Service Bulletins (TSB) for software updates that may prevent Inspection/Maintenance (I/M) readiness. Perform any reprogramming or repairs indicated by TSBs. If reprogramming or repair service was required, go to «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-121492-S20653314242001090400000) . If reprogramming or repair service was not required, go to next step.
3. Using scan tool, observe I/M system status display. If more than one test indicates a NO status, go to «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-121492-S20653314242001090400000) . If only one test indicates a NO status, perform appropriate I/M system set procedure for indicated system. See «INSPECTION/MAINTENANCE SYSTEM SET PROCEDURE INDEX»(ref-121492-S20340287372001100800000) table. INSPECTION/MAINTENANCE SYSTEM SET PROCEDURE INDEX System With NO Status Perform AIR System «INSPECTION/MAINTENANCE AIR SYSTEM SET PROCEDURE»(ref-121492-S22123085572001083100000) Catalyst System «INSPECTION/MAINTENANCE CATALYST SYSTEM SET PROCEDURE»(ref-121492-S09558755422001083100000) EGR System «INSPECTION/MAINTENANCE EXHAUST GAS RECIRCULATION SYSTEM SET PROCEDURE»(ref-121492-S40115242382001083100000) EVAP System «INSPECTION/MAINTENANCE EVAPORATIVE EMISSION SYSTEM SET PROCEDURE»(ref-121492-S12801490312001083100000) HO2S/O2S System «INSPECTION/MAINTENANCE HEATED OXYGEN SENSOR/OXYGEN SENSOR SYSTEM SET PROCEDURE»(ref-121492-S26119389432001083100000) HO2S Heater System «INSPECTION/MAINTENANCE HEATED OXYGEN SENSOR HEATER SYSTEM SET PROCEDURE»(ref-121492-S35159770122001083100000)

Diagnostic Aids

I/M system status display provides an indication of when control module has completed required tests. This does not necessarily mean that test has passed, only that test has run. If diagnostics fail, a DTC will indicate failure. If a failure indication is present for a DTC associated with one of the I/M regulated systems, it may prevent other required tests from running. I/M system status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Note. Before performing this procedure, read diagnostic aid information. See DIAGNOSTIC AIDS .

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) . NOTE: Whenever ignition is on, ignition voltage is supplied to Heated Oxygen Sensor (HO2S) heaters. After verifying enable criteria, turn ignition off for approximately 5 minutes to allow sensors to cool before continuing test. Once engine has been started, DO NOT turn engine off for remaining portion of procedure.
2. Program scan tool with vehicle information before ignition is turned on. Turn off all accessories, including A/C and blower fan. Set vehicle parking brake. Ensure transmission is in Park. Ensure vehicle meets conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S36644020242001100800000) . Start engine. Allow engine to idle. Allow engine to idle for 2 minutes. Go to next step.
3. Test drive vehicle. Ensure vehicle is accelerated at part throttle to 55 MPH. Drive vehicle at 55 MPH until engine reaches normal operating temperature. This may take 8-10 minutes depending on start-up coolant temperature. Continue test driving vehicle under these conditions for 6 minutes. Go to next step.
4. Reduce vehicle speed to 45 MPH, maintain this speed for one additional minute. Perform 4 decelerations of 25 seconds each from 45 MPH while maintaining the following criteria: Throttle is closed. No brake application. No manual downshift. Vehicle speed remains greater than 25 MPH. After each deceleration period, vehicle speed is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. Go to next step.
5. Accelerate vehicle at part throttle to 45-55 MPH. Maintain this speed for 2 minutes. Decelerate vehicle to zero MPH. Idle engine for 2 minutes while service brake is depressed and transmission is in Drive. Go to next step.
6. Using scan tool, observe I/M system status display. If all I/M system status indicators updated to YES, go to next step. If any I/M system status indicator did not update to YES, repeat procedure.
7. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate emission related DTCs, system is okay.

Rough road conditions may prevent some tests from running. Extreme high or low ambient temperatures may prevent tests such as HO2S heater and evaporative emission system from initiating. If step is interrupted before completion, perform remaining portion of test procedures. Any portion of test procedure that requires the engine at operating temperature may be repeated. This allows most diagnostics to run and the remaining tests can be performed using individual system set procedures.

If vehicle has recently run, start this procedure at step 3 . This will allow the tests that require engine at operating temperature to run. Using this method allows shorter cool down periods if the tests requiring a cold start do not initiate.

Scan tool can be used to monitor each I/M system status indicator. When all indicators for a test step have updated to YES, testing can move on to next step even if remaining portion of the test is not complete. For example, step 3 is designed to run EVAP, AIR, and HO2S tests. The procedure instructs technician to operate the vehicle in enable conditions for 6 minutes. If all 3 tests have updated to YES within 4 minutes, you do not need to continue with the enable conditions and testing can advance to the next step.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S02791917802001100800000) . Turn off all accessories, including A/C and blower fan. Start engine and allow it to idle for 2 minutes. Accelerate at part throttle to 45 MPH and maintain speed for 3 minutes or until or until I/M system status indicator updates to YES. Using scan tool, monitor I/M system status display. If AIR system status updates to YES, go to step 5 . If AIR system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0410, P1415 and P1416 have run. For those DTCs that have not run, operate vehicle under conditions to meet code enable criteria until DTC(s) runs. See CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Using scan tool, observe I/M system status display. If AIR system status updated to YES, go to next step. If AIR system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S37614867842001100800000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

The AIR pump generally operates once per ignition cycle, usually upon initial start-up before the engine goes into closed loop fuel control. Some systems will perform a passive diagnostic test at this time. The active diagnostic test is performed after the engine goes into closed loop fuel control. On vehicles that perform a passive test, the active test will only run if the passive test fails or is intermittent. The active test may not run if the passive test passes.

I/M system status does not indicate whether test has passed or failed, only that test has run. When all diagnostics for a specific system have run and passed, I/M system status will update to YES. If a test for a specific system has failed, I/M system status will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, DTC emission related DTC portion of the I/M system status display will indicate malfunction indicator light is requested. I/M system status also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Turn off all accessories, including A/C and blower fan. Start engine and allow it to idle. Accelerate at part throttle to 55 MPH and maintain speed for 5 minutes. Decelerate to a stop. Allow engine to idle for 2 minutes with service brake applied and transmission in Drive. Using scan tool, monitor I/M system status display. If CATALYST system status updates to YES, go to step 5 . If CATALYST system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, monitor DTC P0420. Operate vehicle within code enable criteria for DTC P0420. See «DTC P0420: CATALYST SYSTEM LOW EFFICIENCY»(ref-121492-S34091574562001082900000) under DIAGNOSTIC TESTS. Operate vehicle within code enable criteria until scan tool indicates diagnostic test has run. Using scan tool, observe I/M system status display. If CATALYST system status updates to YES, go to next step. If CATALYST system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S34798335492001100800000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

The PCM runs a maximum of 12 tests per trip until the catalyst system status updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M system status updates to YES. The I/M system status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M system status updates to YES. If a test for a specific system has failed, the I/M system status updates to YES, indicating a determination was made, even if all of the required tests have not run. When a failure occurs, the emission related DTC portion of the I/M system status display indicates the malfunction indicator light is requested. The I/M system status also registers the number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S15282414992001100800000) . Turn off all accessories, including A/C and blower fan. Start engine and allow it to idle. Accelerate at part throttle to 45 MPH and maintain speed for one minute. Perform 4 decelerations of 25 seconds each from 45 MPH while maintaining the following criteria: Throttle is closed. No brake application. No manual downshift. Vehicle speed remains greater than 25 MPH. After each deceleration period, vehicle speed is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. Using scan tool, observe I/M system status display. If EGR system status updates to YES, go to step 5 . If EGR system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0401, P0404, P0405 and P1404 have run. For those DTCs that have not run, operate vehicle under conditions to meet code enable criteria until DTC(s) runs. See CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Using scan tool, observe I/M system status display. If EGR system status updated to YES, go to next step. If EGR system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S35278676732001100800000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

Powertrain control module only runs the EGR active tests during a gradual deceleration with a closed throttle and with vehicle speed greater than 23 MPH. Several deceleration cycles may be necessary in order to accumulate a sufficient number of EGR flow samples. This procedure is for a clear, flat road. If procedure is performed on a road with a slight downhill grade, the test may acquire the necessary sample counters in one or 2 decel trips. If the test is interrupted during the procedure, it may take more than 10 deceleration cycles in order to complete the test. If the status does not update, the test outlined in this procedure can be repeated until the I/M system status updates to YES.

I/M system status does not indicate whether test has passed or failed, only that test has run. When all diagnostics for a specific system have run and passed, I/M system status will update to YES. If a test for a specific system has failed, I/M system status will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, the DTC emission related DTC portion of the I/M system status display will indicate malfunction indicator light is requested. I/M system status also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Using a scan tool, select SPECIAL FUNCTIONS. Determine if vehicle is equipped with a SERVICE BAY TEST for EVAP system. If vehicle equipped with EVAP SERVICE BAY TEST, go to next step. If vehicle is not equipped with EVAP SERVICE BAY TEST, go to step 5 .
3. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S11783320472001100800000) . Turn off all accessories, including A/C and blower fan. Follow scan tool instructions and perform EVAP SERVICE BAY TEST. If EVAP system passed SERVICE BAY TEST, go to step 8 . If EVAP system did not pass SERVICE BAY TEST, go to next step.
4. Observe scan tool SERVICE BAY TEST for an indication of why test did not pass. Example, a failed DTC or test aborted. Refer to appropriate service information for diagnosis and repair of condition as necessary. After repairs, perform «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-121492-S20653314242001090400000) .
5. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S11783320472001100800000) . Turn off all accessories, including A/C and blower fan. Start engine and allow it to idle. Operate vehicle under the following conditions: Acceleration at part throttle to 45 MPH. Maintain this speed until engine reaches normal operating temperature. This may take 8-10 minutes depending on start-up coolant temperature. Continue the operating conditions for an additional 3 minutes after engine reaches normal operating temperature, or until I/M system status indicator updates to YES. If EVAP system status updates to YES, go to step 8 . If EVAP system status does not update to YES, go to next step.
6. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
7. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0440, P0442, P0446 and P1441 have run. For those DTCs that have not run, operate vehicle under conditions to meet code enable criteria until DTC(s) runs. See CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Using scan tool, observe I/M system status display. If EVAP system status updated to YES, go to next step. If EVAP system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S32051488152001100800000) .
8. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

Extreme high or low ambient temperatures may prevent EVAP system tests from initiating. Performing a visual inspection prior to running test may prevent having to repeat test. A loose fuel cap may cause test to abort or fail and prevent I/M system from updating. A failed or aborted test will require vehicle to cool down in order to meet enable criteria to run another test.

I/M system status does not indicate whether test has passed or failed, only that test has run. When all diagnostics for a specific system have run and passed, I/M system status will update to YES. If a test for a specific system has failed, I/M system status will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, the DTC emission related DTC portion of the I/M system status display will indicate malfunction indicator light is requested. I/M system status also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S34182734062001100800000) . Turn off all accessories, including A/C and blower fan. Start engine and allow it to idle. Accelerate at part throttle to 45-55 MPH and maintain speed for 6 minutes or until I/M system status updates to YES. Using scan tool, observe I/M system status. If HO2S/O2S system status updated to YES, go to step 5 . If HO2S/O2S system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0133, P0140, P0153, P1133, P1134, P1153 and P1154 have run. For those DTCs that have not run, operate vehicle under conditions to meet code enable criteria until DTC(s) runs. See CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Using scan tool, observe I/M system status display. If HO2S/O2S system status updated to YES, go to next step. If HO2S/O2S system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S40144278662001100800000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

If status does not update, test outlined in this procedure can be repeated until I/M system status updates to YES.

I/M system status does not indicate whether test has passed or failed, only that test was run. When all diagnostics for a specific system have run and passed, I/M system status will update to YES. If a test for a specific system has failed, I/M system status will update to YES, indicating a determination was made, even if all required tests have not run. When a failure occurs, DTC portion of the I/M system status display will indicate malfunction indicator light is requested. I/M system status also registers number of DTCs.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If there is an impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not run after numerous attempts and no DTC is set, review appropriate scan tool data list and service information for an indication of why test does not complete. Some tests may abort due to changes in conditions while test is running. For example, changes in engine load, such as a cooling fan or an A/C compressor clutch turning on, may cause test to abort.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

1. If I/M system check has been performed, go to next step. If I/M system check has not been performed, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-121492-S27854513692001091000000) .
2. Preprogram scan tool with vehicle information before ignition is turned on. Ensure vehicle is operating with conditions for running this procedure. See «ENABLE CRITERIA»(ref-121492-S22062960892001100800000) . Turn off all accessories, including A/C and blower fan. Set vehicle parking brake. Verify transmission is in Park. Start engine and allow it to idle for 2 minutes or until I/M system status indicator updates to YES. If HO2S heater system status updates to YES, go to step 5 . If HO2S heater system status did not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe NOT RAN SINCE CODE CLEARED display to determine if DTCs P0135, P0141 and P0155 have run. For those DTCs that have not run, operate vehicle under conditions to meet code enable criteria until DTC(s) runs. See CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Using scan tool, observe I/M system status display. If HO2S heater system status updated to YES, go to next step. If HO2S heater system status did not update to YES, see «DIAGNOSTIC AIDS»(ref-121492-S33093161452001100800000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If scan tool does not indicate any emission related DTCs, system is okay.

HO2S heater tests will normally run within 2 minutes allotted in procedure. If there is impending failure, system may require more time to run diagnostic than was allotted in set procedure. If test does not update within allotted period of time, continue operation within enable conditions until test updates to YES. If test does not update to YES, it may have failed or aborted due to loss of enabling conditions. Extremely high ambient temperatures may prevent HO2S heater test from initiating.

First failure of a type "B" DTC does not constitute a final determination of pass or fail, and will not update I/M system status to YES. A second trip is required, and all conditions to run must be met in order for test to run again. These conditions may include a partial or complete engine cool down. I/M system status will update only when DTC fails second time, or if all tests pass.

If a diagnostic test is difficult to run, observe I/M system status display while maintaining necessary enable conditions until system status updates to YES.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Note. Use of Tech 2 scan tool is required to retrieve DTCs. Refer to user reference manual supplied with scan tool.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

1. Check for an open or short to ground in Orange wire between ground and terminal No. 16 at Data Link Connector (DLC). (Scheme 1) If an open or short to ground does not exist, go to next step. If an open or short to ground exists, repair wiring harness as necessary. After repair is complete, perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for an open in Black wire between ground and terminal No. 4 at DLC. If an open does not exist, go to next step. If an open exists, repair wiring harness as necessary. After repair is complete, perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
3. Inspect terminals No. 4 (Black wire) and No. 16 (Orange wire) at DLC for poor connections. If connections are okay, go to next step. If poor connections are found, repair as necessary. After repair is complete, perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
4. Scan tool may be faulty. See scan tool manufacturer's user guide. Obtain a known-good scan tool. Perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.

Fuse No. 4 (ALDL fuse) in rear fuse block supplies power to DLC terminal No. 16 (Orange wire). Rear fuse block is located underneath driver's side rear seat. If DLC voltage and ground circuits are functioning properly, malfunction must be due to scan tool or scan tool cables.

DIAGNOSTIC TESTS

Note. Before clearing DTCs, perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM CHECKS. Record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared.

Note. If Powertrain Control Module (PCM) is replaced, NEW PCM must be programmed. See PROGRAMMING .

Note. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Bank 2 sensor 1 is located in left (front) exhaust manifold.

Scheme 2

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Recheck for DTCs. If DTCs P0030, P0036, P1031 and P1032 are all set, go to step 11. If DTCs P0030, P0036, P1031 and P1032 are not all set, go to next step.
3. If DTCs P0030, P1031 and P1032 are all set, go to step 7. If DTCs P0030, P1031 and P1032 are not all set, go to next step.
4. If DTC P0030 is set, go to next step. If DTC P0030 is not set, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "D" (Dark Green wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is more than 10 volts, go to step 15. If voltage is 10 volts or less, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for short to ground in Dark Green wire between terminal "D" at HO2S bank 1 sensor 1 harness connector and terminal No. 31 at PCM C1 harness connector. see scheme 2 Also check if Dark Green wire at terminal "D" is shorted to Black/White wire at terminal "C" at HO2S bank 1 sensor 1 harness connector. If Dark Green wire is shorted to ground or shorted to Black/White wire, repair wiring as necessary. After repairs, go to step 18. If wiring is okay, go to step 17.
7. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "C" (Black/White wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is more than 10 volts, go to step 15. If voltage is 10 volts or less, go to next step.
8. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "C" (Black/White wire) at HO2S bank 1 sensor 1 harness connector. If voltage is 1.2-1.7 volts, go to step 14. If voltage is not 1.2-1.7 volts, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal "C" (Black/White wire) at HO2S bank 1 sensor 1 harness connector. If test light illuminates, repair short to ground in Black/White wire between PCM and HO2S bank 1 sensor 1. After repairs, go to step 18. If test light does not illuminate, go to next step.
10. Using a test light connected to positive battery voltage, probe terminal "C" (Black/White wire) at HO2S bank 2 sensor 1 harness connector. If test light illuminates, repair short to ground in Black/White wire between PCM and HO2S bank 2 sensor 1. After repairs, go to step 18. If test light does not illuminate, go to step 17.
11. Turn ignition off. Remove fuse No. 20 (OXY SEN fuse) from underhood fuse block. Using a test light connected to positive battery voltage, probe fuse No. 20 output terminal (closest terminal to windshield). Observe test light and disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. If test light turns off, go to step 14. If test light does not turn off, go to next step.
12. Observe test light and disconnect HO2S bank 1 sensor 2 connector. HO2S bank 1 sensor 2 is located behind catalytic converter. If test light turns off, go to step 16. If test light does not turn off, go to next step.
13. Repair short to ground in Pink/Black wire between HO2S bank 2 sensor 1 and underhood fuse block or Pink wire between HO2S bank 1 sensor 2 and underhood fuse block. After repairs, go to step 18.
14. Replace HO2S bank 2 sensor 1. After repairs, go to step 18.
15. Replace HO2S bank 1 sensor 1. After repairs, go to step 18.
16. Replace HO2S bank 1 sensor 2. After repairs, go to step 18.
17. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
18. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
19. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. HO2S bank 1 sensor 2 is located behind catalytic converter.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Recheck for DTCs. If DTC P0030, P1031 and/or P1032 is set, go to «DTC P0030: HO2S HEATER CONTROL CIRCUIT VOLTAGE IS GREATER THAN PCM INTERNAL DRIVER CAPACITY»(ref-121492-S24747406752001090400000). If only DTC P0036 is set, go to next step.
3. Start engine and allow it to reach normal operating temperature. Using scan tool, clear DTCs. Recheck for DTCs. If DTC P0036 resets, go to next step. If DTC P0036 does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect HO2S bank 1 sensor 2. HO2S bank 1 sensor 2 is located behind catalytic converter. Turn ignition on. Using a test light connected to ground, probe terminal "D" (Pink wire) at HO2S bank 1 sensor 2 harness connector. (Scheme 2) If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
5. Leave HO2S bank 1 sensor 2 disconnected. Start engine. Using a test light connected to positive battery voltage, probe terminal "C" (Black/White wire) at HO2S bank 1 sensor 2 harness connector. If test light illuminates, leave test light connected and go to next step. If test light does not illuminate, go to step 7.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. If test light illuminates, go to step 13. If test light does not illuminate, go to step 15.
7. Turn ignition off. Ensure test light is still connected between positive battery voltage and terminal "C" (Black/White wire) at HO2S bank 1 sensor 2 harness connector. Turn ignition on. Using scan tool, command HO2S HEATER DRIVER 4 on and off. If test light turns on and off, go to step 12. If test light does not turn on and off, go to next step.
8. Turn ignition off. Check continuity of Black/White wire between terminal "C" at HO2S bank 1 sensor 2 harness connector and terminal No. 48 at PCM C2 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Black/White wire. After repairs, go to step 16. If continuity exists, go to next step.
9. Measure voltage between ground and terminal "C" (Black/White wire) at HO2S bank 1 sensor 2 harness connector. If any voltage is indicated, repair short to voltage in Black/White wire between HO2S and PCM. After repairs, go to step 16. If no voltage is indicated, go to next step.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to 16. If connectors are okay, go to step 15.
11. Repair open in Pink wire between HO2S bank 1 sensor 2 and underhood fuse block. After repairs, go to step 16.
12. Check for poor connections at HO2S bank 1 sensor 2 connector. Repair as necessary. After repairs, go to step 16. If connector is okay, go to next step.
13. Repair short to ground in Black/White wire between HO2S bank 1 sensor 2 and PCM. After repairs, go to step 16.
14. Replace HO2S bank 1 sensor 2. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check for sticking throttle plate. Check for carbon build-up on throttle plate and throttle bore. Unmetered air entering the engine may cause this DTC to set. Ensure oil dipstick is fully seated and oil filler cap is secure. Check for misrouted or damaged MAF/IAT sensor wiring harness. Ensure harness is not close to high-voltage components. Check for non-factory or aftermarket add-on devices.

Scheme 3

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Using scan tool, check MAF sensor frequency parameter. If frequency reading is 1135 Hz or more, go to next step. If frequency reading is less than 1135 Hz, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S33171956002001090600000).
4. Turn ignition off. Check fuse No. 11 (IGN 1 fuse) in underhood fuse block. If fuse is okay, go to next step. If fuse is blown, go to step 14.
5. Disconnect MAF/IAT sensor connector. Turn ignition on. Measure voltage between ground and terminal "E" (Yellow wire) at MAF/IAT sensor harness connector. (Scheme 3) If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 8.
6. Turn ignition off. Connect a 3-amp fused jumper wire between ground and terminal "E" (Yellow wire) at MAF/IAT sensor harness connector. Start engine. Using scan tool, observe 5-volt reference 1 and 5-volt reference 2 parameters. If scan tool indicates OK, go to next step. If scan tool does not indicate OK, go to step 16.
7. Turn ignition off. Connect a test light between terminal "D" (Pink/White wire) and terminal "C" (Black/White wire) at MAF/IAT sensor harness connector. Turn ignition on. If test light illuminates, go to step 18. If test light does not illuminate, go to step 11.
8. If voltage measured in step 5 is less than 4.5 volts, go to step 10. If voltage measured in step 5 is not less than 4.5 volts, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal "E" (Yellow wire) at MAF/IAT sensor harness connector. If no voltage is indicated, go to step 12. If any voltage is indicated, go to step 15.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in Yellow wire between terminal "E" at MAF/IAT sensor harness connector and terminal No. 42 at PCM C1 harness connector. see scheme 2and (Scheme 3). Also check if Yellow wire at terminal "E" is shorted to Black/White wire at terminal "C" at MAF/IAT sensor harness connector. If Yellow wire is open, shorted to ground or shorted to Black/White wire, repair wiring as necessary. After repairs, go to step 22. If wiring is okay, go to step 12.
11. Using a test light connected to ground, probe terminal "D" (Pink/White wire) at MAF/IAT sensor harness connector. If test light illuminates, go to step 13. If test light does not illuminate, go to step 14.
12. Check for continuity between terminal No. 42 (Yellow wire) at PCM C1 harness connector and all other terminals at both PCM C1 and C2 harness connectors. see scheme 2 If continuity exists between any terminals, go to step 17. If continuity does not exist between any terminals, go to step 19.
13. Repair open or high resistance in Black/White wire between ground and terminal "C" at MAF/IAT sensor harness connector. See WIRING DIAGRAMS article. After repairs, go to step 22.
14. Repair short to ground or open in Pink/White wire between underhood fuse block and terminal "D" at MAF/IAT sensor harness connector. Also check fuse No. 11 (IGN 1 fuse) in underhood fuse block. Replace fuse as necessary. After repairs, go to step 22.
15. Repair short to voltage in Yellow wire between PCM and MAF/IAT sensor. After repairs, go to step 22.
16. Repair short between Yellow wire at MAF/IAT sensor harness connector and circuit of 5-volt reference parameter that did not display OK. The 5-volt reference 1 circuit supplies reference voltage to TP sensor, MAP sensor and EGR position sensor. The 5-volt reference 2 circuit supplies reference voltage to A/C pressure sensor and fuel tank pressure sensor. After repairs, go to step 22.
17. Repair circuits that are shorted together. After repairs, go to step 22.
18. Check for poor connections at MAF/IAT sensor connector. Repair connector as necessary. After repairs, go to step 22. If connector is okay, go to step 20.
19. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 22. If connectors are okay, go to step 21.
20. Replace MAF/IAT sensor. After repairs, go to step 22.
21. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
22. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
23. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Low minimum air rate may cause this DTC to set. Check for plugged or misaligned intake air duct. Check for dirty air filter. Check for objects blocking MAF/IAT sensor air inlet screen. Any unmetered air entering engine may also cause this DTC to set. Ensure oil dipstick is fully seated and oil filler cap is secure. Check for misrouted or damaged MAF/IAT sensor wiring harness. Ensure harness is not close to high-voltage components.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S21180019752001082900000) .
3. Turn ignition off. Disconnect MAF/IAT sensor connector. Start engine. Using scan tool, check MAF sensor frequency parameter. If frequency reading is zero Hz, go to step 5 . If frequency reading is not zero Hz, go to next step.
4. Check MAF/IAT sensor wiring harness for incorrect routing near ignition control modules, solenoids, relays or motors. If any problems are found, reroute wiring harness as necessary. After repairs, go to step 9 . If no problems are found, go to step 6 .
5. Check for poor connections at MAF/IAT sensor connector. Repair connector as necessary. After repairs, go to step 9 . If connector is okay, go to step 7 .
6. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 9 . If connectors are okay, go to step 8 .
7. Replace MAF/IAT sensor. After repairs, go to step 9 .
8. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to next step.
9. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
10. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Water entering air intake system that reaches MAF/IAT sensor could cause this DTC to set. Water rapidly cools the hot sensing elements in the MAF/IAT sensor causing a false indication of excessive airflow. Check for evidence of water intrusion in the secondary air injection system and the air induction system. Check for faulty connections at MAF/IAT sensor connector.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe TP sensor angle parameter from closed throttle to wide open throttle. If TP sensor value changed from zero to 98 percent smoothly, go to next step. If TP sensor value did not change from zero to 98 percent or did not change smoothly, go to «DTC P0121: THROTTLE POSITION SENSOR CIRCUIT INSUFFICIENT ACTIVITY»(ref-121492-S07550945922001082900000).
3. Using scan tool, observe MAP sensor pressure. Compare this value to MAP sensor value observed from a known-good vehicle. If difference between readings is less than.43 psi, go to next step. If difference between readings is.43 psi or more, go to step 8.
4. Using scan tool, observe MAP sensor pressure. Start engine. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 8.
5. Turn ignition off. Remove MAP sensor vacuum source. see scheme 5 Leave MAP sensor electrical connector connected. Connect a hand operated vacuum pump to MAP sensor vacuum port. Turn ignition on. Using scan tool, observe MAP sensor parameter while slowly applying vacuum one in. Hg at a time. Apply up to 20 in. Hg. Each one in. Hg of vacuum applied should result in a.4-.6 psi (3-4 kPa) drop in MAP sensor value indicated on scan tool. MAP sensor value should change smoothly with each one in. Hg increase. If MAP sensor value changed smoothly through entire range of test, go to next step. If MAP sensor value did not change smoothly through entire range of test, go to step 16.
6. Observe scan tool and apply 20 in. Hg vacuum to MAP sensor. If scan tool indicates MAP sensor reading is 4.9 psi (34 kPa) or less, go to next step. If scan tool indicates MAP sensor reading is more than 4.9 psi (34 kPa), go to step 8.
7. Disconnect vacuum source from MAP sensor. If MAP sensor reading returns to original value in step 3, see «DIAGNOSTIC AIDS»(ref-121492-S23937934582001082900000). If MAP sensor reading does not return to original value, go to step 16.
8. Turn ignition off. Disconnect MAP sensor connector. Using scan tool, observe MAP sensor voltage. Turn ignition on. If voltage is more than.5 volt, go to step 15. If voltage is.5 volt or less, go to next step.
9. Connect a 3-amp fused jumper wire between Gray and Light Green wires at MAP sensor harness connector. Using scan tool, observe MAP sensor voltage. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 14.
10. Remove jumper wire. Measure voltage between ground and Gray wire at MAP sensor harness connector. If voltage is more than 5.2 volts, go to step 12. If voltage is 5.2 volts or less, go to next step.
11. Using a test light connected to positive battery voltage, probe Orange/Black wire at MAP sensor harness connector. If test light illuminates, go to step 16. If test light does not illuminate, go to step 13.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Gray wire at MAP sensor harness connector. If any voltage is indicated, repair short to voltage in Gray wire between MAP sensor and PCM. After repairs, go to step 20. If no voltage is indicated, go to step 17.
13. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Orange/Black wire between MAP sensor harness connector and terminal No. 6 at PCM C2 harness connector. see scheme 2 If continuity does not exist, repair open in Orange/Black wire. After repairs, go to step 20. If continuity exists, go to step 17.
14. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Light Green wire between MAP sensor harness connector and terminal No. 23 at PCM C1 harness connector. see scheme 2 If continuity does not exist, repair open in Light Green wire. After repairs, go to step 20. If continuity exists, go to step 17.
15. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Light Green wire at MAP sensor harness connector. If any voltage is indicated, repair short to voltage in Light Green wire between MAP sensor and PCM. After repairs, go to step 20. If any voltage is indicated, go to step 17.
16. Check for poor connections at MAP sensor connector. Repair connector as necessary. After repairs, go to step 20. If connector is okay, go to step 18.
17. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 20. If connectors are okay, go to step 19.
18. Replace MAP sensor. After repairs, go to step 20.
19. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
20. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
21. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check for restricted MAP sensor vacuum source. Check for missing or damaged MAP sensor seal. Check for disconnected, damaged, or incorrectly routed vacuum hoses. Check for vacuum leaks at intake manifold and throttle body. If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Using scan tool, check for any other DTCs that are set. If DTC P1635 is not set, go to next step. If DTC P1635 is set, go to «DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT»(ref-121492-S40727140912001082900000).
3. Using scan tool, observe MAP sensor voltage. If voltage is less than.5 volt, go to step 5. If voltage is.5 volt or more, go to next step.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S40672261272001090700000).
5. Turn ignition off. Disconnect MAP sensor connector. see scheme 5 Turn ignition on. Measure voltage between ground and Gray wire at MAP sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 7.
6. Connect a 3-amp fused jumper wire between Gray and Light Green wires at MAP sensor harness connector. Using scan tool, observe MAP sensor voltage. If voltage is about 5 volts, go to step 9. If voltage is not about 5 volts, go to step 8.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in Gray wire between MAP sensor harness connector and terminal No. 49 at PCM C2 harness connector. see scheme 2 If an open or short to ground exists, repair wiring as necessary. After repairs, go to step 13. If an open or short to ground does not exist, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in Light Green wire between MAP sensor harness connector and terminal No. 23 at PCM C1 harness connector. see scheme 2 If an open or short to ground exists, repair wiring as necessary. After repairs, go to step 13. If an open or short to ground does not exist, go to step 10.
9. Check for poor connections at MAP sensor connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to step 11.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to step 12.
11. Replace MAP sensor. After repairs, go to step 13.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check MAP sensor vacuum source for leaks, restrictions or poor connections. If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Using scan tool, check for any other DTCs that are set. If DTC P1635 is not set, go to next step. If DTC P1635 is set, go to «DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT»(ref-121492-S40727140912001082900000). NOTE: If engine idle is rough, unstable or incorrect, correct idle condition before continuing with this test. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Using scan tool, observe MAP sensor voltage. If voltage is 4.5 volts, go to step 5. If voltage is not 4.5 volts, go to next step.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S11696619432001090700000).
5. Turn ignition off. Disconnect MAP sensor connector. see scheme 5 Turn ignition on. Using scan tool, observe MAP sensor voltage. If voltage is less than.5 volt, go to next step. If voltage is.5 volt or more, go to step 8.
6. Measure voltage between Gray and Orange/Black wires at MAP sensor harness connector. If voltage is 4.7-5.2 volts, go to step 11. If voltage is not 4.7-5.2 volts, go to next step.
7. If voltage was more than 5.2 volts in previous step, go to step 10. If voltage was less than 4.7 volts in previous step, go to step 9.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Light Green wire at MAP sensor harness connector. If any voltage is indicated, repair wiring as necessary. After repairs, go to step 15. If no voltage is indicated, go to step 12.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Orange/Black wire between MAP sensor harness connector and terminal No. 6 at PCM C2 harness connector. see scheme 2 If continuity does not exist, repair open in Orange/Black wire. After repairs, go to step 15. If continuity exists, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Gray wire at MAP sensor harness connector. If any voltage is indicated, repair wiring as necessary. After repairs, go to step 15. If no voltage is indicated, go to step 12.
11. Check for poor connections at MAP sensor connector. Repair connector as necessary. After repairs, go to step 15. If connector is okay, go to step 13.
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 15. If connectors are okay, go to step 14.
13. Replace MAP sensor. After repairs, go to step 15.
14. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
15. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
16. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check MAP sensor vacuum source for leaks, restrictions or poor connections. If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe IAT sensor temperature. If temperature reading is more than 257°F (125°C), go to step 4. If temperature reading is 257°F (125°C) or less, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect MAF/IAT sensor connector. IAT sensor is integral to MAF sensor. Turn ignition on. Using scan tool, observe IAT sensor temperature. If temperature reading is about -40°F (-40°C), go to step 6. If temperature reading is not about -40°F (-40°C), go to next step.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for short to ground in Tan wire between terminal "B" at MAF/IAT sensor harness connector and terminal No. 10 at PCM C1 harness connector. see scheme 2and (Scheme 3). Also check if Tan wire at terminal "B" is shorted to Black wire at terminal "A" or Black/White wire at terminal "C" at MAF/IAT sensor harness connector. If Tan wire is shorted to ground, or shorted to Black wire or Black/White wire, repair wiring as necessary. After repairs, go to step 8. If wiring is okay, go to step 7.
6. Replace MAF/IAT sensor. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe IAT sensor temperature parameter. If temperature reading is less than -11°F (-24°C), go to step 4. If temperature reading is -11°F (-24°C) or more go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect MAF/IAT sensor connector. IAT sensor is integral to MAF sensor. Turn ignition on. Measure voltage between ground and terminal "B" (Tan wire) at MAF/IAT sensor harness connector. (Scheme 3) If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 10.
5. Turn ignition off. Connect a jumper wire between terminal "A" (Black wire) and terminal "B" (Tan wire) at MAF/IAT sensor harness connector. Turn ignition on. Using scan tool, observe 5-volt reference 1 and 5-volt reference 2 parameters. If scan tool indicates OK, leave jumper wire connected and go to step 7. If scan tool does not indicate OK, go to next step.
6. Repair short between Tan wire at MAF/IAT sensor harness connector and circuit of 5-volt reference parameter that did not display OK. The 5-volt reference 1 circuit supplies reference voltage to TP sensor, MAP sensor and EGR position sensor. The 5-volt reference 2 circuit supplies reference voltage to A/C pressure sensor and fuel tank pressure sensor. After repairs, go to step 15.
7. Using scan tool, observe IAT sensor temperature parameter. If temperature reading is about 302°F (150°C), go to next step. If temperature reading is not about 302°F (150°C), go to step 9.
8. Check for poor connections at MAF/IAT sensor connector. Repair connector as necessary. After repairs, go to step 15. If connector is okay, go to step 13.
9. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM and MAF/IAT sensor connectors. Repair connectors as necessary. Check continuity of Black wire between terminal "A" at MAF/IAT sensor harness connector and terminal No. 4 at PCM C2 harness connector. see scheme 2and (Scheme 3). If continuity exists, go to step 14. If continuity does not exist, repair open in Black wire. After repairs, go to step 15.
10. If voltage measured in step 4 is 5 volts or less, go to step 12. If voltage measured in step 4 is more than 5 volts, go to next step.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal "B" (Tan wire) at MAF/IAT sensor harness connector. If any voltage is indicated, repair short to voltage in Tan wire between MAF/IAT sensor and PCM. After repairs, go to step 15. If no voltage is indicated, go to step 14.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM and MAF/IAT sensor connectors. Repair connectors as necessary. Check continuity of Tan wire between terminal "B" at MAF/IAT sensor harness connector and terminal No. 10 at PCM C1 harness connector. see scheme 2and (Scheme 3). If continuity exists, go to step 14. If continuity does not exist, repair open in Tan wire. After repairs, go to step 15.
13. Replace MAF/IAT sensor. After repairs, go to step 15.
14. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
15. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
16. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe ECT sensor temperature. If temperature reading is more than 257°F (125°C), go to step 4. If temperature reading is 257°F (125°C) or less, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S30975809962001091000000).
4. Turn ignition off. Disconnect ECT sensor harness connector. see scheme 5 Turn ignition on. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature reading is about -40°F (-40°C), go to step 6. If ECT sensor temperature reading is not about -40°F (-40°C), go to next step.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 31 (Yellow wire) at PCM C2 harness connector. see scheme 2 If test light illuminates, repair short to ground in Yellow wire between ECT sensor and PCM. After repairs, go to step 8. If test light does not illuminate, go to 7.
6. Replace ECT sensor. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe ECT sensor temperature. If temperature reading is less than -11°F (-24°C), go to step 4. If temperature reading is -11°F (-24°C) or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S06289732712001091000000).
4. Turn ignition off. Disconnect ECT sensor connector. see scheme 5 Turn ignition on. Measure voltage between ground and Yellow wire at ECT sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 10.
5. Connect a 3-amp jumper wire between Black and Yellow wires at ECT sensor harness connector. Using scan tool, observe 5-volt reference 1 and 5-volt reference 2 parameters. If scan tool indicates OK, leave jumper wire connected and go to step 7. If scan tool does not indicate OK, go to next step.
6. Repair short between Yellow wire at ECT sensor harness connector and circuit of 5-volt reference parameter that did not display OK. The 5-volt reference 1 circuit supplies reference voltage to TP sensor, MAP sensor and EGR position sensor. The 5-volt reference 2 circuit supplies reference voltage to A/C pressure sensor and fuel tank pressure sensor. After repairs, go to step 15.
7. Using scan tool, observe ECT sensor temperature. If temperature reading is about 302°F (150°C), go to next step. If temperature reading is not about 302°F (150°C), go to step 9.
8. Check for poor connections at ECT sensor connector. Repair connector as necessary. After repairs, go to step 15. If connector is okay, go to step 13.
9. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black wire between ECT sensor harness connector and terminal No. 68 at PCM C2 harness connector. see scheme 2 If continuity exists, go to step 14. If continuity does not exist, repair open in Black wire. After repairs, go to step 15.
10. If voltage measured in step 4 is more than 5 volts, go to next step. If voltage measured in step 4 is not more than 5 volts, go to step 12.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 31 (Yellow wire) at PCM C2 harness connector. see scheme 2 If no voltage is indicated, go to step 14. If any voltage is indicated, repair short to voltage in Yellow wire between PCM and ECT sensor. After repairs, go to step 15.
12. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Yellow wire between ECT sensor harness connector and terminal No. 31 at PCM C2 harness connector. see scheme 2 If continuity exists, go to step 14. If continuity does not exist, repair open in Yellow wire. After repairs, go to step 15.
13. Replace ECT sensor. After repairs, go to step 15.
14. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
15. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
16. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If an intermittent condition exists, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe TP sensor angle parameter while slowly opening throttle to WOT. If TP sensor angle increased steadily from zero percent to 98 percent, go to next step. If TP sensor angle did not increase steadily from zero percent to 98 percent, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S13721497982001091000000).
4. Turn ignition off. Disconnect TP sensor connector. see scheme 5 Turn ignition on. Using scan tool, observe TP sensor voltage. If voltage is zero volts, go to next step. If voltage is not zero volts, to step 6.
5. Turn ignition off. Connect a 3-amp fused jumper wire between Gray and Dark Blue wires at TP sensor harness connector. Using scan tool, observe TP sensor voltage. If voltage is 5 volts, go to step 9. If voltage is not 5 volts, go to step 7.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 62 (Dark Blue wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Dark Blue wire. After repairs, go to 14. If no voltage is indicated, go to step 12.
7. Turn ignition off. Check continuity of Gray wire between TP sensor harness connector and terminal No. 51 at PCM C2 harness connector. If continuity exists, go to next step. If continuity does not exist, repair open in Gray wire. After repairs, go to step 14.
8. Check continuity of Dark Blue wire between TP sensor harness connector and terminal No. 62 at PCM C1 harness connector. If continuity exists, go to step 11. If continuity does not exist, repair open in Dark Blue wire. After repairs, go to step 14.
9. Check continuity of Black/White wire between TP sensor harness connector and terminal No. 69 at PCM C2 harness connector. If continuity exists, go to next step. If continuity does not exist, repair open in Black/White wire. After repairs, go to step 14.
10. Check for poor connections at TP sensor connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 12.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
12. Replace TP sensor. After repairs, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

A skewed MAP sensor signal may cause PCM to incorrectly determine that the TP sensor is out of range. Check for an unusually low or high MAP sensor reading. If DTC is determined to be intermittent or TP sensor system is still suspect, go to DTC P1121: THROTTLE POSITION SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE and/or INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe TP sensor voltage parameter. If voltage is less than.16 volt, go to step 4. If voltage is.16 or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, go to «DTC P1122: THROTTLE POSITION SENSOR CIRCUIT INTERMITTENT LOW VOLTAGE»(ref-121492-S35328235532001082900000).
4. Turn ignition off. Disconnect TP sensor connector. see scheme 5 Connect a 3-amp fused jumper wire between Gray and Dark Blue wires at TP sensor harness connector. Turn ignition on. Using scan tool, observe TP sensor voltage. If voltage is 5 volts, go to step 11. If voltage is not 5 volts, go to next step.
5. Remove jumper wire. Measure voltage between Gray and Black/White wires at TP sensor harness connector. If voltage is about 5 volts, go to step 9. If voltage is not about 5 volts, go to next step.
6. Turn ignition off. Check continuity of Gray wire between TP sensor harness connector and terminal No. 51 at PCM C2 harness connector. If continuity exists, go to next step. If continuity does not exist, repair open in Gray wire. After repairs, go to step 14.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe Gray wire at TP sensor harness connector. If test light does not illuminate, go to next step. If test light illuminates, repair short to ground in Gray wire between TP sensor and PCM. After repairs, go to step 14.
8. Reconnect PCM connectors. Connect DVOM between Gray and Black/White wires at TP sensor harness connector. Turn ignition on. Observe voltage reading while disconnecting all sensors, one at a time, that use a 5-volt reference signal. If voltage reading changes, replace sensor that caused voltage to change. After repairs, go to step 14. If voltage does not change, reconnect connectors and go to step 10.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Dark Blue wire between TP sensor harness connector and terminal No. 62 at PCM C1 harness connector. If continuity exists, go to next step. If continuity does not exist, repair open in Dark Blue wire. After repairs, go to step 14.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
11. Check for poor connections at TP sensor connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to next step.
12. Replace TP sensor. After repairs, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, observe TP sensor voltage parameter with throttle closed. If voltage is more than 4.8 volts, go to step 4. If voltage is 4.8 volts or less, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, go to «DTC P1121: THROTTLE POSITION SENSOR CIRCUIT INTERMITTENT HIGH VOLTAGE»(ref-121492-S38286609382001082900000).
4. Turn ignition off. Disconnect TP sensor. see scheme 5 Turn ignition on. Using scan tool, observe TP sensor voltage parameter. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 8.
5. Measure voltage between ground and Gray wire at TP sensor harness connector. If voltage is 5 volts, go to next step. If voltage is not 5 volts, go to step 9.
6. Using a test light connected to positive battery voltage, probe Black/White wire at TP sensor harness connector. If test light illuminates, go to step 10. If test light does not illuminate, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black/White wire between TP sensor harness connector and terminal No. 69 at PCM C2 harness connector. see scheme 2 If continuity exists, go to step 15. If continuity does not exist, repair open in Black/White wire. After repairs, go to step 18.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 62 (Dark Blue wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Dark Blue wire between PCM and TP sensor. After repairs, go to step 18. If no voltage is indicated, go to step 15.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 51 (Gray wire) at PCM C2 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Gray wire between PCM and TP sensor. After repairs, go to step 18. If no voltage is indicated, go to next step.
10. Turn ignition off. Reconnect PCM connectors. Turn ignition on. Connect a DVOM between Gray and Black/White wires at TP sensor harness connector. Note voltage reading. Using scan tool, command EGR valve to 100 percent while observing DVOM. If voltage changed, go to next step. If voltage did not change, go to step 14.
11. Disconnect EGR valve connector. see scheme 5 With DVOM still connected, command EGR valve to 100 percent. If voltage changed, go to step 13. If voltage did not change, go to next step.
12. Replace EGR valve. After repairs, go to step 18.
13. Gray wire between EGR valve and PCM is shorted to 5-volt reference circuit. Repair wiring as necessary. See WIRING DIAGRAMS article. After repairs, go to step 18.
14. Check for poor connections at TP sensor connector. Repair connector as necessary. After repairs, go to step 18. If connector is okay, go to step 16.
15. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 18. If connectors are okay, go to step 17.
16. Replace TP sensor. After repairs, go to step 18.
17. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
18. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
19. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check coolant level. If coolant level is okay, go to next step. If coolant level is low, check cooling system for leaks. Repair as necessary and top off coolant level.
3. Turn ignition off. Disconnect ECT sensor connector. see scheme 5 Connect a 3-amp fused jumper wire between Yellow and Black wires at ECT sensor harness connector. Turn ignition on. Using scan tool, observe ECT sensor temperature. If temperature reading is more than 280°F (138°C), go to step 7. If temperature reading is 280°F (138°C) or less, go to next step.
4. Turn ignition off. Disconnect jumper wire. Reconnect jumper wire between ground and Yellow wire at ECT sensor harness connector. Turn ignition on. Using scan tool, observe ECT sensor temperature. If temperature reading is more than 280°F (138°C), go to next step. If temperature reading is 280°F (138°C) or less, go to step 6.
5. Repair open or high resistance in Black wire between ECT sensor and PCM. After repairs, go to step 10.
6. Repair open or high resistance in Yellow wire between ECT sensor and PCM. After repairs, go to step 10.
7. Remove ECT sensor. Suspend ECT sensor and a thermometer in a pan of water. Place pan on a burner or hot plate. Measure resistance between ECT sensor terminals with sensor at specified temperature. See «ECT/IAT SENSOR RESISTANCE»(ref-121492-S42779891312001060500000) table. If resistance is as specified, go to next step. If resistance is not as specified, go to step 9.
8. Reinstall ECT sensor. Diagnose cooling system thermostat.
9. Replace ECT sensor. After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

DTC P0125 is designed to detect a skewed ECT sensor or a faulty thermostat. A skewed IAT sensor may also cause this DTC to set. See ECT/IAT SENSOR RESISTANCE

ECT/IAT SENSOR RESISTANCE

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If scan tool indicates voltage is varying outside 350-500 millivolts, go to next step. If scan tool does not indicate voltage is varying outside 350-500 millivolts, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Check for exhaust leaks. Ensure HO2S bank 1 sensor 1 is installed correctly. Check for damaged HO2S bank 1 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan wire) and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan wire between terminal No. 52 at PCM C1 harness connector and terminal "A" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 53 at PCM C1 harness connector and terminal "B" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 1 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is less than 300 millivolts, go to step 4. If voltage is 300 millivolts or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S13104693662001082900000).
4. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S13104693662001082900000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check if Purple/White wire at terminal "B" at HO2S bank 1 sensor 1 harness connector is shorted to ground. (Scheme 2) Also check if Purple/White wire at terminal "B" is shorted to Tan wire at terminal "A" at HO2S bank 1 sensor 1 harness connector. If Purple/White wire is shorted to ground or shorted to Tan wire, repair wiring as necessary. After repairs, go to step 7. If wiring is okay, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too low will cause a lean condition. The PCM will compensate for some decrease in fuel pressure, but if fuel pressure is too low, DTC P0131 may set. Check fuel injectors. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If fuel injectors deliver improper fuel volume, DTC P0131 may set. Check for exhaust leaks. Exhaust leaks may cause outside air to be drawn into the exhaust gas stream, and pass the HO2S. This causes HO2S signal to indicate a false lean condition. Check for Secondary Air Injection (AIR) system leaks. Check AIR system hoses, check valves, and piping for leaks. Check for poor connections or for signs of any damage. Check for disconnected or damaged vacuum hoses. Check for vacuum leaks at throttle body, EGR valve, EVAP purge solenoid, and intake manifold. Check for fuel contamination. Water, even in small amounts, can be delivered to fuel injectors. Water can cause a lean exhaust. Also, excessive alcohol in the fuel can cause a lean condition. Check with customer in order to verify conditions under which the DTC set. Check if vehicle ran out of fuel. If none of the previous conditions are set, replace HO2S. Using scan tool, review front and rear long term fuel trim values fail records data. If both banks were lean, check for a condition that would cause a lean engine operation. If only the rear bank was lean, the lean condition is isolated to that bank. Check for an intermittent short to ground on HO2S signal circuit. If condition is not set, check with customer about type of fuel used. Recommend using fuels of 10 percent or less ethanol.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is more than 600 millivolts, go to step 4. If voltage is 600 millivolts or less, go to next step.
3. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S33931717472001082900000).
4. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S33931717472001082900000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off and wait 30 seconds. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and terminal No. 53 (Purple/White wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Purple/White wire between PCM and HO2S bank 1 sensor 1. After repairs, go to step 7. If no voltage is indicated, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too high will cause a rich condition. The PCM will compensate for some increase in fuel pressure, but if fuel pressure is high enough, DTC P0132 may set. Check fuel injectors. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If fuel injectors deliver improper fuel volume, DTC P0132 may set. Check EVAP canister and hoses for fuel saturation. Check for silicone contamination. Silicone contamination of HO2S can also cause a high HO2S voltage signal. This condition is indicated by a powdery White deposit on tip of HO2S that is exposed to exhaust stream. If none of the previous conditions are present, replace HO2S. Using scan tool, review front and rear long term fuel trim values fail records data. If both banks were rich, check for a condition that would cause a rich engine operation. If only the rear bank was rich, the rich condition is isolated to that bank. Check for an intermittent short to voltage on HO2S signal circuit.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If scan tool indicates HO2S voltage varying outside 400-500 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 400-500 millivolts, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S24835260572001091200000).
4. Check for exhaust leaks. Ensure HO2S bank 1 sensor 1 is installed correctly. Check for damaged HO2S bank 1 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan wire) and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan wire between terminal No. 52 at PCM C1 harness connector and terminal "A" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 53 at PCM C1 harness connector and terminal "B" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 1 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and for poor terminal-to-wire connections. Inspect wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to HO2S bank 1 sensor 1. A change in scan tool display will indicate malfunction location. Fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since diagnostic test last failed may help to diagnose the condition. The information may help determine how often condition that set the DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If scan tool indicates HO2S voltage varying outside 400-500 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 400-500 millivolts, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S01653848902001091200000).
4. Check for exhaust leaks. Ensure HO2S bank 1 sensor 1 is installed correctly. Check for damaged HO2S bank 1 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan wire) and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan wire between terminal No. 52 at PCM C1 harness connector and terminal "A" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 53 at PCM C1 harness connector and terminal "B" at HO2S bank 1 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 1 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and for poor terminal-to-wire connections. Inspect wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to HO2S bank 1 sensor 1. A change in scan tool display will indicate malfunction location. Fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since the diagnostic test last failed may help to diagnose condition. The information may help determine how often condition that set the DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Observe DTC information for 30 seconds. If DTCs P0030, P1031 and P1032 are set, go to «DTC P0030: HO2S HEATER CONTROL CIRCUIT VOLTAGE IS GREATER THAN PCM INTERNAL DRIVER CAPACITY»(ref-121492-S24747406752001090400000). If DTCs P0030, P1031 and P1032 are not set, go to next step.
3. Start engine. Using scan tool, observe DTC information for 5 minutes. If DTCs P0135 and P0155 are set, go to step 5. If DTCs P0135 and P0155 are not set, go to next step.
4. If DTC P0135 is set, go to step 7. If DTC P0135 is not set, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Using a test light connected to ground, probe terminal "D" (Dark Green wire) at HO2S bank 1 sensor 1 harness connector. Using scan tool, command HO2S heater driver 1 on and off. If test light turns on and off, go to step 11. If test light does not turn on and off, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 31 (Dark Green wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Dark Green wire between HO2S bank 1 sensor 1 and PCM. After repairs, go to step 13. If no voltage is indicated, go to step 12.
7. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "D" (Dark Green wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If voltage is more than 10 volts, go to step 9. If voltage is 10 volts or less, go to next step.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Dark Green wire between terminal "D" at HO2S bank 1 sensor 1 harness connector and terminal No. 31 at PCM C1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Dark Green wire. After repairs, go to step 13. If continuity exists, go to step 10.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black/White wire between terminal "C" at HO2S bank 1 sensor 1 harness connector and terminal No. 68 at PCM C1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Black/White wire. After repairs, go to step 13. If continuity exists, go to next step.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to step 12.
11. Replace HO2S bank 1 sensor 1. After repairs, go to step 13.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

An intermittent open in HO2S ignition signal circuit or ground circuit may cause DTC to set. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is less than 9 millivolts, go to step 4. If voltage is 9 millivolts or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S12140341032001091700000).
4. Turn ignition off. Raise and support vehicle. Remove HO2S bank 1 sensor 2 heat shield. HO2S bank 1 sensor 2 is located behind catalytic converter. Disconnect HO2S bank 1 sensor 2 connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S12140341032001091700000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check if Dark Green/White wire at terminal "B" at HO2S bank 1 sensor 2 harness connector is shorted to ground. (Scheme 2) Also check if Dark Green/White wire at terminal "B" is shorted to Dark Blue/White wire at terminal "A" at HO2S bank 1 sensor 2 harness connector. If Dark Green/White wire is shorted to ground or shorted to Dark Blue/White wire, repair wiring as necessary. After repairs, go to step 7. If wiring is okay, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check exhaust system for leaks. Exhaust leaks may cause outside air to be drawn into the exhaust gas stream, and pass the HO2S. This causes the HO2S signal to indicate a false lean condition. For intermittent conditions, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since diagnostic test last failed may assist in diagnosing condition. Information may help determine how often condition that set DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is more than 600 millivolts, go to step 4. If voltage is 600 millivolts or less, go to next step.
3. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S18562491512001091700000).
4. Turn ignition off. Raise and support vehicle. Remove HO2S bank 1 sensor 2 heat shield. HO2S bank 1 sensor 2 is located behind catalytic converter. Disconnect HO2S bank 1 sensor 2 connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S18562491512001091700000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off and wait 30 seconds. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and terminal No. 51 (Dark Green/White wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Dark Green/White wire between PCM and HO2S bank 1 sensor 2. After repairs, go to step 7. If no voltage is indicated, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check for silicone contamination. Silicone contamination of HO2S can also cause a high HO2S voltage signal. This condition is indicated by a powdery White deposit on tip of HO2S that is exposed to exhaust stream. Reviewing failure records vehicle mileage since diagnostic test last failed may help to diagnose condition. Information may help to determine how often condition that set DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If any other DTCs are set, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If no other DTCs are set, go to next step.
3. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If scan tool indicates HO2S voltage varying outside 300-500 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 300-500 millivolts, go to step 5.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S12920028972001091700000).
5. Turn ignition off. Raise and support vehicle. Remove HO2S bank 1 sensor 2 heat shield. HO2S bank 1 sensor 2 is located behind catalytic converter. Disconnect HO2S bank 1 sensor 2 connector. Turn ignition on. Connect a jumper wire between terminal "A" (Dark Blue/White wire) and terminal "B" (Dark Green/White wire) at HO2S bank 1 sensor 2 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is less than 150 millivolts, go to step 7. If voltage is 150 millivolts or more, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Dark Blue/White wire between terminal No. 50 at PCM C1 harness connector and terminal "A" at HO2S bank 1 sensor 2 harness connector. see scheme 2and (Scheme 2). Also check continuity of Dark Green/White wire between terminal No. 51 at PCM C1 harness connector and terminal "B" at HO2S bank 1 sensor 2 harness connector. If continuity does not exist in Dark Blue/White or Dark Green/White wire, repair wiring as necessary. After repairs, go to step 11. If continuity exists in both wires, go to step 9.
7. Check for poor connections at HO2S bank 1 sensor 2 connector. Repair connector as necessary. After repairs, go to step 11. If connector is okay, go to next step.
8. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 2. After repairs, go to step 11.
9. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 11. If connectors are okay, go to next step.
10. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
11. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 3.
12. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and for poor terminal-to-wire connections. Inspect wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to HO2S bank 1 sensor 2. A change in scan tool display will indicate malfunction location. Fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since diagnostic test last failed may help to diagnose condition. The information may help determine how often condition that set DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Observe DTC information for 30 seconds. If DTC P0036 sets, go to «DTC P0036: HO2S HEATER CONTROL CIRCUIT VOLTAGE IS GREATER THAN PCM INTERNAL DRIVER CAPACITY»(ref-121492-S15446291612001090400000). If DTC P0036 is not set, go to next step.
3. Using scan tool, command HO2S heater 4 on. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If scan tool indicates HO2S voltage varying outside 400-500 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 400-500 millivolts, go to step 5.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Raise and support vehicle. Remove HO2S bank 1 sensor 2 heat shield. HO2S bank 1 sensor 2 is located behind catalytic converter. Disconnect HO2S bank 1 sensor 2 connector. Turn ignition on. Connect a jumper wire between terminal "A" (Dark Blue/White wire) and terminal "B" (Dark Green/White wire) at HO2S bank 1 sensor 2 harness connector. (Scheme 2) Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is less than 150 millivolts, go to step 9. If voltage is 150 millivolts or more, go to next step.
6. Turn ignition off. Disconnect jumper wire. Reconnect jumper wire between ground and terminal "B" (Dark Green/White wire) at HO2S bank 1 sensor 2 harness connector. Using scan tool, observe HO2S bank 1 sensor 2 voltage. If voltage is less than 150 millivolts, go to step 8. If voltage is 150 millivolts or more, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Dark Green/White wire between terminal No. 51 at PCM C1 harness connector and terminal "B" at HO2S bank 1 sensor 2 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Dark Green/White wire. After repairs, go to step 13. If continuity exists, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Dark Blue/White wire between terminal No. 50 at PCM C1 harness connector and terminal "A" at HO2S bank 1 sensor 2 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Dark Blue/White wire. After repairs, go to step 13. If continuity exists, go to step 10.
9. Check for poor connections at HO2S bank 1 sensor 2 connector. Repair connector as necessary. After repairs, go to step 13. If connectors are okay, go to step 11.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to step 12.
11. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 2. After repairs, go to step 13.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

For intermittent conditions, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is 350-500 millivolts, go to step 4. If voltage is not 350-500 millivolts, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Check for exhaust leaks. Ensure HO2S bank 2 sensor 1 is installed correctly. Check for damaged HO2S bank 2 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan/White wire) and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan/White wire between terminal No. 54 at PCM C1 harness connector and terminal "A" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 55 at PCM C1 harness connector and terminal "B" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 2 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is less than 300 millivolts, go to step 4. If voltage is 300 millivolts or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S40916026672001091900000).
4. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S40916026672001091900000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check if Purple/White wire at terminal "B" at HO2S bank 2 sensor 1 harness connector is shorted to ground. (Scheme 2) Also check if Purple/White wire at terminal "B" is shorted to Tan/White wire at terminal "A" at HO2S bank 2 sensor 1 harness connector. If Purple/White wire is shorted to ground or shorted to Tan/White wire, repair wiring as necessary. After repairs, go to step 7. If wiring is okay, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too low will cause a lean condition. The PCM will compensate for some decrease in fuel pressure, but if fuel pressure is too low, DTC P0151 may set. Check fuel injectors. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If fuel injectors deliver improper fuel volume, DTC P0151 may set. Check for exhaust leaks. Exhaust leaks may cause outside air to be drawn into the exhaust gas stream, and pass the HO2S. This causes the HO2S signal to indicate a false lean condition. Check for Secondary Air Injection (AIR) system leaks. Check AIR system hoses, check valves, and piping for leaks. Check for poor connections or for signs of any damage. Check for disconnected or damaged vacuum hoses. Check for vacuum leaks at throttle body, EGR valve, EVAP purge solenoid, and intake manifold. Check for fuel contamination. Water, even in small amounts, can be delivered to fuel injectors. Water can cause a lean exhaust. Also, excessive alcohol in the fuel can cause a lean condition. Check with customer in order to verify conditions under which DTC set. Check if vehicle ran out of fuel. If none of the previous conditions are present, replace HO2S. Using scan tool, review front and rear long term fuel trim values fail records data. If both banks were lean, check for a condition that would cause a lean engine operation. If only rear bank was lean, the lean condition is isolated to that bank. Check for an intermittent short to ground on HO2S signal circuit. If condition is not present, check with customer about type of fuel used. Recommend using fuels of 10 percent or less ethanol.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions listed code enable criteria. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is more than 600 millivolts, go to step 4. If voltage is 600 millivolts or less, go to next step.
3. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S08482692582001091900000).
4. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 1 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is about 450 millivolts, see «DIAGNOSTIC AIDS»(ref-121492-S08482692582001091900000). If voltage is not about 450 millivolts, go to next step.
5. Turn ignition off and wait 30 seconds. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and terminal No. 55 (Purple/White wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Purple/White wire between PCM and HO2S bank 2 sensor 1. After repairs, go to step 7. If no voltage is indicated, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check HO2S wire routing. HO2S wiring may be routed incorrectly and contacting exhaust system. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too high will cause a rich condition. PCM will compensate for some increase in fuel pressure, but if fuel pressure is high enough, DTC P0152 may set. Check fuel injectors. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Check EVAP canister and hoses for fuel saturation. If fuel injectors deliver improper fuel volume, DTC P0152 may set. Check for silicone contamination. Silicone contamination of HO2S can also cause a high HO2S voltage signal. This condition is indicated by a powdery White deposit on tip of HO2S that is exposed to exhaust stream. Using scan tool, review front and rear long term fuel trim values fail records data. If both banks were rich, check for a condition that would cause a rich engine operation. If only front bank was rich, the rich condition is isolated to that bank. Check for an intermittent short to voltage on HO2S signal circuit.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If scan tool indicates HO2S voltage varying outside 325-625 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 325-625 millivolts, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S28194447592001091900000).
4. Check for exhaust leaks. Ensure HO2S bank 2 sensor 1 is installed correctly. Check for damaged HO2S bank 2 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan/White wire) and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan/White wire between terminal No. 54 at PCM C1 harness connector and terminal "A" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 55 at PCM C1 harness connector and terminal "B" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 2 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and for poor terminal-to-wire connections. Inspect wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to HO2S bank 2 sensor 1. A change in scan tool display will indicate malfunction location. Fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since diagnostic test last failed may help to diagnose condition. The information may help determine how often condition that set DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set except HO2S DTCs, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine. Ensure engine is at normal operating temperature. Increase engine speed to 1200 RPM for 2 minutes. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If scan tool indicates HO2S voltage varying outside 400-500 millivolts, go to next step. If scan tool does not indicate HO2S voltage varying outside 400-500 millivolts, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S27124238262001091900000).
4. Check for exhaust leaks. Ensure HO2S bank 2 sensor 1 is installed correctly. Check for damaged HO2S bank 2 sensor 1 wiring harness. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
5. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Measure voltage between ground and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. (Scheme 2) If voltage is about 450 millivolts, go to next step. If voltage is not about 450 millivolts, go to step 8.
6. Turn ignition off. Connect a jumper wire between terminal "A" (Tan/White wire) and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. Turn ignition on. Using scan tool, observe HO2S bank 2 sensor 1 voltage. If voltage is about zero volts, go to step 9. If voltage is not about zero volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Tan/White wire between terminal No. 54 at PCM C1 harness connector and terminal "A" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Tan/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Purple/White wire between terminal No. 55 at PCM C1 harness connector and terminal "B" at HO2S bank 2 sensor 1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Purple/White wire. After repairs, go to step 13. If continuity exists, go to step 11.
9. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to next step.
10. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 2 sensor 1. After repairs, go to step 13.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and for poor terminal-to-wire connections. Inspect wiring harness for damage. If harness appears to be okay, observe scan tool while moving connectors and wiring harnesses related to HO2S bank 2 sensor 1. A change in scan tool display will indicate malfunction location. Fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Reviewing failure records vehicle mileage since diagnostic test last failed may help to diagnose condition. The information may help determine how often condition that set DTC occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Observe DTC information for 30 seconds. If DTCs P0030, P1031 and P1032 are set, go to «DTC P0030: HO2S HEATER CONTROL CIRCUIT VOLTAGE IS GREATER THAN PCM INTERNAL DRIVER CAPACITY»(ref-121492-S24747406752001090400000). If DTCs P0030, P1031 and P1032 are not set, go to next step.
3. Start engine. Using scan tool, observe DTC information for 5 minutes. If P0135 and P0155 are set, go to «DTC P0135: HEATED OXYGEN SENSOR HEATER CIRCUIT - BANK 1 SENSOR 1»(ref-121492-S31267907532001082900000). If P0135 and P0155 are not set, go to next step.
4. If P0155 is set, go to next step. If P0155 is not set, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Remove fuse No. 20 (OXY SEN fuse) from underhood fuse block. Check continuity of Pink/Black wire between fuse holder output terminal for fuse No. 20 and terminal "D" at HO2S bank 2 sensor 1 harness connector. (Scheme 2) If continuity does not exist, repair open in Pink/Black wire. After repairs, go to step 12. If continuity exists, reinstall fuse and go to next step.
6. Turn ignition on. Measure voltage between ground and terminal "C" (Black/White wire) at HO2S bank 2 sensor 1 harness connector. If voltage is about 5 volts, go to step 8. If voltage is not about 5 volts, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black/White wire between terminal "C" at HO2S bank 2 sensor 1 harness connector and terminal No. 33 at PCM C1 harness connector. see scheme 2and (Scheme 2). If continuity does not exist, repair open in Black/White wire. After repairs, go to step 12. If continuity exists, go to step 9.
8. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 12. If connector is okay, go to step 10.
9. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 12. If connectors are okay, go to step 11.
10. Replace HO2S bank 2 sensor 1. After repairs, go to step 12.
11. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
12. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Do not solder HO2S wires. Soldering wires will result in loss of air reference to sensor.

An intermittent open in HO2S ignition signal circuit or ground circuit may cause DTC to set. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set, repair DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, record LONG TERM FUEL TRIM data. Turn ignition off. Turn ignition on. Using scan tool, review FREEZE FRAME RECORDS and/or FAILURE RECORDS and record data. If long term fuel trim is more than 23 percent, go to next step. If long term fuel trim is 23 percent or less, see «DIAGNOSTIC AIDS»(ref-121492-S34523648612001082900000).
3. Start engine and allow it to idle. Using scan tool, observe HO2S voltage. If voltage is 200-800 millivolts and fluctuating, go to next step. If voltage is not 200-800 millivolts or is not fluctuating, go to step 5.
4. Turn ignition off. Check vacuum hoses for splits, kinks and proper routing. Check for contaminated fuel. Ensure fuel tank has enough fuel. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too low will cause a lean condition. If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to step 6.
5. Turn ignition off. Ensure HO2S is installed correctly and wiring harness is not touching exhaust. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for continuity between terminal "A" (Tan wire) and terminal "B" (Purple/White wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) If continuity exists, Purple/White and Tan wires are shorted together. Repair wiring as necessary. After repairs, go to step 7. If continuity does not exist, diagnose fuel system. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
6. Operate engine at idle. Check for missing, loose, or leaking exhaust components. Check for vacuum leaks at intake manifold, throttle body and injector "O" rings. Check air induction system and air intake ducts for leaks. Check crankcase ventilation system for leaks. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, check engine mechanical condition and repair as necessary.
7. After repairs, using scan tool fuel trim reset function, reset long term fuel trim. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

System will go lean if an injector is not suppling enough fuel. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel. An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Do not attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set, repair DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .
2. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, record long term fuel trim data. Turn ignition off. Turn ignition on. Using scan tool, record LONG TERM FUEL TRIM data. Turn ignition off. Turn ignition on. Using scan tool, review FREEZE FRAME RECORDS and/or FAILURE RECORDS and record data. If long term fuel trim is less than -13 percent, go to next step. If long term fuel trim is -13 percent or more, see «DIAGNOSTIC AIDS»(ref-121492-S02007587382001082900000) .
3. Start engine and allow it to idle. Using scan tool, observe HO2S voltage. If voltage is 200-800 millivolts and fluctuating, go to next step. If voltage is not 200-800 millivolts or is not fluctuating, go to step 5 .
4. Turn ignition off. Check Mass Airflow (MAF) sensor inlet screen for blockage. Check vacuum hoses for splits, kinks and proper routing. Check for collapsed or restricted air intake duct. Check for restricted or dirty air filter. Check for throttle body blockage. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to step 6 .
5. Turn ignition off. Ensure HO2S is installed correctly and wiring harness is not touching exhaust. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, diagnose fuel system. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
6. Check for excessive fuel in crankcase. Check evaporative emissions control system. See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Check fuel pressure regulator for proper operation. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTICS article. Ensure all fuel injectors are functioning properly. Perform fuel injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, check engine mechanical condition and repair as necessary.
7. After repairs, using scan tool fuel trim reset function, reset long term fuel trim. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Fuel contamination, such as water or alcohol will affect fuel trim. A bad MAF/IAT sensor can cause a rich condition. Using scan tool, review failure records. If an intermittent condition is suspect, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set, repair DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
2. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, record long term fuel trim data. Turn ignition off. Turn ignition on. Using scan tool, record LONG TERM FUEL TRIM data. Turn ignition off. Turn ignition on. Using scan tool, review FREEZE FRAME RECORDS and/or FAILURE RECORDS and record data. If long term fuel trim is more than 23 percent, go to next step. If long term fuel trim is 23 percent or less, see «DIAGNOSTIC AIDS»(ref-121492-S41474036082001091900000).
3. Start engine and allow it to idle. Using scan tool, observe HO2S voltage. If voltage is 200-800 millivolts and fluctuating, go to next step. If voltage is not 200-800 millivolts or is not fluctuating, go to step 5.
4. Turn ignition off. Check vacuum hoses for splits, kinks and proper routing. Check for contaminated fuel. Ensure fuel tank has enough fuel. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too low will cause a lean condition. If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to step 6.
5. Turn ignition off. Ensure HO2S is installed correctly and wiring harness is not touching exhaust. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for continuity between terminal "A" (Tan/White wire) and terminal "B" (Purple/White wire) at HO2S bank 2 sensor 1 harness connector. (Scheme 2) If continuity exists, Purple/White and Tan/White wires are shorted together. Repair wiring as necessary. After repairs, go to step 7. If continuity does not exist, diagnose fuel system. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
6. Operate engine at idle. Check for missing, loose, or leaking exhaust components. Check for vacuum leaks at intake manifold, throttle body and injector "O" rings. Check air induction system and air intake ducts for leaks. Check crankcase ventilation system for leaks. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, check engine mechanical condition and repair as necessary.
7. After repairs, using scan tool fuel trim reset function to reset long term fuel trim. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

System will go lean if an injector is not suppling enough fuel. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel. An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Do not attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If any other DTCs are set, repair DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .
2. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, record long term fuel trim data. Turn ignition off. Turn ignition on. Using scan tool, record LONG TERM FUEL TRIM data. Turn ignition off. Turn ignition on. Using scan tool, review FREEZE FRAME RECORDS and/or FAILURE RECORDS and record data. If long term fuel trim is less than -13 percent, go to next step. If long term fuel trim is -13 percent or more, see «DIAGNOSTIC AIDS»(ref-121492-S36310823252001091900000) .
3. Start engine and allow it to idle. Using scan tool, observe HO2S voltage. If voltage is 200-800 millivolts and fluctuating, go to next step. If voltage is not 200-800 millivolts or is not fluctuating, go to step 5 .
4. Turn ignition off. Check vacuum hoses for splits, kinks and proper routing. Check for contaminated fuel. Ensure fuel tank has enough fuel. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure that is too low will cause a lean condition. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to step 6 .
5. Turn ignition off. Ensure HO2S is installed correctly and wiring harness is not touching exhaust. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, diagnose fuel system. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
6. Check for excessive fuel in crankcase. Check evaporative emissions control system. See FUEL EVAPORATION under EMISSION SYSTEMS & SUBSYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Check fuel pressure regulator for proper operation. See FUEL SYSTEMS in appropriate BASIC DIAGNOSTICS article. Ensure all fuel injectors are functioning properly. Perform fuel injector balance test. See FUEL INJECTOR BALANCE TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, check engine mechanical condition and repair as necessary.
7. After repairs, using scan tool fuel trim reset function, reset long term fuel trim. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Fuel contamination, such as water or alcohol will affect fuel trim. A bad MAF/IAT sensor can cause a rich condition. Using scan tool, review failure records. If an intermittent condition is suspect, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, record FREEZE FRAME and/or FAILURE RECORDS data for this DTC, then clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, observe misfire current counters. If any misfire current counters are incrementing, go to step 4 . If no misfire current counters are incrementing, go to next step.
3. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S11833942392001091900000) .
4. Turn ignition off. Disconnect fuel injector connector for DTC that is set. See «DIAGNOSTIC TROUBLE CODE IDENTIFICATION»(ref-121492-S31080095892001092400000) table. Turn ignition on. Using a test light connected to ground, probe ignition voltage circuit at suspect fuel injector harness connector. See «INJECTOR IGNITION VOLTAGE CIRCUIT IDENTIFICATION»(ref-121492-S21992492642001092100000) table. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 . DIAGNOSTIC TROUBLE CODE IDENTIFICATION DTC Injector No. P0201 (1) 1 P0202 2 P0203 3 P0204 4 P0205 5 P0206 6 P0207 7 P0208 8 (1) Injector No. 1 is the first injector on right (rear) rear cylinder head. INJECTOR IGNITION VOLTAGE CIRCUIT IDENTIFICATION Injector No. Wire Color 1 Pink/Black 2 Pink 3 Pink 4 Pink/White 5 Pink/Black 6 Pink 7 Pink 8 Pink
5. Connect Fuel Injector Test Light (J 34730-405) between suspect fuel injector harness connector. Start engine. If test light blinks, go to step 9 . If test light does not blink, go to next step.
6. If test light remains on at all times, go to step 8 . If test light does not remain on at all times, go to next step.
7. Check suspect fuel injector control circuit for short to voltage or open. See «INJECTOR CONTROL CIRCUIT IDENTIFICATION»(ref-121492-S33750656592001092100000) table. If any problems are found, repair wiring as necessary. After repairs, go to step 14 . If no problems are found, go to step 10 .
8. Using a test light connected to positive battery voltage, probe control circuit at suspect fuel injector harness connector. See «INJECTOR CONTROL CIRCUIT IDENTIFICATION»(ref-121492-S33750656592001092100000) table. If test light illuminates, repair short to ground in fuel injector control circuit. After repairs, go to step 14 . If test light does not illuminate, go to step 13 .
9. Check suspect fuel injector connector for poor connections. Repair connector as necessary. After repairs, go to step 14 . If no problem was found, go to step 12 .
10. Check PCM connectors for poor connections. PCM is located in engine compartment, inside air filter housing. Repair connectors as necessary. After repairs, go to step 14 . If connectors are okay, go to step 13 .
11. Repair open or short to ground in ignition voltage circuit between fuel injector and underhood fuse block. After repairs, go to step 14 .
12. Replace fuel injector. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. After repairs, go to step 14 .
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Performing fuel injector coil test may help isolate an intermittent condition. See FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If an intermittent condition is suspect, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

INJECTOR CONTROL CIRCUIT IDENTIFICATION

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, command fuel pump relay on and off. Listen for fuel pump relay operating noise. Fuel pump relay is located in rear fuse block. Rear fuse block is located underneath driver's side rear seat. If fuel pump relay turns on and off as commanded, go to next step. If fuel pump relay does not turn on and off as commanded, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Remove fuel pump relay. Turn ignition on. Using a test light connected to ground, probe fuel pump relay control circuit (Dark Green/White wire) at fuel pump relay connector. See WIRING DIAGRAMS article. Using scan tool, command fuel pump relay on and off. If test light turns on and off as commanded, disconnect test light and go to next step. If test light does not turn on and off as commanded, go to step 6.
5. Turn ignition off. Connect a test light between fuel pump relay control circuit (Dark Green/White wire) and fuel pump relay ground circuit (Black wire) at fuel pump relay connector. Turn ignition on. Using scan tool, command fuel pump relay on and off. If test light turns on and off as commanded, go to step 9. If test light does not turn on and off as commanded, go to step 11.
6. If test light is always on, go to step 8. If test light is always off, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in fuel pump relay control circuit (Dark Green/White wire) between fuel pump relay connector and terminal No. 70 at PCM C1 harness connector. see scheme 2 If Dark Green/White wire is open or shorted to ground, repair wiring as necessary. After repairs, go to step 14. If Dark Green/White wire is not open or shorted to ground, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to ground, probe terminal No. 70 (Dark Green/White wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, repair short to voltage in Dark Green/White wire between PCM and fuel pump relay connector. If test light does not illuminate, go to step 10.
9. Check fuel pump relay connector for poor connections. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 12.
10. Check PCM connectors for poor connections. PCM is located in engine compartment, inside air filter housing. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
11. Repair open in fuel pump relay ground circuit. See WIRING DIAGRAMS article. After repairs, go to step 14.
12. Replace fuel pump relay. After repairs, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Incorrect CKP system variation data in PCM may cause DTC to set with no apparent misfire. Any of the following conditions can cause incorrect CKP system variation data: Replace engine. Replacing PCM. Reprogramming PCM. Replacing CKP sensor. Performing internal engine repairs that affect CKP sensor-to-crankshaft reluctor wheel relationship. If none of the listed conditions apply to vehicle, go to next step. If any of the listed conditions apply to vehicle, CKP system variation learn procedure must be performed before continuing with misfire diagnosis. See «CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE»(ref-121492-S30360674422001083100000) under PROGRAMMING. NOTE: If any other DTCs are set, repair DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .
3. Start engine. Using scan tool, select MISFIRE BAR GRAPH or MISFIRE COUNTERS. If any cylinders indicate excessive misfire, go to next step. If no cylinders indicate excessive misfire, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. If misfire seems to be affecting specific cylinders, go to step 8 . If misfire is random to all cylinders, go to next step.
5. Turn ignition off. Check PCM and ignition control module grounds. See WIRING DIAGRAMS article. Ensure engine grounds are clean, tight and in their proper locations. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go to next step.
6. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. If fuel pressure is not as specified, repair fuel system as necessary. After repairs, go to step 13 . If fuel pressure is as specified, go to next step.
7. Check for fuel contamination. Water, even in small amounts, can be delivered to fuel injectors. Water can cause a lean exhaust. Also, excessive alcohol in the fuel can cause a lean condition. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go next step.
8. Operate engine at idle. Check for vacuum leaks at intake manifold, throttle body and injector "O" rings. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go to next step.
9. Perform fuel injector balance test and fuel injector coil test. See FUEL INJECTOR BALANCE TEST and FUEL INJECTOR COIL TEST under FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go to next step.
10. Check ignition system operation. See ELECTRONIC IGNITION SYSTEM DIAGNOSIS in appropriate SYSTEM & COMPONENT TESTING article. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go to next step.
11. Check for the following mechanical conditions: Damaged accessory drive belt or pulley. Damaged driven accessory (generator, water pump, drive belt tensioner, etc.). Loose or broke motor mount. Engine mechanical problems. If any problems are found, repair as necessary. After repairs, go to step 13 . If no problems are found, go to next step.
12. Ensure transaxle torque converter clutch is functioning properly. See appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Using scan tool, perform CKP system variation learn procedure. See CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE under PROGRAMMING. Ensure all connections are clean and properly tightened. A damaged serpentine belt or belt driven accessory can cause engine load variations sufficient to set a misfire DTC. Check fuel pressure. See appropriate BASIC DIAGNOSTIC PROCEDURES article. A malfunctioning fuel pump, a plugged filter, or a malfunctioning fuel system pressure regulator will contribute to a lean condition. Performing fuel injector coil test. See FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Check for contaminated fuel. Excessive open loop operation caused by extended idling or short trip driving may leave deposits on heated oxygen sensors. Deposits cause oxygen sensors to respond slowly to exhaust oxygen content, affecting fuel control and causing a misfire to be indicated at idle. This condition is not permanent. In order to determine if this condition is causing DTC P0300 to be set, review FREEZE FRAME/FAILURE RECORDS for DTC P0300. If DTC P0300 occurs at high engine speeds, the condition described did not cause DTC P0300 to set. If DTC P0300 occurs at idle or very low engine speeds and at engine coolant temperatures less than 176°F (80°C), the condition described is very likely the cause of the DTC P0300 being set. The deposits on the heated oxygen sensors can be eliminated by operating vehicle fully warm at mass airflows more than 15 grams/sec. DTC may set if vehicle misfires while running out of fuel. If no misfire is currently present, but history counters indicate random misfire was once present, ask customer if vehicle has run out of fuel. If this is the case, no further repair may be necessary.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to next step.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to step 2 . If DTC runs and passes, go to next step.
5. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for loose engine accessory or accessory bracket. If any problems are found, repair as necessary. After repairs, go to step 4 . If no problems are found, go to next step.
3. Start engine. Check for excessive mechanical noise. If any problems are found, repair as necessary. After repairs, go to step 4 . If no problems are found, fault may be intermittent. See TROUBLE SHOOTING - NO CODES article.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to step 2 . If DTC runs and passes, go to next step.
5. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe and record the FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Disconnect knock sensor/starter solenoid 3-pin connector. Connector is located on right side of engine compartment, near rear corner of intake manifold. Set DVOM to 400 mV AC scale. Check frequency at Dark Blue and Gray wires at knock sensor/starter solenoid harness connector (component side). Tap on engine block with a non-metallic object. If frequency fluctuates while tapping block, go to next step. If frequency does not fluctuate, go to step 5.
4. Turn ignition on. Using scan tool, save FREEZE FRAME & FAILURE RECORDS data stored when DTC was set. Turn ignition off. Reconnect knock sensor/starter solenoid connector. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Check frequency between terminals No. 19 (Dark Blue wire) and No. 35 (Gray wire) at PCM C2 harness connector. see scheme 2 If frequency fluctuates while tapping on block, go to step 7. If frequency does not fluctuate, go to next step 6.
5. Ensure ignition is off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Remove intake manifold to access knock sensor. See REMOVAL & INSTALLATION in appropriate article in ENGINES. Disconnect knock sensor connector. Check knock sensor signal circuit (Dark Blue wire) and knock sensor ground circuit (Gray wire) as follows: Check for open or short to ground in Dark Blue wire between knock sensor harness connector and knock sensor/starter solenoid connector. Check for continuity between Dark Blue and Gray wires at knock sensor harness connector. Continuity should not exist. If continuity exists, Dark Blue and Gray wires are shorted together. Check continuity of Gray wire between knock sensor harness connector and knock sensor/starter solenoid connector. Continuity should exist. If continuity does not exist, Gray wire is open. Turn ignition on. Connect a test light between ground and Dark Blue wire at knock sensor harness connector. Test light should not illuminate. If test light illuminates, Dark Blue wire is shorted to voltage. Check knock sensor connector for poor connections. If any problems are found, repair as necessary. After repairs, go to step 10. If no problems are found, go to step 8
6. Disconnect knock sensor/starter solenoid connector. Ensure PCM is disconnected. Check knock sensor signal circuit (Dark Blue wire) and knock sensor ground circuit (Gray wire) as follows: Check for open or short to ground in Dark Blue wire between knock sensor/starter solenoid connector and terminal No. 19 at PCM C2 harness connector. see scheme 2 Check for continuity between terminals No. 19 (Dark Blue wire) and No. 35 (Gray wire) at PCM C2 harness connector. Continuity should not exist. If continuity exists, Dark Blue and Gray wires are shorted together. Check continuity of Gray wire between knock sensor/starter solenoid connector and terminal No. 35 at PCM C2 harness connector. Continuity should exist. If continuity does not exist, Gray wire is open. Turn ignition on. Using a test light connected to ground, probe terminal No. 35 (Gray wire) at PCM C2 harness connector. Test light should not illuminate. If test light illuminates, Gray wire is shorted to voltage. Check knock sensor/starter solenoid connector for poor connections. Repair as necessary. After repairs, go to step 10.
7. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 10. If connectors are okay, go to step 9.
8. Replace knock sensor. After repairs, go to step 10.
9. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 3.
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If condition is intermittent, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. Ignition system DTCs set with ignition switch in START position if starter relay or starter is inoperative. When PCM enables starter operation, the PCM also initiates diagnostic test routines for DTCs P0335, P0340, and P0385. The PCM will not receive signal input from CKP and CMP sensors if a condition exists which prevents engine from cranking. When this occurs, DTCs will set. If DTC P0615 is set, diagnose DTC P0615 first. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS. If DTC P0335, P0340, and/or P0385 are set and no problem is found, check if there is a no-crank condition or an intermittent no-crank condition. Check if an attempt was made to crank engine with shift lever not in Park or Neutral.

When diagnosing CKP sensors, it may be necessary to enable a specific decode mode (ANGLE, TIME A or TIME B). In order to enable a specific crank decode, use scan tool and perform the following

1. Turn ignition on.
2. Select ENGINE OUTPUT CONTROLS.
3. Select CRANK POSITION SENSING DECODE mode.
4. Select desired mode (ANGLE, TIME A or TIME B) by pressing SELECT STATE.
5. Command decode mode by pressing COMMAND STATE.

The commanded state remains valid for current ignition cycle. A specific decode mode cannot be commanded with engine running, or after commanding a desired decode mode. In order to command a different decode mode, ignition must be cycled off and on.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If DTC P0385 is also set, repair DTC before continuing with this test. See «DTC P0385: CRANKSHAFT POSITION SENSOR "B" CIRCUIT»(ref-121492-S05248220742001092400000)
2. Ensure ignition is on. Raise and support vehicle. Disconnect CKP sensor "A" connector. see scheme 7 Check for an intermittent open or short to ground in 12-volt reference circuit (Light Green wire) between terminal "A" at CKP sensor "A" harness connector and terminal No. 65 at PCM C2 harness connector. see scheme 2and see scheme 8. Also check for poor connections at CKP sensor "A"connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
3. Check for an intermittent open in low reference circuit (Yellow/Black wire) between terminal "B" at CKP sensor "A" harness connector and terminal No. 66 at PCM C2 harness connector. Also check for poor terminal contact at CKP sensor "A". If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
4. Check CKP "A" signal circuit (Light Blue/White wire) for intermittent open, intermittent short to 12-volt reference circuit (Light Green wire), intermittent short to battery voltage, intermittent short to ground or intermittent short to low reference circuit (Yellow/Black wire) at CKP sensor "A" harness connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
5. Check for poor terminal contact at terminal No. 2 (Light Blue wire) at PCM C1 harness connector. see scheme 2 Also check for poor terminal contact at terminals No. 65 (Light Green wire) and No. 66 (Yellow/Black wire) at PCM C2 harness connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, see «DIAGNOSTIC AIDS»(ref-121492-S29998332252001091900000).
6. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, observe and record the FREEZE FRAME/FAILURE RECORDS data for this DTC. Clear DTCs. Using scan tool, command system to operate in TIME A mode. See «DIAGNOSTIC AIDS»(ref-121492-S29998332252001091900000) for assistance on selecting crank position sensing decode mode. Monitor SPECIFIC DTC INFO for this DTC. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

When diagnosing CKP sensors, it may be necessary to enable a specific decode mode (ANGLE, TIME A or TIME B). In order to enable a specific crank decode, use scan tool and perform the following

1. Turn ignition on.
2. Select ENGINE OUTPUT CONTROLS.
3. Select CRANK POSITION SENSING DECODE mode.
4. Select desired mode (ANGLE, TIME A or TIME B) by pressing SELECT STATE.
5. Command decode mode by pressing COMMAND STATE.

The commanded state remains valid for current ignition cycle. A specific decode mode cannot be commanded with engine running, or after commanding a desired decode mode. In order to command a different decode mode, ignition must be cycled off and on.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Attempt to start engine. Using scan tool, monitor DTC information. If DTC P0335, P0340 and P0385 are all set, go to step 9. If DTC P0335, P0340 and P0385 are all not set, go to next step.
3. Ensure engine is running. Using scan tool, monitor DTC information. If DTC P0340 runs and passes, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If DTC P0340 resets, go to next step.
4. Disconnect CMP sensor connector. CMP sensor is located in front of right (rear) cylinder head. Turn ignition on. Connect a test light between Red and Pink/Black wires at CMP sensor harness connector. If test light does not illuminate, go to next step. If test light illuminates, go to step 6.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM connectors. Repair connectors as necessary. If connectors are okay, check continuity of Red wire between CMP sensor harness connector and terminal No. 58 at PCM C1 harness connector. see scheme 2 Also, check continuity of Pink/Black wire between CMP sensor harness connector and terminal No. 67 at PCM C2 harness connector. If both readings indicate continuity exists, go to step 16. If either reading indicates continuity does not exist, repair open in Red or Pink/Black wire wire. After repairs, go to step 17.
6. Ensure ignition is on. Using a test light connected to positive battery voltage, repeatedly touch Orange wire at CMP sensor harness connector. Using scan tool, observe CMP sensor display. If scan tool indicates an RPM when touching Orange wire, go to step 8. If scan tool does not indicate an RPM when touching Orange wire, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM connectors. Repair connectors as necessary. If connectors are okay, turn ignition on. Check CMP sensor high resolution sensor circuit (Orange wire) as follows: Check for open or short to ground in Orange wire between CMP sensor harness connector and terminal No. 1 at PCM C1 harness connector. see scheme 2 Check for continuity between Orange and Red wires at CMP sensor harness connector. Continuity should not exist. If continuity exists, Orange and Red wires are shorted together. Check for continuity between Orange and Pink/Black wires at CMP sensor harness connector. Continuity should not exist. If continuity exists, Orange and Pink/Black wires are shorted together. Turn ignition on. Using a test light connected to ground, probe terminal No. 1 (Orange wire) at PCM C1 harness connector. Test light should not illuminate. If test light illuminates, Orange wire is shorted to voltage. If any problems are found, repair as necessary. After repairs, go to step 17. If no problems are found, go to step 16.
8. Check for poor connections at CMP sensor connector. Repair connector as necessary. After repairs, go to step 17. If connector is okay, go to step 13.
9. Disconnect CMP sensor connector. CMP sensor is located in front of right (rear) cylinder head. Turn ignition on. Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 13. If scan tool does not display OK, go to next step.
10. Raise and support vehicle. Disconnect CKP sensor "A" connector. see scheme 7 Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 14. If scan tool does not display OK, go to next step.
11. Disconnect CKP sensor "B" connector. Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 15. If scan tool does not display OK, go to next step.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Ensure CKP sensor "A", CKP sensor "B" and CMP sensor are disconnected. Check 12-volt reference circuits for a short to ground as follows: Using a test light connected to battery voltage, probe terminal No. 65 (Light Green wire) at PCM C2 harness connector. see scheme 2 Test light should not illuminate. If test light illuminates, Light Green wire is shorted to ground between PCM and CKP sensor "A". Using a test light connected to battery voltage, probe terminal No. 25 (Light Green wire) at PCM C2 harness connector. Test light should not illuminate. If test light illuminates, Light Green wire is shorted to ground between PCM and CKP sensor "B". Using a test light connected to battery voltage, probe terminal No. 58 (Red wire) at PCM C1 harness connector. Test light should not illuminate. If test light illuminates, Red wire is shorted to ground between PCM and CMP sensor. Repair wiring as necessary. After repairs, go to step 17.
13. Replace CMP sensor. After repairs, go to step 17.
14. Replace CKP sensor "A". After repairs, go to step 17.
15. Replace CKP sensor "B". After repairs, go to step 17.
16. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
17. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, check if DTC P0340 is also set. If DTC P0340 is set, go to next step. If DTC P0340 is not set, go to step 7.
3. Check for an intermittent open in 12-volt reference circuit (Red wire) between terminal "C" at CMP sensor harness connector and terminal No. 58 at PCM C1 harness connector. see scheme 2and see scheme 8. CMP sensor is located in front of right (rear) cylinder head. PCM is located in engine compartment, inside air filter housing. Also check for poor connections at PCM and CMP sensor connectors. Repair connectors as necessary. After repairs, go to step 8. If connectors are okay, go to next step.
4. Check for an intermittent open or short to ground in high resolution signal circuit (Orange wire) between terminal "A" at CMP sensor harness connector and terminal No. 1 at PCM C1 harness connector. Check for an intermittent short between terminal "A" (Orange wire) and terminal "C" (Red wire) at CMP sensor harness connector. Also check for poor connections at PCM and CMP sensor connectors. If any problems are found, repair as necessary. After repairs, go to step 8. If no problems are found, go to next step.
5. Check for an intermittent open in low reference circuit (Pink/Black wire) between terminal "B" at CMP sensor harness connector and terminal No. 67 at PCM C2 harness connector. If any problems are found, repair as necessary. After repairs, go to step 8. If no problems are found, go to next step.
6. Check CMP harness wiring for improper routing near high frequency devices. Repair as necessary. After repairs, go to step 8. If routing is okay, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
7. Check valve train for damage or misaligned camshaft timing components. Check for proper camshaft timing. See appropriate article in ENGINES. Repair as necessary. After repairs, go to next step. If no problem is found, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 1, go to next step. If misfire counters do not increment for cylinder No. 2, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect rear ICM connector. Rear ICM is located on right (rear) valve cover. Using a test light connected to positive battery voltage, probe terminal "F" (Purple wire) at rear ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Purple wire between terminal "F" at rear ICM harness connector and terminal No. 61 at PCM C1 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Scheme 4

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 2, go to next step. If misfire counters do not increment for cylinder No. 2, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect front ICM connector. Front ICM is located on left (front) valve cover. Using a test light connected to positive battery voltage, probe terminal "G" (Red/White wire) at front ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Red/White wire between terminal "G" at front ICM harness connector and terminal No. 22 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 3, go to next step. If misfire counters do not increment for cylinder No. 3, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect rear ICM connector. Rear ICM is located on right (rear) valve cover. Using a test light connected to positive battery voltage, probe terminal "E" (Light Blue wire) at rear ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Light Blue wire between terminal "E" at rear ICM harness connector and terminal No. 21 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 4, go to next step. If misfire counters do not increment for cylinder No. 4, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect front ICM connector. Front ICM is located on left (front) valve cover. Using a test light connected to positive battery voltage, probe terminal "D" (Dark Green/White wire) at front ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Dark Green/White wire between terminal "D" at front ICM harness connector and terminal No. 59 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 5, go to next step. If misfire counters do not increment for cylinder No. 5, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect rear ICM connector. Rear ICM is located on right (rear) valve cover. Using a test light connected to positive battery voltage, probe terminal "D" (Dark Green wire) at rear ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Dark Green wire between terminal "D" at rear ICM harness connector and terminal No. 62 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 6, go to next step. If misfire counters do not increment for cylinder No. 6, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect front ICM connector. Front ICM is located on left (front) valve cover. Using a test light connected to positive battery voltage, probe terminal "E" (Light Blue/White wire) at front ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Light Blue/White wire between terminal "E" at front ICM harness connector and terminal No. 60 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 7, go to next step. If misfire counters do not increment for cylinder No. 7, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect rear ICM connector. Rear ICM is located on right (rear) valve cover. Using a test light connected to positive battery voltage, probe terminal "G" (Red wire) at rear ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Red wire between terminal "G" at rear ICM harness connector and terminal No. 22 at PCM C1 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, select MISFIRE COUNTERS. If misfire counters increment for cylinder No. 8, go to next step. If misfire counters do not increment for cylinder No. 8, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Turn ignition off. Disconnect front ICM connector. Front ICM is located on left (front) valve cover. Using a test light connected to positive battery voltage, probe terminal "F" (Purple/White wire) at front ICM harness connector. (Scheme 4) If test light illuminates, go to next step. If test light does not illuminate, go to step 6.
4. Observe test light and disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. If test light is still illuminated, go to next step. If test light is not illuminated, go to step 7.
5. Repair short to ground in Purple/White wire between terminal "F" at front ICM harness connector and terminal No. 61 at PCM C2 harness connector. see scheme 2and (Scheme 4). After repairs, go to step 8.
6. Replace rear ICM. After repairs, go to step 8.
7. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Attempt to start engine. Using scan tool, monitor DTC information. If DTC P0335, P0340 and P0385 are all set, go to step 11. If DTC P0335, P0340 and P0385 are all not set, go to next step. NOTE: If DTC P0336 is also set, continue with this test before diagnosing DTC P0336.
3. Start engine. Using scan tool, monitor CKP sensor status parameter. If scan tool indicates CKP sensor status as ANGLE, go to next step. If scan tool does not indicate CKP sensor status as ANGLE, turn ignition off and go to step 5.
4. Ensure engine is running. Observe scan tool and wiggle CKP sensor "B" wiring harness. see scheme 7 If CKP sensor status changes or engine stalls, a fault exists in CKP sensor "B" wiring harness or connector. Repair as necessary. After repairs, go to step 21. If CKP sensor status doe not change and engine does not stall, see «DIAGNOSTIC AIDS»(ref-121492-S42065982602001092600000).
5. Turn ignition on. Raise and support vehicle. Disconnect CKP sensor "B" connector. see scheme 7 Using a test light connected to ground, probe terminal "A" (Light Green wire) at CKP sensor "B" harness connector. see scheme 8 If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
6. Connect test light between terminal "A" (Light Green wire) and terminal "B" (Yellow wire) at CKP sensor "B" harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 9.
7. Using scan tool, clear DTCs. Using scan tool, command PCM to operate in TIME B mode. Using a test light connected to positive battery voltage, repeatedly touch terminal "C" (Yellow wire) at CKP sensor "B" harness connector. Observe 24X crank sensor data on scan tool. If scan tool indicates an RPM when touching Yellow wire, go to step 15. If scan tool does not indicate an RPM when touching Yellow wire, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Light Green wire between terminal "A" at CKP sensor "B" harness connector and terminal No. 25 at PCM C2 harness connector. see scheme 2and see scheme 8. If continuity exists, go to step 16. If continuity does not exist, repair open in Light Green wire. After repairs, go to step 21.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Yellow wire between terminal "B" at CKP sensor "B" harness connector and terminal No. 28 at PCM C2 harness connector. see scheme 2and see scheme 8. If continuity exists, go to step 16. If continuity does not exist, repair open in Yellow wire. After repairs, go to step 21.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Check CKP sensor "B" signal circuit (Yellow wire) as follows: Check for open or short to ground in Yellow wire between terminal "C" at CKP sensor "B" harness connector and terminal No. 14 at PCM C1 harness connector. Check for continuity between terminal "B" (Yellow wire) and terminal "C" (Yellow wire) at CKP sensor "B" harness connector. Continuity should not exist. If continuity exists, Yellow wires are shorted together. Check for continuity between terminals No. 2 (Light Blue/White wire) and No. 14 (Yellow wire) at PCM C1 harness connector. Continuity should not exist. If continuity exists, Light Blue/White and Yellow wires are shorted together. Turn ignition on. Connect a test light between ground and terminal No. 14 (Yellow wire) at PCM C1 harness connector. Test light should not illuminate. If test light illuminates, Yellow wire is shorted to voltage. If any problems are found, repair as necessary. After repairs, go to step 21. If no problems are found, go to step 16.
11. Disconnect CMP sensor connector. CMP sensor is located in front of right (rear) cylinder head. Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 17. If scan tool does not display OK, go to next step.
12. Raise and support vehicle. Disconnect CKP sensor "A" connector. see scheme 7 Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 18. If scan tool does not display OK, go to next step.
13. Raise and support vehicle. Disconnect CKP sensor "B" connector. see scheme 7 Using scan tool, monitor 12-volt reference parameter. If scan tool displays OK, go to step 19. If scan tool does not display OK, go to next step.
14. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Ensure CKP sensor "A", CKP sensor "B" and CMP sensor are disconnected. Check 12-volt reference circuits for a short to ground as follows: Using a test light connected to battery voltage, probe terminal No. 65 (Light Green wire) at PCM C2 harness connector. see scheme 2 Test light should not illuminate. If test light illuminates, Light Green wire is shorted to ground between PCM and CKP sensor "A". Using a test light connected to battery voltage, probe terminal No. 25 (Light Green wire) at PCM C2 harness connector. Test light should not illuminate. If test light illuminates, Light Green wire is shorted to ground between PCM and CKP sensor "B". Using a test light connected to battery voltage, probe terminal No. 58 (Red wire) at PCM C1 harness connector. Test light should not illuminate. If test light illuminates, Red wire is shorted to ground between PCM and CMP sensor. If any problems are found, repair as necessary. After repairs, go to step 21. If no problems are found, go to step 20.
15. Check for poor connections at CKP sensor "B" connector. Repair connector as necessary. After repairs, go to step 21. If connector is okay, go to step 19.
16. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 21. If connectors are okay, go to step 20.
17. Replace CMP sensor. After repairs, go to step 21.
18. Replace CKP sensor "A". After repairs, go to step 21.
19. Replace CKP sensor "B". After repairs, go to step 21.
20. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
21. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
22. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If starter relay is inoperative or if starter is inoperative, ignition systems DTCs set with ignition switch in START position. When PCM enables starter operation, PCM also initiates diagnostic test routines for DTCs P0335, P0340 and P0385. If a condition exists which prevents engine from cranking, PCM will not receive the signal input from CKP sensors and CMP sensor, and DTCs will set. If DTC P0615 is set, diagnose DTC P0615 first. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS. If DTC P0335, P0340 and/or P0385 is set and no problem is found, check for no-crank or intermittent no-crank condition. Also check if an attempt to crank engine with shift lever not in Park or Neutral.

When diagnosing CKP sensors, it may be necessary to enable a specific decode mode (ANGLE, TIME A or TIME B). In order to enable a specific crank decode, use scan tool and perform the following

1. Turn ignition on.
2. Select ENGINE OUTPUT CONTROLS.
3. Select CRANK POSITION SENSING DECODE mode.
4. Select desired mode (ANGLE, TIME A or TIME B) by pressing SELECT STATE.
5. Command decode mode by pressing COMMAND STATE.

The commanded state remains valid for the current ignition cycle. A specific decode mode cannot be commanded with engine running, or after commanding a desired decode more. In order to command a different decode mode, ignition must be cycled off and on.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If DTC P0335 is also set, repair DTC before continuing with this test. See «DTC P0335: CRANKSHAFT POSITION SENSOR "A" CIRCUIT»(ref-121492-S21595802402001091900000).
2. Ensure ignition is on. Raise and support vehicle. Disconnect CKP sensor "B" connector. see scheme 7 Check for an intermittent open or short to ground in 12-volt reference circuit (Light Green wire) between terminal "A" at CKP sensor "B" harness connector and terminal No. 25 at PCM C2 harness connector. see scheme 2and see scheme 8. Also check for poor connections at CKP sensor "B"connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
3. Check for an intermittent open in low reference circuit (Yellow wire) between terminal "B" at CKP sensor "B" harness connector and terminal No. 28 at PCM C2 harness connector. Also check for poor terminal contact at CKP sensor "B". If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
4. Check CKP "B" signal circuit (Yellow wire) for intermittent open, intermittent short to 12-volt reference circuit (Light Green wire), intermittent short to battery voltage, intermittent short to ground or intermittent short to low reference circuit (Yellow wire) at CKP sensor "B" harness connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, go to next step.
5. Check for poor terminal contact at terminal No. 14 (Yellow wire) at PCM C1 harness connector. see scheme 2 Also check for poor terminal contact at terminals No. 25 (Light Green wire) and No. 28 (Yellow wire) at PCM C2 harness connector. If any problems are found, repair as necessary. After repairs, go to step 6. If no problems are found, see «DIAGNOSTIC AIDS»(ref-121492-S12981999482001092600000).
6. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

When diagnosing CKP sensors, it may be necessary to enable a specific decode mode (ANGLE, TIME A or TIME B). In order to enable a specific crank decode, use scan tool and perform the following

1. Turn ignition on.
2. Select ENGINE OUTPUT CONTROLS.
3. Select CRANK POSITION SENSING DECODE mode.
4. Select desired mode (ANGLE, TIME A or TIME B) by pressing SELECT STATE.
5. Command decode mode by pressing COMMAND STATE.

The commanded state remains valid for the current ignition cycle. A specific decode mode cannot be commanded with engine running, or after commanding a desired decode more. In order to command a different decode mode, ignition must be cycled off and on.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If any MAP DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If no MAP DTCs are set, go to next step.
3. Check exhaust system for leaks and modification of original parts. If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to next step.
4. Check EGR valve gasket and pipes for leaks. see scheme 5 If any problems are found, repair EGR system as necessary. After repairs, go to step 7. If no problems are found, go to next step.
5. Remove EGR valve. Check EGR valve pintle and passages for leaks and/or restrictions. If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to next step.
6. Remove EGR inlet and outlet pipes from intake and exhaust manifolds. Inspect manifold EGR ports, inlet pipes and outlet pipes for blockage/damage. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, see «DIAGNOSTIC AIDS»(ref-121492-S38854611522001092600000).
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If EGR valve shows signs of excessive heat, check exhaust system for blockage or for a plugged catalytic converter. A vacuum restriction to the MAP sensor can cause EGR flow test to fail due to insufficient MAP changes being monitored during the test. An engine that is running poorly may cause this DTC to set. Check for poor connection or damaged wiring harness. If wiring harness appears to be okay, observe EGR position sensor display on scan tool while moving connectors and wiring harnesses that are related to EGR valve. A change in the display indicates location of malfunction.

In order to verify a repair, select CLEAR INFO on scan tool, and run EGR flow test, keeping the following conditions in mind

1. PCM will only run EGR flow test during a gradual deceleration.
2. PCM will only run EGR test during a closed throttle condition.
3. PCM will only run EGR test with vehicle speeds at more than 37 MPH.
4. Several deceleration cycles will be necessary in order to run a sufficient number of EGR flow test samples. A sufficient number of samples is usually 5-15 samples.
5. If within enabling RPM (700-1200 RPM) engine speed decreases more than 500 RPM, PCM will reset test.
6. If within enabling RPM (700-1200 RPM) engine speed increases more than 75 RPM, PCM will reset test.
7. When PCM commands EGR valve open, engine speed will decrease. If engine speed decreases to less than 500 RPM, test will not run.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If DTC P0403 or P0405 is set, diagnose affected DTC(s) first. See «DTC P0403: EXHAUST GAS RECIRCULATION SOLENOID CONTROL CIRCUIT»(ref-121492-S33766380412001092600000) or «DTC P0405: EXHAUST GAS RECIRCULATION POSITION SENSOR CIRCUIT LOW VOLTAGE»(ref-121492-S22459489372001082900000).
2. Ensure ignition is on. Using scan tool, command EGR valve from zero to 100 percent. If EGR position sensor remains within 8 percent of desired EGR position at all commanded positions, go to next step. If EGR position sensor does not remain within 8 percent of desired EGR position at all commanded positions, go to step 4.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S14197317862001092600000).
4. Turn ignition off. Disconnect EGR valve connector. see scheme 5 Turn ignition on. Using a test light connected to ground, probe terminal "E" (Red wire) at EGR valve harness connector. see scheme 10 Using scan tool, command EGR 0-10 percent. If test light turns on and off with each command, go to next step. If test light does not turn on and off with each command, go to step 13.
5. Turn ignition off, then back on. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is zero percent, go to next step. If EGR position is not zero percent, go to step 9.
6. Measure voltage between terminal "B" (Black wire) and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 8.
7. Connect a 3-amp fused jumper wire between terminal "D" (Gray/Black wire) and terminal "C" (Brown wire) at EGR valve harness connector. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is about 100 percent, go to step 14. If EGR position is not about 100 percent, go to step 11.
8. Measure voltage between ground and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to step 10. If voltage is not about 5 volts, go to step 12.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal "C" (Brown wire) at EGR valve harness connector. If any voltage is indicated, repair short to voltage in Brown wire between EGR valve and PCM. After repairs, go to step 18. If no voltage is indicated, go to step 15.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black wire between terminal "B" at EGR valve harness connector and terminal No. 12 at PCM C2 harness connector. see scheme 2and see scheme 10. If continuity does not exist, repair open in Black wire. After repairs, go to step 18. If continuity exists, go to step 15.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal "C" (Brown wire) at EGR valve harness connector. see scheme 10 If test light illuminates, repair short to ground in Brown wire between EGR valve and PCM. After repairs, go to step 18. If test light does not illuminate, go to step 15.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check 5-volt reference circuit (Gray/Black wire wire) as follows: Check for open or short to ground in Gray/Black wire between terminal "D" at EGR valve harness connector and terminal No. 50 at PCM C2 harness connector. see scheme 2and see scheme 10. Turn ignition on. Using a test light connected to ground, probe terminal No. 50 (Gray/Black wire) at PCM C2 harness connector. Test light should not illuminate. If test light illuminates, Gray/Black wire is shorted to voltage. If any problems are found, repair as necessary. After repairs, go to step 18. If no problems are found, go to step 15.
13. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal "E" (Red wire) at EGR valve harness connector. see scheme 10 If test light illuminates, repair short to ground in Red wire between EGR valve and PCM. After repairs, go to step 18. If test light does not illuminate, go to step 15.
14. Check for poor connections at EGR valve connector. Repair connector as necessary. After repairs, go to step 18. If connector is okay, go to step 16.
15. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 18. If connectors are okay, go to step 17.
16. Replace EGR valve. After repairs, go to step 18.
17. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
18. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
19. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Remove EGR valve and inspect for deposits that may interfere with EGR valve pintle extending completely or cause pintle to stick. If problem is intermittent, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: If DTC P1635 is set, diagnose DTC before continuing with this test. See «DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT»(ref-121492-S40727140912001082900000).
2. Ensure ignition is on. Using scan tool, observe EGR valve position sensor voltage. If voltage is less than.11 volt, go to step 4. If voltage is.11 volt or more, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault my be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect EGR valve connector. see scheme 5 Connect a 3-amp fused jumper wire between terminal "C" (Brown wire) and terminal "D" (Gray/Black wire) at EGR valve harness connector. Turn ignition on. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is about 100 percent, remove jumper wire and go to step 10. If EGR position is not about 100 percent, remove jumper wire and go to next step.
5. Measure voltage between ground and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to step 9. If voltage is not about 5 volts, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Gray/Black wire between terminal "D" at EGR valve harness connector and terminal No. 50 at PCM C2 harness connector. see scheme 2and see scheme 10. If continuity does not exist, repair open in Gray/Black wire. After repairs, go to step 15. If continuity exists, go to next step.
7. Using a test light connected to positive battery voltage, probe terminal No. 50 (Gray/Black wire) at PCM C2 harness connector. see scheme 2 If test light illuminates, repair short to ground in Gray/Black wire between PCM and EGR valve. After repairs, go to step 15. If test light does not illuminate, go to next step.
8. Ensure ignition is off. Reconnect PCM connectors. Connect DVOM between terminal "B" (Black wire) and terminal "D" (Gray/Black wire) at EGR valve harness connector. Observe DVOM and disconnect Throttle Position (TP) sensor, and then Manifold Absolute Pressure (MAP) sensor. A voltage change indicates a faulty sensor. If any problems are found, replace TP sensor or MAP sensor as necessary. After repairs, go to step 15. If no problems are found, go to step 11.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in EGR valve position signal circuit (Brown wire) between terminal "C"at EGR valve harness connector and terminal No. 52 at PCM C2 harness connector. see scheme 2and see scheme 10. If any problems are found, repair as necessary. After repairs, go to step 15. If no problems are found, go to step 11.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for continuity between terminal "C" (Brown wire) and terminal "E" (Red wire) at EGR valve harness connector. If continuity exists, Brown wire is shorted to Red wire. Repair wiring as necessary. After repairs, go to step 15. If continuity does not exist, go to step 12.
11. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 15. If connectors are okay, go to step 14.
12. Check for poor connections at EGR valve connector. Repair connector as necessary. After repairs, go to step 15. If connector is okay, go to step 13.
13. Replace EGR valve. After repairs, go to step 15.
14. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
15. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
16. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0412, P1415 or P1416 is also set, repair DTC before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If DTC P0412, P1415 or P1416 is not set, go to next step.
3. Check for disconnected or damaged vacuum lines to AIR solenoid and each AIR shutoff valve. Check for switched vacuum lines at AIR solenoid. (Scheme 5) If any problems are found, repair as necessary. After repairs, go to step 8. If no problems are found, go to next step. NOTE: AIR solenoid may also be referred to as AIR by-pass valve solenoid or AIR vacuum control solenoid valve.
4. Connect vacuum gauge to engine. Start engine. If vacuum is more than 12 in. Hg, go to next step. If vacuum is 12 in. Hg or less, go to step 6.
5. Check for plugged, disconnected or damaged vacuum lines to each AIR shutoff valve. If any problems are found, repair as necessary. After repairs, go to step 8. If no problems are found, go to step 7.
6. Repair cause of low vacuum to AIR solenoid. After repairs, go to step 8.
7. Replace AIR solenoid. After replacing solenoid, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Scheme 5

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0102, P0410, P0418, P0419 (dual AIR pump system) and P0443 are set, go to next step. If DTC P0102, P0410, P0418, P0419 and P0443 are not set, go to step 4.
3. Check for short to ground in ignition feed circuit to Secondary Air Injection (AIR) pump relay. See WIRING DIAGRAMS article. see scheme 12 Repair as necessary and replace fuse. If wiring is okay, check for a shorted component that shares ignition feed fuse. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. After repairs, go to step 16.
4. Turn ignition on. Using scan tool, command AIR solenoid on and off. If AIR solenoid turns on and off with each command, go to next step. If AIR solenoid does not turn on and off with each command, go to step 6. NOTE: AIR solenoid may also be referred to as AIR by-pass valve solenoid or AIR vacuum control solenoid valve.
5. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
6. Turn ignition off. Disconnect AIR solenoid connector. (Scheme 5) Turn ignition on. Using a test light connected to ground, probe terminal No. 1 (Pink wire on models with single AIR pump or Pink/Black wire on models with dual AIR pumps) at AIR solenoid harness connector. (Scheme 6) If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
7. Connect a test light between terminals No. 1 and 2 at AIR solenoid harness connector. Using scan tool, command AIR solenoid on and off. If test light turns on and off with each command, go to step 11. If test light does not turn on and off with each command, go to next step.
8. If test light remains illuminated with each command, go to step 10. If test light does not remain illuminated with each command, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in Pink/Black wire between terminal No. 2 at AIR solenoid harness connector and terminal No. 66 at PCM C1 harness connector. see scheme 2and (Scheme 6). If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 66 (Pink/Black wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, repair short to ground in Pink/Black wire between PCM and AIR solenoid. After repairs, go to step 16. If test light does not illuminate, go to step 15.
11. Check for poor connections at AIR solenoid connector. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to step 14.
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 16. If connectors are okay. go to step 15.
13. Repair Pink wire (single AIR pump) or Pink/Black wire (dual AIR pumps) between AIR solenoid and fuse No. 11 (IGN 1 fuse) in underhood fuse block. After repairs, go to step 16.
14. Replace AIR solenoid. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Scheme 6

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0102, P0410, P0412 and P0443 are set, go to next step. If DTC P0102, P0410, P0412 and P0443 are not set, go to step 4.
3. Check for short to ground in ignition feed circuit to Secondary Air Injection (AIR) pump relay. See WIRING DIAGRAMS article. see scheme 12 Repair as necessary and replace fuse. If wiring is okay, check for a shorted component that shares ignition feed fuse. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. After repairs, go to step 16.
4. Turn ignition on. Using scan tool, command AIR pump relay on and off. If AIR pump relay turns on and off with each command, go to next step. If AIR pump relay does not turn on and off with each command, go to step 6.
5. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
6. Turn ignition off. Disconnect AIR pump relay. see scheme 12 Turn ignition on. Using a test light connected to ground, probe terminal No. 85 (Pink wire) at AIR pump relay harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
7. Connect a test light between terminals No. 85 (Pink wire) and No. 86 (Brown wire) at AIR pump relay harness connector. Using scan tool, command AIR pump relay on and off. If test light turns on and off with each command, go to step 11. If test light does not turn on and off with each command, go to next step.
8. If test light remains illuminated with each command, go to step 10. If test light does not remain illuminated with each command, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in Brown wire between terminal No. 86 at AIR pump relay harness connector and terminal No. 75 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 75 (Brown wire) at PCM C1 harness connector. If test light illuminates, repair short to ground in Brown wire between PCM and AIR pump relay. After repairs, go to step 16. If test light does not illuminate, go to step 15.
11. Check for poor connections at AIR pump relay connector. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to step 14.
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 16. If connectors are okay, go to step 15.
13. Repair Pink wire between AIR pump relay and fuse No. 11 (IGN 1 fuse) in underhood fuse block. After repairs, go to step 16.
14. Replace AIR pump relay. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Vehicle is equipped with 2 AIR relays, pump relay 1 and pump relay 2. AIR pump relay 1 may also be referred to as AIR pump relay "A". AIR pump relay 2 may also be referred to as AIR pump relay "B".

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0102, P0410, P0412, P0419 and P0443 are set, go to next step. If DTC P0102, P0410, P0412, P0419 and P0443 are not set, go to step 4.
3. Check for short to ground in ignition feed circuit to Secondary Air Injection (AIR) pump relay 1. See WIRING DIAGRAMS article. see scheme 12 Repair as necessary and replace fuse. If wiring is okay, check for a shorted component that shares ignition feed fuse. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. After repairs, go to step 16.
4. Turn ignition on. Using scan tool, command AIR pump relay 1 on and off. If AIR pump relay 1 turns on and off with each command, go to next step. If AIR pump relay 1 does not turn on and off with each command, go to step 6.
5. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
6. Turn ignition off. Disconnect AIR pump relay 1. see scheme 12 Turn ignition on. Using a test light connected to ground, probe terminal No. 85 (Pink/Black wire) at AIR pump relay 1 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
7. Connect a test light between terminals No. 85 (Pink/Black wire) and No. 86 (Brown/White wire) at AIR pump relay 1 harness connector. Using scan tool, command AIR pump relay 1 on and off. If test light turns on and off with each command, go to step 11. If test light does not turn on and off with each command, go to next step.
8. If test light remains illuminated with each command, go to step 10. If test light does not remain illuminated with each command, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in Brown/White wire between terminal No. 86 at AIR pump relay 1 harness connector and terminal No. 54 at PCM C2 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 54 (Brown/White wire) at PCM C2 harness connector. If test light illuminates, repair short to ground in Brown/White wire between PCM and AIR pump replay 1. After repairs, go to step 16. If test light does not illuminate, go to step 15.
11. Check for poor connections at AIR pump relay 1 connector. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to step 14.
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 16. If connectors are okay. go to step 15.
13. Repair Pink/Black wire between AIR pump relay 1 and fuse No. 11 (IGN 1 fuse) in underhood fuse block. After repairs, go to step 16.
14. Replace AIR pump relay 1. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. Vehicle is equipped with 2 AIR relays, pump relay 1 and pump relay 2. AIR pump relay 1 may also be referred to as AIR pump relay "A". AIR pump relay 2 may also be referred to as AIR pump relay "B".

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0102, P0410, P0412 and P0443 are set, go to next step. If DTC P0102, P0410, P0412, P0419 and P0443 are not set, go to step 4.
3. Check for short to ground in ignition feed circuit to Secondary Air Injection (AIR) pump relay 2. See WIRING DIAGRAMS article. see scheme 12 Repair as necessary and replace fuse. If wiring is okay, check for a shorted component that shares ignition feed fuse. See POWER DISTRIBUTION article in WIRING DIAGRAMS. Repair as necessary. After repairs, go to step 16. NOTE: Vehicle is equipped with 2 AIR relays, pump relay 1 and pump relay 2. AIR pump relay 1 may also be referred to as AIR pump relay "A". AIR pump relay 2 may also be referred to as AIR pump relay "B".
4. Turn ignition on. Using scan tool, command AIR pump relay 2 on and off. If AIR pump relay 2 turns on and off with each command, go to next step. If AIR pump relay 2 does not turn on and off with each command, go to step 6.
5. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
6. Turn ignition off. Disconnect AIR pump relay 2. see scheme 12 Turn ignition on. Using a test light connected to ground, probe terminal No. 85 (Pink/Black wire) at AIR pump relay 2 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 13.
7. Connect a test light between terminals No. 85 (Pink/Black wire) and No. 86 (Brown wire) at AIR pump relay 2 harness connector. Using scan tool, command AIR pump relay 2 on and off. If test light turns on and off with each command, go to step 11. If test light does not turn on and off with each command, go to next step.
8. If test light remains illuminated with each command, go to step 10. If test light does not remain illuminated with each command, go to next step.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in Brown wire between terminal No. 86 at AIR pump relay 2 harness connector and terminal No. 75 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 75 (Brown wire) at PCM C1 harness connector. If test light illuminates, repair short to ground in Brown wire between PCM and AIR pump relay 2. After repairs, go to step 16. If test light does not illuminate, go to step 15.
11. Check for poor connections at AIR pump relay 2 connector. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to step 14.
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 16. If connectors are okay. go to step 15.
13. Repair Pink/Black wire between AIR pump relay 2 and fuse No. 11 (IGN 1 fuse) in underhood fuse block. After repairs, go to step 16.
14. Replace AIR pump relay 2. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If any other DTCs are set, diagnose DTCs before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If no other DTCs are set, go to next step.
3. Check exhaust system for leaks, damage, and loose or missing hardware. Repair exhaust system as necessary. After repairs, go to step 6 . If exhaust system is okay, go to next step.
4. Ensure original 3-way catalytic converter is installed correctly. Check catalytic converter for damage, severe discoloration or tampering. Ensure oxygen sensors are properly installed and wiring and connections are okay. If any problems are found, repair as necessary. After repairs, go to step 6 . If no problems are found, go to next step.
5. Replace catalytic converter. After repairs, go to next step.
6. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

Fuel with high sulfur content can cause a marginal converter to look bad. Check fuel quality.

Note. EVAP Pressure/Purge Diagnostic Station (J 41413) is required to pressurize EVAP system in the following test.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0443 or DTC P0449 is also set, see «DTC P0443: EVAPORATIVE EMISSION PURGE VALVE 1 CONTROL CIRCUIT»(ref-121492-S13587218142001100100000) or «DTC P0449: EVAPORATIVE EMISSION VENT VALVE CONTROL CIRCUIT»(ref-121492-S22233118982001100100000). If DTC P0443 or DTC P0449 is not set, go to next step.
3. Inspect EVAP system for the following conditions. Check for loose, missing or damaged service port Schrader valve. Check for loose, incorrect, missing or damaged fuel filler cap. Check for damaged EVAP canister purge valve. (Scheme 7) Raise and support vehicle. Check for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses. Check for damaged EVAP canister vent valve. EVAP canister vent valve is located near fuel tank. (Scheme 8) Check for damaged EVAP canister. EVAP canister is located near fuel tank. (Scheme 9) If any problems are found, repair as necessary. After repairs, go to 17. If no problems are found, go to next step.
4. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gauge for one minute. If pressure stays at 5 in. H2O, go to next step. If pressure does not stay at 5 in. H2O, go to step 7.
5. Using scan tool, observe Fuel Tank Pressure (FTP) sensor value. Compare EVAP pressure/purge diagnostic station value to scan tool FTP sensor value. If EVAP pressure/purge diagnostic station value is near scan tool value, go to next step. If EVAP pressure/purge diagnostic station value is not near scan tool value, go to step 11.
6. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect EVAP purge pipe from EVAP canister purge valve. (Scheme 7) If EVAP system pressure decreases, go to step 8. If EVAP system pressure does not decrease, go to step 9.
7. Using EVAP pressure/purge diagnostic station, continuously pressurize EVAP system. Using Ultrasonic Leak Detector (J 41416) check EVAP system for leaks. Carefully leak test all EVAP system hoses, tubes and connections. It may be necessary to partially lower fuel tank to inspect components located in upper portion of fuel tank. If any leaks are found, repair as necessary. After repairs, go to step 17. If no leaks are found, see «DIAGNOSTIC AIDS»(ref-121492-S22200814052001082900000).
8. Connect a vacuum gauge to EVAP purge valve purge pipe port. Start engine and allow it to idle. Using scan tool, command EVAP canister purge valve to 50 percent. If vacuum gauge indicates an increase in vacuum, see «DIAGNOSTIC AIDS»(ref-121492-S22200814052001082900000). If vacuum gauge does not indicate an increase in vacuum, go to step 14.
9. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect purge pipe from EVAP canister. (Scheme 9) If EVAP system pressure decreases, go to step 15. If EVAP system pressure does not decrease, go to next step.
10. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Disconnect vapor pipe from EVAP canister. If EVAP system pressure decreases, go to step 16. If EVAP system pressure does not decrease, go to step 13.
11. Using scan tool, monitor FTP sensor voltage. If voltage is more than 4.3 volts, go to «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE»(ref-121492-S23110401702001092800000). If voltage is 4.3 volts or less, go to next step.
12. Replace FTP sensor. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. After repairs, go to step 17.
13. Repair pinched or obstructed EVAP vapor pipe. After repairs, go to step 17.
14. Replace EVAP canister purge valve. After repairs, go to step 17.
15. Repair restriction in EVAP purge pipe. After repairs, go to step 17.
16. Replace EVAP canister. After repairs, go to next step.
17. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gauge for 5 minutes. If pressure stays at 5 in. H2O, go to next step. If pressure does not stay at 5 in. H2O, go to step 7.
18. Monitor pressure gauge on EVAP pressure/purge diagnostic station. Using scan tool, command EVAP purge valve to 50 percent. If EVAP system pressure decreases, go to next step. If EVAP system pressure does not decrease, go to step 9.
19. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Use EVAP Pressure/Purge Diagnostic Station (J 41413) to pressurize EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with Ultrasonic Leak Detector (J 41416). A temporary blockage in EVAP canister purge valve, purge pipe or EVAP canister could cause an intermittent condition. Reviewing FAILURE RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to set occurs. This may assist in diagnosing condition.

Scheme 7

Scheme 8

Scheme 9

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0443 or DTC P0449 is also set, see «DTC P0443: EVAPORATIVE EMISSION PURGE VALVE 1 CONTROL CIRCUIT»(ref-121492-S13587218142001100100000) or «DTC P0449: EVAPORATIVE EMISSION VENT VALVE CONTROL CIRCUIT»(ref-121492-S22233118982001100100000). If DTC P0443 or DTC P0449 is not set, go to next step.
3. Inspect EVAP system for the following conditions. Check for loose, missing or damaged service port Schrader valve. Check for loose, incorrect, missing or damaged fuel filler cap. Check for damaged EVAP canister purge valve. (Scheme 7) Raise and support vehicle. Check for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses. Check for damaged EVAP canister vent valve. EVAP canister vent valve is located near fuel tank. (Scheme 8) Check for damaged EVAP canister. EVAP canister is located near fuel tank. (Scheme 9) If any problems are found, repair as necessary. After repairs, go to 6. If no problems are found, go to next step.
4. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gauge for one minute. If pressure stays at 5 in. H2O, go to «DIAGNOSTIC AIDS»(ref-121492-S04176463422001092800000). If pressure does not stay at 5 in. H2O, go to next step.
5. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, continuously pressurize system to 15 in. H2O. Using Ultrasonic Leak Detector (J 41416) check EVAP system for leaks. Carefully leak test all EVAP system hoses, tubes and connections. It may be necessary to partially lower fuel tank to inspect components located in upper portion of fuel tank. If any leaks are found, repair as necessary. After repairs, go to next step. If no problems are found, see «DIAGNOSTIC AIDS»(ref-121492-S04176463422001092800000).
6. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, seal EVAP system. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Monitor pressure gauge for one minute. If pressure stays at 5 in. H2O, go to next step. If pressure does not stay at 5 in. H2O, go to step 2.
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

EVAP system tests run when engine is first started and meets code enable criteria for this DTC. Use EVAP Pressure/Purge Diagnostic Station (J 41413) to pressurize EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with Ultrasonic Leak Detector (J 41416).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, command EVAP canister purge valve to 50 percent, and then to zero percent. If a clicking noise is felt or heard from EVAP canister purge valve when commanded to 50 percent, go to next step. (Scheme 7) If a clicking noise is not felt or heard from EVAP canister purge valve when commanded to 50 percent, go to step 4.
3. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect EVAP purge valve connector. Turn ignition on. Using a test light connected to ground, probe Pink wire at EVAP purge valve harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
5. Connect a test light between Pink and Dark Green/White wires at EVAP purge valve harness connector. Using scan tool, command EVAP canister purge valve to zero percent. If test light illuminates, go to step 9. If test light does not illuminate, go to next step.
6. Using scan tool, command EVAP canister purge valve to 50 percent. If test light illuminates or pulses, go to step 8. If test light does not illuminate or pulse, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in Dark Green/White wire between EVAP canister purge valve harness connector and terminal No. 42 at PCM C2 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 14. If no problems are found, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Using a test light connected to positive battery voltage, probe Dark Green/White wire at EVAP canister purge valve harness connector. If test light illuminates, repair short to ground in Dark Green/White wire between EVAP canister purge valve and PCM. After repairs, go to step 14. If test light does not illuminate, go to step 13.
9. Check for poor connections at EVAP purge valve connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 12.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
11. Repair open or short to ground in power circuit (Pink wire) to EVAP canister purge valve. Also check fuse No. 11 (IGN 1 fuse) in underhood fuse block. After repairs, go to step 14.
12. Replace EVAP canister purge valve. After repairs, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Note. EVAP Pressure/Purge Diagnostic Station (J 41413) is required to pressurize EVAP system in the following test.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0443, P0449, P0452 or P0543 is also set, repair DTC(s) before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If DTC P0443, P0449, P0452 or P0543 is not set, go to next step.
3. Check for damaged EVAP canister vent valve or pinched EVAP canister vent valve hose. EVAP canister vent valve is located near fuel tank. (Scheme 8) If any problems are found, repair as necessary. After repairs, go to 14. If no problems are found, go to next step.
4. Disconnect purge line from EVAP canister purge valve. (Scheme 7) Ensure ignition is on. Using scan tool, observe fuel tank pressure parameter. If scan tool indicates fuel tank pressure is about zero in. H2O, go to next step. If scan tool does not indicate fuel tank pressure is about zero in. H2O, go to step 8.
5. Turn ignition off. Reconnect all connectors and components. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, command EVAP vent valve ON. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Using scan tool, command EVAP vent valve OFF. If fuel tank pressure changes to zero in. H2O, no problem is indicated. Fault may be intermittent. See «DIAGNOSTIC AIDS»(ref-121492-S10675595532001100100000). If fuel tank pressure does not change to zero in. H2O, go to step 7.
6. While observing scan tool, disconnect vent hose from EVAP canister vent valve. (Scheme 8) If fuel tank pressure changes to zero in. H2O, go to step 10. If fuel tank pressure does not change to zero in. H2O, go to next step.
7. Disconnect vent hose/pipe from EVAP canister. (Scheme 9) If fuel tank pressure changes to zero in. H2O, go to step 13. If fuel tank pressure does not change to zero in. H2O, go to step 11.
8. Using scan tool, monitor FTP sensor voltage. If voltage is more than 4.3 volts, go to «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE»(ref-121492-S23110401702001092800000). If voltage is 4.3 volts or less, go to next step.
9. Check for poor connections at FTP sensor connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 12.
10. Replace EVAP canister vent valve. After repairs, go to step 14.
11. Replace EVAP canister. After repairs, go to step 14.
12. Replace FTP sensor. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. After repairs, go to step 14.
13. Repair pinched or obstructed EVAP vent hose/pipe. After repairs, go to next step.
14. Turn ignition off. Reconnect all connectors and components. Remove fuel filler cap. Install Fuel Tank Cap Adapter (J 41415-40). Connect EVAP Pressure/Purge Station (J 41413). Install vehicle fuel filler cap to fuel fill cap adaptor. Zero pressure and vacuum gauges on EVAP pressure/purge station. Turn ignition on. Using scan tool, command EVAP vent valve ON. Using EVAP pressure/purge diagnostic station, pressurize system to 5 in. H2O. Rotate EVAP pressure/purge diagnostic station rotary switch to OFF/HOLD position. Using scan tool, command EVAP vent valve OFF. If fuel tank pressure changes to zero in. H2O, go to next step. If fuel tank pressure does not change to zero in. H2O, go to step 3.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP vent valve inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine and allow it to idle. Using scan tool, command EVAP vent valve ON and OFF. If a clicking noise is felt or heard from EVAP vent valve, go to next step. EVAP canister vent valve is located near fuel tank. (Scheme 8) If a clicking noise is not felt or heard from EVAP vent valve, go to step 4.
3. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect EVAP vent valve connector. Turn ignition on. Using a test light connected to ground, probe Pink wire at EVAP vent valve harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
5. Connect a test light between Pink and White wires at EVAP vent valve harness connector. Using scan tool, command EVAP vent valve ON and OFF. If test light turns on and off with each command, go to step 9. If test light does not turn on and off with each command, go to next step.
6. If test light remains on with each command, go to step 8. If test light does not remain on with each command, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to voltage in White wire between EVAP canister vent valve harness connector and terminal No. 73 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 14. If no problems are found, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Using a test light connected to positive battery voltage, probe White wire at EVAP canister vent valve harness connector. If test light illuminates, repair short to ground in White wire between EVAP canister vent valve and PCM. After repairs, go to step 14. If test light does not illuminate, go to step 10.
9. Check for poor connections at EVAP vent valve connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 12.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
11. Repair open or short to ground in power circuit (Pink wire) to EVAP canister vent valve. Also check fuse No. 11 (VENT SOL fuse) in rear fuse block. Rear fuse block is located underneath driver's side rear seat. After repairs, go to step 14.
12. Replace EVAP canister vent valve. After repairs, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P1639 is also set, go to «DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT»(ref-121492-S28291029472001082900000). If DTC P1639 is not set, go to next step.
3. Ensure ignition is on. Using scan tool, observe FTP sensor voltage. If voltage is less than.1 volt, go to step 5. If voltage is.1 volt or more, go to next step.
4. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Disconnect FTP sensor. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. Turn ignition on. Connect a jumper wire between terminal "B" (Dark Green wire) and terminal "C" (Gray wire) at FTP sensor harness connector. (Scheme 10) Using scan tool, observe FTP sensor voltage. If voltage is about 5 volts, go to step 9. If voltage is not about 5 volts, go to next step.
6. Remove jumper wire. Connect a DVOM between terminal "A" (White wire) and terminal "C" (Gray wire) at FTP sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 8.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM and FTP sensor connectors. Repair connectors as necessary. If connectors are okay, check FTP sensor signal circuit (Dark Green wire) as follows: Check continuity of Dark Green wire between terminal "B" at FTP sensor harness connector and terminal No. 5 at PCM C1 harness connector. see scheme 2and (Scheme 10). Continuity should exist. If continuity does not exist, Dark Green wire is open. Check for continuity between terminal "A" (White wire) and terminal "B" (Dark Green wire) at FTP sensor harness connector. Continuity should not exist. If continuity exists, White and Dark Green wires are shorted together. Using a test light connected to positive battery voltage, probe terminal "B" (Dark Green wire) at FTP sensor harness connector. Test light should not illuminate. If test light illuminates, Dark Green wire is shorted to ground. If any problems are found, repair as necessary. After repairs, go to step 12. If no problems are found, go to step 11.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM and FTP sensor connectors. Repair connectors as necessary. If connectors are okay, check continuity of Gray wire between terminal "C" at FTP sensor harness connector and terminal No. 17 at PCM C2 harness connector. see scheme 2and (Scheme 10). If continuity does not exist, repair open in Gray wire. After repairs, go to step 12. If continuity exists, go to step 11.
9. Check for poor connections at FTP sensor connector. Repair connector as necessary. After repairs, go to step 12. If connector is okay, go to next step.
10. Replace FTP sensor. After repairs, go to step 12.
11. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
12. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Scheme 10

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Idle engine for one minute. Using scan tool, monitor DTC information. If DTC P1635 or P1639 sets, go to P1639. If DTC P1635 or P1639 is not set, go to next step.
3. Turn ignition on. Using scan tool, observe FTP sensor voltage. If voltage is more than 4.3 volts, go to step 5. If voltage is 4.3 volts or less, go to next step.
4. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Disconnect FTP sensor. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. Turn ignition on. Using scan tool, observe FTP sensor voltage. If voltage is more than zero, go to next step. If voltage is about zero volts, go to step 7.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for poor connections at PCM connectors. Repair connectors as necessary. If connectors are okay, check FTP sensor signal circuit (Dark Green wire) as follows: Check for continuity between terminal "B" (Dark Green wire) and terminal "C" (Gray wire) at FTP sensor harness connector. (Scheme 10) Continuity should not exist. If continuity exists, Dark Green and Gray wires are shorted together. Using a test light connected to ground, probe terminal "B" (Dark Green wire) at FTP sensor harness connector. Test light should not illuminate. If test light illuminates, Dark Green wire is shorted to voltage. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to step 12.
7. Using a test light connected to positive battery voltage, probe terminal "A" (White wire) at FTP sensor harness connector. If test light illuminates, go to step 9. If test light does not illuminate, go to next step.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity between terminal "A" (White wire) at FTP sensor harness connector and terminal No. 13 (Black/White wire) at PCM C2 harness connector. see scheme 2and (Scheme 10). If continuity does not exist, repair open in White or Black/White wire. See WIRING DIAGRAMS article. After repairs, go to step 13. If continuity exists, go to step 10.
9. Check for poor connections at FTP sensor connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to step 11.
10. Check for poor connections at PCM connectors. Repair connector as necessary. After repairs, go to step 13. If connectors are okay, go to step 12.
11. Replace FTP sensor. After repairs, go to step 13.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If engine cooling diagnostic system check has already been performed, go to next step. If engine cooling diagnostic system check has not been perform, go to «ENGINE COOLING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08170905392001100500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, command low speed fans on and off. If cooling fan 1 relay turns on and off with each command, see «DIAGNOSTIC AIDS»(ref-121492-S27123152672001100800000). Cooling fan 1 relay is located in underhood fuse block. If cooling fan 1 relay does not turn on and off with each command, go to next step.
3. Turn ignition off. Remove cooling fan 1 relay. Turn ignition on. Using a test light connected to ground, probe battery voltage circuit at cooling fan 1 relay connector in underhood fuse block. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
4. Connect test light between cooling fan 1 relay control circuit (Dark Green wire) and battery voltage circuit at cooling fan 1 relay connector in underhood fuse block. Using scan tool, command low speed fans on and off. If test light turns on and off with each command, go to step 10. If test light does not turn on and off with each command, go to next step.
5. If test light remains illuminated with each command, go to step 7. If test light does not remain illuminated with each command, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check control circuit (Dark Green wire) for cooling fan 1 relay as follows: Check continuity of Dark Green wire between cooling fan 1 relay connector in underhood fuse block and terminal No. 25 at PCM C1 harness connector. see scheme 2 Continuity should exist. If continuity does not exist, Dark Green wire is open. Turn ignition on. Measure voltage between ground and terminal No. 25 (Dark Green wire) at PCM C1 harness connector. If any voltage is indicated, Dark Green wire is shorted to voltage between PCM and cooling fan 1 relay connector in underhood fuse block. If any problems are found, repair wiring as necessary. After repairs, go to step 14. If no problems are found, go to step 9.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 25 (Dark Green wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, repair short to ground in Dark Green wire between PCM and cooling fan 1 relay connector in underhood fuse block. After repairs, go to step 14. If test light does not illuminate, go to step 9.
8. Turn ignition off. Check for an open or short to ground in cooling fan relay 1 battery voltage circuit between fuse No. 47 and cooling fan relay 1 connector at underhood fuse block. If any problems are found, repair as necessary. After repairs, go to step 14. If no problems are found, go to step 11.
9. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 14. If connectors are okay, go to step 13.
10. Turn ignition off. Check for poor connections at cooling fan 1 relay connector in underhood fuse block. Repair connector as necessary. After repairs, go to step 14. If connectors are okay, go to step 12.
11. Repair short to ground in cooling fan motor supply voltage circuit (Gray wire). After repairs, go to step 14.
12. Replace cooling fan 1 relay. After replacing relay, go to step 14.
13. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Intermittent can be caused by poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check connectors for backed-out terminals, improper mating, broken lock, damaged terminal or poor terminal to wire connection. Review FREEZE/FAILURE RECORDS vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

1. If engine cooling diagnostic system check has already been performed, go to next step. If engine cooling diagnostic system check has not been perform, go to «ENGINE COOLING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08170905392001100500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, command high speed fans on and off. If cooling fan S/P relay and cooling fan 2 relay turn on and off with each command, see «DIAGNOSTIC AIDS»(ref-121492-S40886670212001102300000). Cooling fan S/P relay and cooling fan 1 relay are located in underhood fuse block. If cooling fan S/P relay and cooling fan 1 relay do not turn on and off with each command, go to next step.
3. Turn ignition off. Remove cooling fan 2 relay. Turn ignition on. Using a test light connected to ground, probe battery voltage circuit at cooling fan 2 relay connector in underhood fuse block. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
4. Connect test light between cooling fan 2 relay control circuit (Dark Blue wire) and battery voltage circuit at cooling fan 2 relay connector in underhood fuse block. Using scan tool, command high speed fans on and off. If test light turns on and off with each command, go to step 9. If test light does not turn on and off with each command, go to next step.
5. If test light remains illuminated with each command, go to step 7. If test light does not remain illuminated with each command, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check control circuit (Dark Blue wire) for cooling fan 2 relay as follows: Check continuity of Dark Blue wire between cooling fan 2 relay connector in underhood fuse block and terminal No. 55 at PCM C2 harness connector. see scheme 2 Also check continuity of Dark Blue wire between cooling fan S/P relay connector in underhood fuse block and terminal No. 55 at PCM C2 harness connector. Both readings should indicate continuity exists. If continuity does not exist, Dark Blue wire is open. Turn ignition on. Measure voltage between ground and terminal No. 55 (Dark Blue wire) at PCM C2 harness connector. If any voltage is indicated, Dark Blue wire is shorted to voltage between PCM and cooling fan 2 relay or cooling fan S/P relay connector in underhood fuse block. If any problems are found, repair wiring as necessary. After repairs, go to step 12. If no problems are found, go to step 9.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal No. 55 (Dark Blue wire) at PCM C2 harness connector. see scheme 2 If test light illuminates, repair short to ground in Dark Blue wire between PCM and cooling fan 2 relay connector or cooling fan S/P relay in underhood fuse block. After repairs, go to step 12. If test light does not illuminate, go to step 9.
8. Turn ignition off. Check for an open or short to ground in battery voltage circuit for cooling fan S/P relay and cooling fan relay 2 in underhood fuse block. If any problems are found, repair as necessary. After repairs, go to step 12. If no problems are found, go to step 10.
9. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 12. If connectors are okay, go to step 11.
10. Repair short to ground in cooling fan motor supply voltage circuit (Light Blue wire). After repairs, go to step 12.
11. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
12. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Intermittent can be caused by poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check connectors for backed-out terminals, improper mating, broken lock, damaged terminal or poor terminal to wire connection. Review FREEZE/FAILURE RECORDS vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Set parking brake and block drive wheels. Start engine. Turn all accessories off. Using scan tool RPM control function, slowly increment engine speed to 1700 RPM, then to 600 RPM, then back to 1700 RPM. Exit RPM control function. If engine speed stabilizes within 100 RPM of commanded RPM, go to next step. If engine speed does not stabilize within 100 RPM of commanded RPM, go step 4.
3. Using scan tool, observe FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME and/or FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S29552564122001100100000).
4. Turn ignition off. Disconnect IAC valve connector. Connect IAC Motor Driver (J 37027-A) to IAC valve. Start engine. Using IAC motor driver, command IAC valve in until about 600 RPM is reached, then command IAC valve out until about 1700 RPM is reached. Return engine speed to desired idle as indicated on scan tool data list. If engine speed steadily decreased to about 600 RPM, and then steadily increased to about 1700 RPM when IAC valve was commanded, go to next step. If engine speed did not steadily decrease to about 600 RPM, and then steadily increase to about 1700 RPM when IAC valve was commanded, go to step 11.
5. Using a test light connected to ground, probe any IAC valve circuit at IAC valve harness connector using Connector Test Adapter Kit (J 36616). Start engine. Using IAC motor driver, command low RPM while observing scan tool until IAC counts start to increment, then command high RPM while observing a scan tool until IAC counts start to increment. Observe test light while IAC counts are incrementing. Return engine idle speed to desired idle as indicated on scan tool data list. Repeat procedure for remaining 3 IAC valve circuits. If test light remained on, (never flashed) while IAC counts were incrementing at any IAC valve circuit, go to step 10. If test light did not remain on, (never flashing) while IAC counts were incrementing at any IAC valve circuit, go to next step.
6. If test light remained off (never flashed), go to step 9. If test light did not remain off, go to next step.
7. Using connector test kit adapter, connect a test light between terminal "C" (Light Blue/Black wire) and terminal "D" (Light Blue/White wire) at IAC valve harness connector. (Scheme 11) Using IAC motor driver, command low RPM while observing scan tool until IAC counts start to increment, then command high RPM while observing scan tool until IAC counts start to increment. Observe test light while IAC counts are incrementing. Return engine idle speed to desired idle as indicated on scan tool data list. Repeat procedure with test light connected between terminal "A" (Light Green/Black wire) and terminal "B" (Light Green/White wire) at IAC valve harness connector. Return engine speed to desired idle as indicated on scan tool data list. If test light remained on (never flashing) while IAC counts where incrementing during test, go to next step. If test light did not remain on (never flashing) while IAC counts where incrementing during test, go to step 15.
8. Check for poor connections at IAC valve connector. Repair connector as necessary. After repairs, go to step 16. If connectors are okay, see «DIAGNOSTIC AIDS»(ref-121492-S29552564122001100100000).
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a DVOM, check for an open or short ground on IAC valve circuit where test light remained off. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
10. Turn ignition on. Using a DVOM, check for short to voltage on IAC valve circuit where test light remained illuminated. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 12.
11. Visually and physically inspect for the following: Throttle body damage and tampering. Throttle lever screw tampering, if equipped. Restricted air intake system. Inspect for a possible collapsed or clogged air intake duct before and after air filter element, restricted air filter element, or restriction at throttle body intake screen, if equipped. Remove IAC valve. Inspect for the following: A clogged IAC passage. Excessive deposits on throttle plate. Excessive deposits in throttle bore. Excessive deposits on IAC valve pintle. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 13.
12. Check for poor connections at PCM connectors. Repair connector as necessary. After repairs, go to step 16. If connectors are okay, go to step 15.
13. Check for poor connections at IAC valve connector. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to next step.
14. Replace IAC valve. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Inspect for the following conditions

1. Check for restricted air intake system.
2. Check for collapsed, clogged, or loose air intake ducts, clogged air filter, and proper operation of mass airflow sensor.
3. Check for a tampered or damaged throttle stop screw.
4. Check for a tampered or damaged throttle plate, throttle shaft, or throttle linkage.
5. Check for objects blocking IAC passage or throttle bore.
6. Check for excessive deposits in IAC passage or on IAC pintle. Check for excessive deposits in throttle bore or on throttle plate.
7. Check for vacuum leaks.
8. A low or unstable idle condition could be caused by a non-IAC system problem that cannot be overcome by IAC valve. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.

Scheme 11

1. If air conditioning diagnostic system check has already been performed, go to next step. If air conditioning diagnostic system check has not been performed, go to «AIR CONDITIONING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S29233993442001101300000) under DIAGNOSTIC SYSTEM CHECKS. NOTE: Ambient air temperature must be more than 38°F (3°C) to ensure accurate test results.
2. Turn ignition off. Verify A/C compressor has free rotation. Start engine. Turn A/C system off. If A/C compressor clutch is engaged, diagnose A/C compressor clutch. See COMPRESSOR CLUTCH DOES NOT DISENGAGE under SYMPTOM TESTS in AUTOMATIC A/C-HEATER SYSTEMS - AURORA article in AIR CONDITIONING & HEATING. If A/C clutch is not engaged, turn ignition off and go to next step.
3. Turn ignition on. Using scan tool, select PCM data list and observe A/C high-side pressure voltage parameter. If voltage is 0.1-4.9 volts, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(ref-121492-S03541028272001101300000). If voltage is not 0.1-4.9 volts, go to next step.
4. Turn ignition off. Disconnect A/C pressure sensor. Sensor is located in discharge hose of A/C compressor Turn ignition on. Using scan tool, observe A/C high-side pressure voltage parameter. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, go to step 11.
5. Turn ignition off. Connect a 3-amp fused jumper wire between terminals "B" (Gray wire) and "C" (Red/Black wire) at A/C pressure sensor harness connector. Turn ignition on. Using scan tool, observe A/C high-side pressure voltage parameter. If voltage is more than 4.9 volts, go to next step. If voltage is 4.9 volts or less, go to step 9.
6. Disconnect jumper wire. Measure voltage between terminals "A" (Black wire) and "B" (Gray wire) at A/C pressure sensor harness connector. If voltage is less than 5 volts, go to next step. If voltage is 5 volts or more, go to step 8.
7. Turn ignition off. Disconnect negative battery cable. Measure resistance between ground and terminal "A" (Black wire) of A/C pressure sensor harness connector. If resistance is less than 5 ohms, go to step 13. If resistance is 5 ohms or more, go to step 12.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and terminal "B" (Gray wire) of A/C pressure sensor harness connector. If any voltage is indicated, repair short to voltage in Gray wire between A/C pressure sensor and PCM. After repairs, go to step 17. If no voltage is indicated, go to step 14.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check A/C pressure sensor 5-volt reference circuit (Gray wire) for an open or short to ground between terminal "B" at A/C pressure sensor harness connector and terminal No. 57 at PCM C2 harness connector. see scheme 2 If any problems are found, repair wiring as necessary. After repairs, go to step 17. If no problems are found, go to next step.
10. Check A/C refrigerant pressure sensor signal circuit (Red/Black wire) for an open or short to ground between terminal "C" at A/C pressure sensor harness connector and terminal No. 74 at PCM C2 harness connector. If any problems are found, repair wiring as necessary. After repairs, go to step 17. If no problems are found, go to step 14.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and terminal "C" (Red/Black wire) of A/C pressure sensor harness connector. If any voltage is indicated, repair short to voltage in Red/Black wire between A/C pressure sensor and PCM. After repairs, go to step 17. If no voltage is indicated, go to step 14.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black wire between terminal "A" at A/C pressure sensor harness connector and terminal No. 14 at PCM C2 harness connector. see scheme 2 If continuity does not exist, repair open in Black wire. After repairs, go to step 17. If continuity exists, go to step 14.
13. Check for poor connections at A/C pressure sensor connector. Repair connector as necessary. After repairs, go to step 17. If connector is okay, go to step 15.
14. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 17. If connectors are okay, go to step 16.
15. Replace A/C pressure sensor. After repairs, go to step 17.
16. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
17. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 3.
18. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Ensure PCM engine grounds are clean and tight. If DTC P0532 cannot be duplicated, reviewing FAILURE RECORDS vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.

1. If engine electrical diagnostic system check has already been performed, go to next step. If engine electrical diagnostic system check has not been performed, go to «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08828289192001110500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, observe IGNITION 1 signal voltage parameter in PCM data list. If voltage is more than 11 volts, go to step 6. If voltage is 11 volts or less, go to next step.
3. Check battery voltage and compare voltage reading with ignition 1 signal voltage parameter in PCM data list. If voltages differ by more than.5 volt, go to next step. If voltages do not differ by more than.5 volt, diagnose charging system and repair as necessary.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for high resistance in battery voltage supply circuit (Orange wire) to terminals No. 20 and 21 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to next step.
5. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 7. If connectors are okay, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If engine electrical diagnostic system check has already been performed, go to next step. If engine electrical diagnostic system check has not been performed, go to «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08828289192001110500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, observe IGNITION 1 signal voltage parameter in PCM data list. If voltage is more than 10 volts, go to step 6. If voltage is 10 volts or less, go to next step.
3. Check battery voltage and compare voltage reading with ignition 1 signal voltage parameter in PCM data list. If voltages differ by more than.5 volt, go to next step. If voltages does not differ by more than.5 volt, diagnose charging system and repair as necessary.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for high resistance in battery voltage supply circuit (Orange wire) to terminals No. 20 and 21 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 7. If no problems are found, go to next step.
5. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 7. If connectors are okay, go to next step.
6. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If engine electrical diagnostic system check has already been performed, go to next step. If engine electrical diagnostic system check has not been performed, go to «ENGINE ELECTRICAL DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08828289192001110500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, observe IGNITION 1 signal voltage parameter in PCM data list. If voltage is 16 volts or more, go to next step. If voltage is less than 16 volts, go to step 4 .
3. Check battery voltage and compare voltage reading with ignition 1 signal voltage parameter in PCM data list. If voltages differ by more than .5 volt, go to next step. If voltages do not differ by more than .5 volt, diagnose charging system and repair as necessary.
4. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to next step.
5. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
6. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) .

DTC P0601 indicates that contents of EEPROM have changed since PCM was programmed. PCM must be replaced and reprogrammed.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Reprogram PCM using correct software. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . If DTC P0602 resets, go to next step.
3. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Observe MIL on right side of instrument cluster. MIL is displayed as an engine icon. If MIL is on, go to next step. If MIL if off, go to step 5.
3. Using scan tool, command MIL OFF. If MIL is off, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If MIL is on, go to next step.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Remove Instrument Panel Cluster (IPC). See REMOVAL & INSTALLATION in appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Using a test light connected to positive battery voltage, probe terminal No. 32 (Brown/White wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, repair short to ground in Brown/White wire between PCM and instrument cluster. After repairs, go to step 13. If test light does not illuminate, go to step 11.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Using a test light connected to ground, probe terminal No. 32 (Brown/White wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, go to next step. If test light does not illuminate, go to step 7.
6. Turn ignition off. Remove Instrument Panel Cluster (IPC). See REMOVAL & INSTALLATION in appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ignition on. Using a test light connected to ground, probe terminal No. 32 (Brown/White wire) at PCM C1 harness connector. see scheme 2 If test light illuminates, repair short to voltage in Brown/White wire between PCM and instrument cluster. After repairs, go to step 13. If test light does not illuminate, go to step 10.
7. Turn ignition off. Reconnect PCM connectors. Remove Instrument Panel Cluster (IPC). See REMOVAL & INSTALLATION in appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ignition on. Using a test light connected to positive battery voltage, probe terminal No. 32 (Brown/White wire) at PCM C1 harness connector. Using scan tool, command MIL ON and OFF. If test light turns on and off, go to next step. If test light does not turn on and off, go to step 9.
8. Check for poor connections at IPC connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, go to step 12.
9. Turn ignition off. Disconnect PCM connectors. Check continuity of Brown/White wire between terminal B1 at IPC C2 harness connector and terminal No. 32 at PCM C1 harness connector. see scheme 2and see scheme 3. If continuity exists, go to next step. If continuity does not exist, repair open in Brown/White wire. After repairs, go to step 13.
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 13. If connectors are okay, go to next step.
11. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to step 13.
12. Replace IPC. After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, clear DTCs. Observe DTC information for 30 seconds. If DTCs P0030, P1031 and P1032 are set, go to «DTC P0030: HO2S HEATER CONTROL CIRCUIT VOLTAGE IS GREATER THAN PCM INTERNAL DRIVER CAPACITY»(ref-121492-S24747406752001090400000). If DTCs P0030, P1031 and P1032 are not set, go to next step.
3. Start engine. Using scan tool, observe DTC information for 5 minutes. If P1031 and P1032 are set, go to next step. If P1031 and P1032 are not set, no problems is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Disconnect HO2S bank 1 sensor 1 connector. HO2S bank 1 sensor 1 is located in right (rear) exhaust manifold. Turn ignition on. Using a test light connected to ground, probe terminal "A" (Tan wire) at HO2S bank 1 sensor 1 harness connector. (Scheme 2) Using scan tool, command HO2S heater driver 3 on and off. If test light turns on and off, go to step 9. If test light does not turn on and off, go to next step.
5. Turn ignition off. Disconnect HO2S bank 2 sensor 1 connector. HO2S bank 2 sensor 1 is located in left (front) exhaust manifold. Turn ignition on. Using a test light connected to ground, probe terminal "A" (Tan/White wire) at HO2S bank 2 sensor 1 harness connector. (Scheme 2) Using scan tool, command HO2S heater driver 3 on and off. If test light turns on and off, go to step 8. If test light does not turn on and off, go to next step.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 52 (Tan wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Tan wire between HO2S bank 1 sensor 1 and PCM. After repairs, go to step 11. If no voltage is indicated, go to next step.
7. Measure voltage between ground and terminal No. 54 (Tan/White wire) at PCM C1 harness connector. If any voltage is indicated, repair short to voltage in Tan/White wire between HO2S bank 2 sensor 1 and PCM. After repairs, go to step 11. If no voltage is indicated, go to step 10.
8. Replace HO2S bank 2 sensor 1. After repairs, go to step 11.
9. Replace HO2S bank 1 sensor 1. After repairs, go to step 11.
10. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
11. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
12. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Using scan tool, check for any other DTCs that are set. If DTC P0108 or P1635 is not set, go to next step. If DTC P0108 or P1635 is set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). NOTE: If engine idle is rough, unstable or incorrect, correct idle condition before continuing with this test. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Using scan tool, observe MAP sensor voltage. If voltage is more than 4.5 volts, go to step 5. If voltage is 4.5 volts or less, go next step.
4. Using scan tool, observe MAP sensor voltage while wiggling MAP sensor connector, PCM connectors and relate wiring harnesses. see scheme 5 PCM is located in engine compartment, inside air filter housing. If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, see «DIAGNOSTIC AIDS»(ref-121492-S01922195782001100300000).
5. Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using scan tool, observe MAP sensor voltage. If voltage is less than.5 volt, go to next step. If voltage is.5 volt or more, go to step 8.
6. Measure voltage between Gray and Orange/Black wires at MAP sensor harness connector. If voltage is 4.7-5.2 volts, go to step 11. If voltage is not 4.7-5.2 volts, go to next step.
7. If voltage was more than 5.2 volts in previous step, go to step 10. If voltage was less than 4.7 volts in previous step, go to step 9.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Light Green wire at MAP sensor harness connector. If any voltage is indicated, repair short to voltage in Light Green wire between MAP sensor and PCM. After repairs, go to step 13. If no voltage is indicated, go to step 12.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Orange/Black wire between MAP sensor harness connector and terminal No. 6 at PCM C2 harness connector. see scheme 2 If continuity does not exist, repair open in Orange/Black wire. After repairs, go to step 13. If continuity exists, go to step 12.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and Gray wire at MAP sensor harness connector. If any voltage is indicated, repair short to voltage in Gray wire between MAP sensor and PCM. After repairs, go to step 13. If no voltage is indicated, go to step 12.
11. Check for poor connections at MAP sensor connector. Repair connector as necessary. After repairs, go to step 13. If connector is okay, see «DIAGNOSTIC AIDS»(ref-121492-S01922195782001100300000).
12. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to next step. If connectors are okay, see «DIAGNOSTIC AIDS»(ref-121492-S01922195782001100300000).
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check MAP sensor vacuum source for leaks, restrictions and poor connections. If condition is still intermittent, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Using scan tool, check for any other DTCs that are set. If DTC P0107 or P1635 is not set, go to next step. If DTC P0107 or P1635 is set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). NOTE: If engine idle is rough, unstable or incorrect, correct idle condition before continuing with this test. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Using scan tool, observe MAP sensor voltage. If voltage is less than.5 volt, go to step 5. If voltage is.5 volt or more, go next step.
4. Using scan tool, observe MAP sensor voltage while wiggling MAP sensor connector, PCM connectors and relate wiring harnesses. see scheme 5 PCM is located in engine compartment, inside air filter housing. If voltage is less than.5 volt, go to next step. If voltage is.5 volt or more, see «DIAGNOSTIC AIDS»(ref-121492-S40903787352001100300000).
5. Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using scan tool, observe MAP sensor voltage. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 7.
6. Connect a 3-amp fused jumper wire between Gray and Light Green wires at MAP sensor harness connector. Using scan tool, observe MAP sensor voltage. If voltage is about 5 volts, go to step 9. If voltage is not about 5 volts, disconnect jumper wire and go to step 8.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in 5-volt reference circuit (Gray wire) between MAP sensor harness connector and terminal No. 49 at PCM C2 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 11. If no problems are found, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check for an open or short to ground in signal circuit (Light Green wire) between MAP sensor harness connector and terminal No. 23 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 11. If no problems are found, go to step 10.
9. Check for poor connections at MAP sensor connector. Repair connector as necessary. After repairs, go to step 11. If connector is okay, see «DIAGNOSTIC AIDS»(ref-121492-S40903787352001100300000).
10. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to next step. If connectors are okay, see «DIAGNOSTIC AIDS»(ref-121492-S40903787352001100300000).
11. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
12. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check MAP sensor vacuum source for leaks, restrictions and poor connections. If condition is still intermittent, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for any other DTCs that are set. If no other DTCs are set, go to next step. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
3. Ensure ignition is off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Disconnect MAF/IAT sensor connector. IAT sensor is integral to MAF sensor. Check IAT sensor signal circuit (Tan wire) as follows: While wiggling wiring harness, check continuity of Tan wire between terminal "B" at MAF/IAT sensor harness connector and terminal No. 10 at PCM C1 harness connector. see scheme 2and (Scheme 3). Continuity should exist. If continuity changes, Tan wire has an open. Turn ignition on. While wiggling wiring harness, measure voltage between ground and terminal No. 10 at PCM C1 harness connector. If any voltage is indicated, Tan wire is shorted to voltage. Check PCM and MAF/IAT sensor connectors for poor connections. If any problems are found, repair as necessary. After repairs, go to step 5. If no problems are found, go to next step.
4. Turn ignition off. While wiggling wiring harness, check continuity of Black wire between terminal "A" at MAF/IAT sensor harness connector and terminal No. 4 at PCM C2 harness connector. If continuity does not exist, repair open in Black wire. After repairs, go to next step. If continuity exists, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
6. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for any other DTCs that are set. If no other DTCs are set, go to next step. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
3. Ensure ignition is off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Disconnect MAF/IAT sensor connector. IAT sensor is integral to MAF sensor. Check IAT sensor signal circuit (Tan wire) as follows: Using a test light connected to positive battery voltage, probe terminal "B" (Tan wire) at MAF/IAT sensor harness connector while wiggling wiring harness. (Scheme 3) Test light should not illuminate. If test light illuminates, Tan wire is shorted to ground. While wiggling wiring harness, check for continuity between terminal "B" (Tan wire) and terminal "A" (Black wire) at MAF/IAT sensor harness connector. Continuity should not exist. If continuity exists, Tan and Black wires are shorted together between MAF/IAT sensor and PCM. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, no problems are indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
5. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for any other DTCs that are set. If no other DTCs are set, go to next step. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
3. Ensure ignition is off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Disconnect ECT sensor connector. see scheme 5 Check ECT sensor signal circuit (Yellow wire) as follows: Using a test light connected to positive battery voltage, probe terminal Yellow wire at ECT sensor harness connector while wiggling wiring harness. Test light should not illuminate. If test light illuminates, Yellow wire is shorted to ground. While wiggling wiring harness, check for continuity between Yellow and Black wires at ECT sensor harness connector. Continuity should not exist. If continuity exists, Yellow and Black wires are shorted together between ECT sensor and PCM. If any problems are found, repair as necessary. After repairs, go to next step. If no problems are found, no problems are indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
4. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
5. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check for any other DTCs that are set. If no other DTCs are set, go to next step. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).
3. Ensure ignition is off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Disconnect ECT sensor connector. see scheme 5 Check ECT sensor signal circuit (Yellow wire) as follows: While wiggling wiring harness, check continuity of Yellow wire between ECT sensor harness connector and terminal No. 31 at PCM C2 harness connector. see scheme 2 Continuity should exist. If continuity does not exist, Yellow wire is open. Turn ignition on. While wiggling wiring harness, measure voltage between ground and terminal No. 31 at PCM C2 harness connector. If any voltage is indicated, Yellow wire is shorted to voltage. Check PCM and ECT sensor connectors for poor connections. If any problems are found, repair as necessary. After repairs, go to step 5. If no problems are found, go to next step.
4. Turn ignition off. While wiggling wiring harness, check continuity of Black wire between ECT harness connector and terminal No. 68 at PCM C2 harness connector. If continuity does not exist, repair open in Black wire. After repairs, go to next step. If continuity exists, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
5. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
6. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition off. Disconnect TP sensor connector. see scheme 5 Connect a DVOM between ground and 5-volt reference circuit (Gray wire) at TP sensor harness connector. Turn ignition on. Lightly wiggle related engine wiring harnesses and connectors for all 5-volt reference circuits while observing voltage reading. See WIRING DIAGRAMS article. Any change in voltage indicates area where a short to voltage may exist. If voltage changes, repair wiring or connectors as necessary. After repairs, go to step 9. If voltage does not change, go to next step.
3. Connect a DVOM between ground and signal circuit (Dark Blue wire) at TP sensor harness connector. Turn ignition on. Lightly wiggle related engine wiring harnesses and connectors while observing voltage reading. Any change in voltage indicates area where a short to voltage may exist. If voltage changes, repair wiring or connectors as necessary. After repairs, go to step 9. If voltage does not change, go to next step.
4. Turn ignition off. Measure resistance between ground and low reference circuit (Black/White wire) at TP sensor harness connector. Lightly wiggle related engine wiring harnesses and connectors while observing resistance reading. Any change in resistance indicates area where an open or high resistance may exist. If resistance changes, repair wiring or connectors as necessary. After repairs, go to step 9. If resistance does not change, go to next step.
5. Check for poor connections at TP sensor connector. Repair connector as necessary. After repairs, go to step 9. If connector is okay, go to next step.
6. Check for poor connections at PCM connectors. PCM is located in engine compartment, inside air filter housing. Repair connectors as necessary. After repairs, go to step 9. If connectors are okay, go to next step.
7. Connect one end of a jumper wire to Dark Blue wire at TP sensor harness connector and other end to DVOM. Using a second jumper wire, connect one end to Gray wire at TP sensor harness connector and other end to DVOM. Set DVOM to 40K (Omega) scale. Ensure jumper wires have a good connection at TP sensor and DVOM test leads. Press MIN MAX button on DVOM. Slowly depress accelerator pedal to Wide Open Throttle (WOT) and then back to closed throttle position several times. Press MIN MAX button, and record MAX reading. Press MIN MAX button again, and record MIN reading. Disconnect jumper wire from Gray wire, and reconnect jumper wire to Black/White wire at TP sensor harness connector. Press MIN MAX button on DVOM. Slowly depress accelerator pedal to WOT and back to closed throttle position several times. Press MIN MAX button, and record MAX reading. Press MIN MAX button again, and record MIN reading. If a MAX value of OL, or a MIN value of zero ohms is recorded in either test, go to next step. If a MAX value of OL, or a MIN value of zero ohms is not recorded in either test, no problem is indicated. Diagnose by symptom. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.
8. Replace TP sensor. After repairs, go to next step.
9. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
10. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition off. Disconnect TP sensor connector. see scheme 5 Connect a DVOM between ground and 5-volt reference circuit (Gray wire) at TP sensor harness connector. Turn ignition on. Lightly wiggle related engine wiring harnesses and connectors for all 5-volt reference circuits while observing voltage reading. See WIRING DIAGRAMS article. Any change in voltage indicates area where an intermittent open, high resistance or short to ground may exist. If voltage changes, repair wiring or connectors as necessary. After repairs, go to step 8. If voltage does not change, go to next step.
3. Connect a DVOM between ground and signal circuit (Dark Blue wire) at TP sensor harness connector. Turn ignition on. Lightly wiggle related engine wiring harnesses and connectors while observing voltage reading. Any change in voltage indicates area where an intermittent open, high resistance or short to ground may exist. If voltage changes, repair wiring or connectors as necessary. After repairs, go to step 8. If voltage does not change, go to next step.
4. Check for poor connections at TP sensor connector. Repair connector as necessary. After repairs, go to step 8. If connector is okay, go to next step.
5. Check for poor connections at PCM connectors. PCM is located in engine compartment, inside air filter housing. Repair connectors as necessary. After repairs, go to step 8. If connectors are okay, go to next step.
6. Connect one end of a jumper wire to Dark Blue wire at TP sensor harness connector and other end to DVOM. Using a second jumper wire, connect one end to Gray wire at TP sensor harness connector and other end to DVOM. Set DVOM to 40K (Omega) scale. Ensure jumper wires have a good connection at TP sensor and DVOM test leads. Press MIN MAX button on DVOM. Slowly depress accelerator pedal to Wide Open Throttle (WOT) and then back to closed throttle position several times. Press MIN MAX button, and record MAX reading. Press MIN MAX button again, and record MIN reading. Disconnect jumper wire from Gray wire, and reconnect jumper wire to Black/White wire at TP sensor harness connector. Press MIN MAX button on DMM. Slowly depress accelerator pedal to WOT and back to closed throttle position several times. Press MIN MAX button, and record MAX reading. Press MIN MAX button again, and record MIN reading. If a MAX value of OL, or a MIN value of zero ohms is recorded in either test, go to next step. If a MAX value of OL, or a MIN value of zero ohms is not recorded in either test, no problem is indicated. Diagnose by symptom. See SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article.
7. Replace TP sensor. After repairs, go to next step.
8. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If sent here from another DTC diagnostic test, go to step 4 . If not sent here from another DTC diagnostic test, go to next step.
3. If any other DTCs are set, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If no other DTCs are set, go to next step.
4. Start engine. Using scan tool, observe ECT sensor parameters. View both engine speed and HO2S bank 1 sensor 1 until engine is at normal operating temperature. Increase engine speed to 2000 RPM for 2 minutes. If HO2S bank 1 sensor 1 voltage rapidly switches from less than 325 millivolts to more than 625 millivolts, go to next step. If HO2S bank 1 sensor 1 voltage does not rapidly switch from less than 325 millivolts to more than 625 millivolts, go to step 6 .
5. Increase engine speed to 2000 RPM. Using scan tool, observe LOOP STATUS. If scan tool indicates CLOSED, no problem is indicated at this time. If scan tool does not indicate CLOSED, go to step 9 .
6. If voltage in step 4 remains within 325-625 millivolts the majority of the time, go to step 9 . If voltage does not remain within 325-625 millivolts the majority of the time, go to next step.
7. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to 10 . If connectors are okay, go to next step.
8. Check for poor connections at HO2S bank 1 sensor 1 connector. Repair connector as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
9. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 1. After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If sent here from another DTC diagnostic test, go to step 4 . If not sent here from another DTC diagnostic test, go to next step.
3. If any other DTCs are set, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If no other DTCs are set, go to next step.
4. Start engine. Using scan tool, observe ECT sensor parameters. View both engine speed and HO2S bank 1 sensor 1 until engine is at normal operating temperature. Increase engine speed to 2000 RPM for 2 minutes. If HO2S bank 1 sensor 1 voltage rapidly switches from less than 325 millivolts to more than 625 millivolts, go to next step. If HO2S bank 1 sensor 1 voltage does not rapidly switch from less than 325 millivolts to more than 625 millivolts, go to step 6 .
5. Increase engine speed to 2000 RPM. Using scan tool, observe LOOP STATUS. If scan tool indicates CLOSED, no problem is indicated at this time. If scan tool does not indicate CLOSED, go to step 9 .
6. If voltage in step 4 remains within 325-625 millivolts the majority of the time, go to step 9 . If voltage does not remain within 325-625 millivolts the majority of the time, go to next step.
7. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to 10 . If connectors are okay, go to next step.
8. Check for poor connections at HO2S bank 1 sensor 1 connector. Repair connector as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
9. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 1 sensor 1. After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If sent here from another DTC diagnostic test, go to step 4 . If not sent here from another DTC diagnostic test, go to next step.
3. If any other DTCs are set, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If no other DTCs are set, go to next step.
4. Start engine. Using scan tool, observe ECT sensor parameters. View both engine speed and HO2S bank 2 sensor 1 until engine is at normal operating temperature. Increase engine speed to 2000 RPM for 2 minutes. If HO2S bank 2 sensor 1 voltage rapidly switches from less than 325 millivolts to more than 625 millivolts, go to next step. If HO2S bank 2 sensor 1 voltage does not rapidly switch from less than 325 millivolts to more than 625 millivolts, go to step 6 .
5. Increase engine speed to 2000 RPM. Using scan tool, observe LOOP STATUS. If scan tool indicates CLOSED, no problem is indicated at this time. If scan tool does not indicate CLOSED, go to step 9 .
6. If voltage in step 5 stays at 325-625 millivolts more than switching outside of 325-625 millivolts, go to step 9 . If voltage does not stay at 325-625 millivolts more than switching outside of 325-625 millivolts, go to next step.
7. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to 10 . If connectors are okay, go to next step.
8. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
9. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 2 sensor 1. After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If sent here from another DTC diagnostic test, go to step 4 . If not sent here from another DTC diagnostic test, go to next step.
3. If any other DTCs are set, repair DTCs as necessary before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) . If no other DTCs are set, go to next step.
4. Start engine. Using scan tool, observe ECT sensor parameters. View both engine speed and HO2S bank 2 sensor 1 until engine is at normal operating temperature. Increase engine speed to 2000 RPM for 2 minutes. If HO2S bank 2 sensor 1 voltage rapidly switches from less than 325 millivolts to more than 625 millivolts, go to next step. If HO2S bank 2 sensor 1 voltage does not rapidly switch from less than 325 millivolts to more than 625 millivolts, go to step 6 .
5. Increase engine speed to 2000 RPM. Using scan tool, observe LOOP STATUS. If scan tool indicates CLOSED, no problem is indicated at this time. If scan tool does not indicate CLOSED, go to step 9 .
6. If voltage in step 4 remains within 325-625 millivolts the majority of the time, go to step 9 . If voltage does not remain within 325-625 millivolts the majority of the time, go to next step.
7. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to 10 . If connectors are okay, go to next step.
8. Check for poor connections at HO2S bank 2 sensor 1 connector. Repair connector as necessary. After repairs, go to step 10 . If connector is okay, go to next step.
9. Check for contamination sources that may have caused HO2S to fail. HO2S contamination sources include use of an incorrect RTV silicone engine sealant, contaminated fuel and excessive engine oil or coolant consumption. Repair or remove source of contamination. Replace HO2S bank 2 sensor 1. After repairs, go to next step.
10. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If engine cooling diagnostic system check has already been performed, go to next step. If engine cooling diagnostic system check has not been perform, go to «ENGINE COOLING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S08170905392001100500000) under DIAGNOSTIC SYSTEM CHECKS.
2. Check cooling fan operation. If cooling fans are not functioning properly, diagnose cooling fans as necessary. See ELECTRIC COOLING FANS - CARS article in ENGINE COOLING. If cooling fans are functioning properly, diagnose cooling system and repair as necessary.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Perform CKP system variation learn procedure. See «CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE»(ref-121492-S30360674422001083100000) under PROGRAMMING. After procedure is complete, go to next step.
3. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

CKP system variation compensating values are stored in PCM memory after a learn procedure has been performed. If actual crankshaft position system variation is not within CKP system variation compensating values stored in PCM, DTC P0300 may set. See DIAGNOSTIC AIDS in DTC P0300: ENGINE MISFIRE DETECTED.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P1360 is also set, go to next step. If DTC P1360 is not also set, go to step 5.
3. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If misfire current cyl # is incrementing for any even cylinders, go to step 6. If misfire current cyl # is not incrementing for any even cylinders, go to next step.
4. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If misfire current cyl # is incrementing for any odd cylinders, go to step 7. If misfire current cyl # is not incrementing for any odd cylinders, go to step 15.
5. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If current cyl # is incrementing for any 2 cylinders, go to step 8. If current cyl # is not incrementing for any 2 cylinders, go to step 11.
6. Locate front ICM assembly on left (front) valve cover. Inspect front ICM assembly for the following conditions: Check ICM assembly for disconnected or damaged harness connector. Check ICM assembly for a loss of power or ground. See WIRING DIAGRAMS article. Check for poor connections at ICM assembly connector. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 14.
7. Locate rear ICM assembly on right (rear) valve cover. Inspect rear ICM assembly for the following conditions: Check ICM assembly for disconnected or damaged harness connector. Check ICM assembly for a loss of power or ground. See WIRING DIAGRAMS article. Check for poor connections at ICM assembly connector. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 14.
8. If incrementing cylinders are even (cylinder No. 4 and 6), go to next step. If incrementing cylinders are not even (cylinders No. 4 and 6), go to step 10.
9. Turn ignition off. Disconnect front ICM assembly connector. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 59 (Dark Green/White wire) at PCM C2 harness connector. see scheme 2 Also measure voltage between ground and terminal No. 60 (Light Blue/White wire) at PCM C2 harness connector. If any voltage is indicated at any terminal, repair short to voltage in appropriate wire between PCM and front ICM assembly. After repairs, go to step 16. If no voltage is indicated at both terminals, go to step 15.
10. Turn ignition off. Disconnect rear ICM assembly connector. Disconnect PCM connectors PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 61 (Purple wire) at PCM C1 harness connector. see scheme 2 Also measure voltage between ground and terminal No. 22 (Red wire) at PCM C1 harness connector. If any voltage is indicated at any terminal, repair short to voltage in appropriate wire between PCM and rear ICM assembly. After repairs, go to step 16. If no voltage is indicated at both terminals, go to step 15.
11. Turn ignition off. Disconnect ICM assembly connector associated with incrementing misfire current cyl #. Connect a DVOM between ground and affected IC circuit terminal at ICM harness connector. See WIRING DIAGRAMS article. Remove fuses No. 21 (INJR 1 fuse) and No. 16 (INJR 2 fuse) from underhood fuse block. Measure frequency of affected IC circuit while cranking engine. If frequency is 1-2 Hz, go to step 13. If frequency is not 1-2 Hz, go to next step.
12. Turn ignition off. Check continuity of affected IC circuit between appropriate ICM harness connector and PCM. See WIRING DIAGRAMS article. If continuity does not exist, repair open in IC circuit. After repairs, go to step 16. If continuity exists, go to step 15.
13. Check for poor connections at ICM assembly. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to next step.
14. Replace appropriate ICM assembly. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

MISFIRE CURRENT CYL #/MISFIRE HISTORY CYL # displays on scan tool provides information that may be useful in diagnosing DTC P1359. Misfire current cyl # counter may normally display a small amount of activity, typically 0-10 counts. However, display should not increment steadily. If misfire current cyl # increments steadily for a single cylinder within IC circuit group, condition is isolated to IC circuit for specific cylinder. If misfire current cyl # increments randomly within IC circuit group, condition may be due to poor connections at PCM or a faulty PCM. If misfire current cyl # increments steadily for a cylinder bank, DTC P1360 may set. DTC P1360 may result from a loss of power or ground to ICM assembly, faulty ICM assembly connector or faulty ICM assembly.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P1359 is also set, go to next step. If DTC P1359 is not also set, go to step 5.
3. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If misfire current cyl # is incrementing for any even cylinders, go to step 6. If misfire current cyl # is not incrementing for any even cylinders, go to next step.
4. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If misfire current cyl # is incrementing for any odd cylinders, go to step 7. If misfire current cyl # is not incrementing for any odd cylinders, go to step 15.
5. With engine idling, observe MISFIRE CURRENT CYL # display on scan tool. If current cyl # is incrementing for any 2 cylinders, go to step 8. If current cyl # is not incrementing for any 2 cylinders, go to step 11.
6. Locate front ICM assembly on left (front) valve cover. Inspect front ICM assembly for the following conditions: Check ICM assembly for disconnected or damaged harness connector. Check ICM assembly for a loss of power or ground. See WIRING DIAGRAMS article. Check for poor connections at ICM assembly connector. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 14.
7. Locate rear ICM assembly on right (rear) valve cover. Inspect rear ICM assembly for the following conditions: Check ICM assembly for disconnected or damaged harness connector. Check ICM assembly for a loss of power or ground. See WIRING DIAGRAMS article. Check for poor connections at ICM assembly connector. If any problems are found, repair as necessary. After repairs, go to step 16. If no problems are found, go to step 14.
8. If incrementing cylinders are even (cylinder No. 2 and 8), go to next step. If incrementing cylinders are not even (cylinders No. 2 and 8), go to step 10.
9. Turn ignition off. Disconnect front ICM assembly connector. Disconnect PCM connectors PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 22 (Red/White wire) at PCM C2 harness connector. see scheme 2 Also measure voltage between ground and terminal No. 61 (Purple/White wire) at PCM C2 harness connector. If any voltage is indicated at any terminal, repair short to voltage in appropriate wire between PCM and front ICM assembly. After repairs, go to step 16. If no voltage is indicated at both terminals, go to step 15.
10. Turn ignition off. Disconnect rear ICM assembly connector. Disconnect PCM connectors PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 21 (Light Blue wire) at PCM C2 harness connector. see scheme 2 Also measure voltage between ground and terminal No. 62 (Dark Green wire) at PCM C2 harness connector. If any voltage is indicated at any terminal, repair short to voltage in appropriate wire between PCM and rear ICM assembly. After repairs, go to step 16. If no voltage is indicated at both terminals, go to step 15.
11. Turn ignition off. Disconnect ICM assembly connector associated with incrementing misfire current cyl #. Connect a DVOM between ground and affected IC circuit terminal at ICM harness connector. See WIRING DIAGRAMS article. Remove fuses No. 21 (INJR 1 fuse) and No. 16 (INJR 2 fuse) from underhood fuse block. Measure frequency of affected IC circuit while cranking engine. If frequency is 1-2 Hz, go to step 13. If frequency is not 1-2 Hz, go to next step.
12. Turn ignition off. Check continuity of affected IC circuit between appropriate ICM harness connector and PCM. See WIRING DIAGRAMS article. If continuity does not exist, repair open in IC circuit. After repairs, go to step 16. If continuity exists, go to step 15.
13. Check for poor connections at ICM assembly. Repair connector as necessary. After repairs, go to step 16. If connector is okay, go to next step.
14. Replace appropriate ICM assembly. After repairs, go to step 16.
15. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
16. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

MISFIRE CURRENT CYL #/MISFIRE HISTORY CYL # displays on scan tool provides information that may be useful in diagnosing DTC P1360. Misfire current cyl # counter may normally display a small amount of activity, typically 0-10 counts. However, display should not increment steadily. Misfire history cyl # will display a very large number for circuits with largest failure occurrence.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Allow engine to reach normal operation temperature. Using scan tool, monitor specific DTC information for DTC P1372. If DTC P1372 sets, turn ignition off and go to step 4. If DTC P1372 does not set, go to next step.
3. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S18455388012001100500000).
4. Turn ignition on. Using scan tool, command TIME MODE B. Start engine. Raise and support vehicle. Wiggle CKP sensor "B" wiring harness and connector. see scheme 7 Using scan tool, monitor specific DTC information for DTC P0386. If DTC P0386 sets, go to «DTC P0386: CRANKSHAFT POSITION SENSOR "B" PERFORMANCE»(ref-121492-S13471588722001092600000). If DTC P0386 does not set, turn ignition off and go to next step.
5. Turn ignition on. Using scan tool, command TIME MODE A. Start engine. Raise and sport vehicle. Wiggle CKP sensor "A" wiring harness and connector. see scheme 7 Using scan tool, monitor specific DTC information for DTC P0336. If DTC P0336 sets, go to «DTC P0336: CRANKSHAFT POSITION SENSOR "A" PERFORMANCE»(ref-121492-S02953922882001091900000). If DTC P0336 does not set, go to next step.
6. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

If DTC P1372 and both intermittent DTCs P0336 and P0386 are set, check what time mode you are in to determine which sensor is good. When diagnosing CKP sensors, it may be necessary to enable a specific decode mode (ANGLE, TIME A or TIME B). In order to enable a specific crank decode, use scan tool and perform the following

1. Turn ignition on.
2. Select ENGINE OUTPUT CONTROLS.
3. Select CRANK POSITION SENSING DECODE mode.
4. Select desired mode (ANGLE, TIME A or TIME B) by pressing SELECT STATE.
5. Command decode mode by pressing COMMAND STATE.

The commanded state remains valid for current ignition cycle. A specific decode mode cannot be commanded with engine running, or after commanding a desired decode mode. In order to command a different decode mode, ignition must be cycled off and on. For intermittent faults, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

If powertrain diagnostic system check has already been performed, perform anti-lock brake diagnostic system check. See DIAGNOSTIC SYSTEM CHECK in ANTI-LOCK/TCS - BOSCH 5.3 - C, G, H & K BODIES article in BRAKES. If powertrain diagnostic system check has not been performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM CHECKS.

If DTC P1380 is set, it indicates that ABS/TCS system has detected a malfunction which will not allow EBTCM to transmit the correct rough road data to the PCM.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, select CHASSIS APPLICATION and attempt to display ABS data. If ABS data can be displayed, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If ABS data cannot be displayed, perform anti-lock brake diagnostic system check. See DIAGNOSTIC SYSTEM CHECK in ANTI-LOCK/TCS - BOSCH 5.3 - C, G, H & K BODIES article in BRAKES.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Using scan tool, check EGR position sensor parameter. If scan tool indicates zero percent, go to next step. If scan tool does not indicate zero percent, go to step 5.
3. Using scan tool, command EGR valve from zero percent to 100 percent. If desired EGR position remains close to EGR position sensor at all commanded positions, go to next step. If desired EGR position does not remain close to EGR position sensor at all commanded positions, go to step 6.
4. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-121492-S10876787282001100500000).
5. Disconnect EGR valve connector. (Scheme 7) Turn ignition on. Using scan tool, observe EGR position sensor parameter. If scan tool indicates zero percent, go to next step. If scan tool does not indicate zero percent, go to step 9.
6. Measure voltage between terminal "B" (Black wire) and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 8.
7. Connect a 3-amp fused jumper wire between terminal "C" (Brown wire) and terminal "D" (Gray/Black wire) at EGR valve harness connector. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is about 100 percent, go to step 13. If EGR position is not about 100 percent, go to step 11.
8. Measure voltage between ground and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to step 10. If voltage is not about 5 volts, go to step 12.
9. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal "C" (Brown wire) at EGR valve harness connector. If any voltage is indicated, repair short to voltage in Brown wire between EGR valve and PCM. After repairs, go to step 17. If no voltage is indicated, go to step 14.
10. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Black wire between terminal "B" at EGR valve harness connector and terminal No. 12 at PCM C2 harness connector. see scheme 2and see scheme 10. If continuity does not exist, repair open in Black wire. After repairs, go to step 17. If continuity exists, go to step 14.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe terminal "C" (Brown wire) at EGR valve harness connector. see scheme 10 If test light illuminates, repair short to ground in Brown wire between EGR valve and PCM. After repairs, go to step 17. If test light does not illuminate, go to step 15.
12. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check 5-volt reference circuit (Gray/Black wire) as follows: Check for open or short to ground in Gray/Black wire between terminal "D" at EGR valve harness connector and terminal No. 50 at PCM C2 harness connector. see scheme 2and see scheme 10. Turn ignition on. Using a test light connected to ground, probe terminal No. 50 (Gray/Black wire) at PCM C2 harness connector. Test light should not illuminate. If test light illuminates, Gray/Black wire is shorted to voltage. If any problems are found, repair as necessary. After repairs, go to step 17. If no problems are found, go to step 15.
13. Check for poor connections at EGR valve connector. Repair connector as necessary. After repairs, go to step 17. If connector is okay, go to step 16.
14. Check for poor connections at PCM connectors. Repair connectors as necessary. After repairs, go to step 17. If connectors are okay, go to step 16.
15. Replace EGR valve. After repairs, go to step 17.
16. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
17. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Check for excessive deposits on EGR valve pintle and seat. Remove EGR valve and check for deposits that may interfere with EGR valve pintle extending completely or cause pintle to stick.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Ensure engine is at normal operating temperature. Turn all accessories off. Using scan tool, monitor HO2S bank 1 sensor 1 voltage. Using scan tool, enable AIR system. Observe and record HO2S voltage while AIR system is enabled. If voltage drops to less than 350 millivolts, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If voltage does not drop to less than 350 millivolts, go to next step.
3. Turn ignition off. Disconnect vacuum hose from bank 1 (rear cylinder head) shutoff valve. Connect a vacuum gauge to disconnected vacuum hose. Start engine and allow it to idle. Using scan tool, select OUTPUT CONTROLS and enable AIR system. If vacuum is indicated on vacuum gauge, go to next step. If no vacuum is indicated on vacuum gauge, go to step 5 .
4. Inspect all AIR pipes and hoses. Check for blockage, poor connections and damage. Check components for evidence of heat damage. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to step 6 .
5. Replace vacuum hose between AIR solenoid and bank 1 AIR shutoff valve. After repairs, go to step 7 .
6. Replace bank 1 AIR shutoff valve. After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Start engine. Ensure engine is at normal operating temperature. Turn all accessories off. Using scan tool, monitor HO2S bank 2 sensor 1 voltage. Using scan tool, enable AIR system. Observe and record HO2S voltage while AIR system is enabled. If voltage drops to less than 350 millivolts, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If voltage does not drop to less than 350 millivolts, go to next step.
3. Turn ignition off. Disconnect vacuum hose from bank 2 (rear cylinder head) shutoff valve. Connect a vacuum gauge to disconnected vacuum hose. Start engine and allow it to idle. Using scan tool, select OUTPUT CONTROLS and enable AIR system. If vacuum is indicated on vacuum gauge, go to next step. If no vacuum is indicated on vacuum gauge, go to step 5 .
4. Inspect all AIR pipes and hoses. Check for blockage, poor connections and damage. Check components for evidence of heat damage. If any problems are found, repair as necessary. After repairs, go to step 7 . If no problems are found, go to step 6 .
5. Replace vacuum hose between AIR solenoid and bank 2 AIR shutoff valve. After repairs, go to step 7 .
6. Replace bank 2 AIR shutoff valve. After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. If DTC P0443, P0449, P0452 or P0453 is also set, diagnose DTC(s) before continuing with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000). If DTC P0443, P0449, P0452 or P0453 is not also set, go to next step.
3. Remove the fuel fill cap. Ensure ignition is on. Using scan tool, monitor fuel tank pressure. If fuel tank pressure is -.5 to +.5 in. H2O, go to next step. If fuel tank pressure is not -.5 to +.5 in. H2O, go to «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT HIGH VOLTAGE»(ref-121492-S23110401702001092800000).
4. Disconnect EVAP purge pipe from EVAP canister purge valve. (Scheme 7) Install a vacuum gauge to EVAP canister purge valve purge port. Disconnect EVAP canister purge valve connector. Monitor vacuum on vacuum gauge. Start engine and allow it to idle. Increase engine speed 1200-1500 RPM. If vacuum gauge indicates an increase in vacuum, go to next step. If vacuum gauge does not indicate an increase in vacuum, see «DIAGNOSTIC AIDS»(ref-121492-S34688933772001082900000).
5. Replace EVAP canister purge valve. After repairs, go to next step.
6. Using scan tool, monitor fuel tank pressure. Start engine and allow it to idle for 30 seconds. If fuel tank pressure is -.5 to +.5 in. H2O, go to next step. If fuel tank pressure is not -.5 to +.5 in. H2O, go to step 3.
7. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve or by a temporary blockage in EVAP canister purge valve.

1. If air conditioning diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «AIR CONDITIONING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S29233993442001101300000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Using scan tool, select DIM A/C information from data list. Using scan tool, observe evaporator temperature parameter. If scan tool indicates temperature is -34 to 261°F (-37 to 127°C), no problem is indicated at this time. Fault may be intermittent. If scan tool does not indicate temperature is -34 to 261°F (-37°C to 127°C), go to next step.
3. Turn ignition off. Disconnect A/C refrigerant low temperature sensor. Sensor is located in suction hose of A/C compressor and has a 2-pin connector with Black/White and Gray wires. Turn ignition on. Using scan tool, observe evaporator temperature parameter. If scan tool indicates temperature is less than -34°F (37°C), go to next step. If scan tool does not indicate temperature is less than -34°F (37°C), go to 5.
4. Turn ignition off. Connect a 3-amp fused jumper wire between Black/White and Gray wires at A/C refrigerant low temperature sensor harness connector. Turn ignition on. Using scan tool, observe evaporator temperature parameter. If scan tool indicates temperature is more than 261°F (127°C), go to step 8. If scan tool does not indicate temperature is more than 261°F (127°C), go to step 6.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Using a test light connected to positive battery voltage, probe Gray wire at A/C refrigerant low temperature sensor harness connector. If test light illuminates, repair short to ground in Gray wire between A/C refrigerant low temperature sensor and DIM. After repairs, go to step 12. If test light does not illuminate, go to step 9.
6. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Measure voltage between ground and Gray wire at A/C refrigerant low temperature sensor harness connector. If any voltage is indicated, repair short to voltage in Gray wire between A/C refrigerant low temperature sensor and DIM. After repairs, go to step 12. If no voltage is indicated, go to next step.
7. Check continuity of Black/White wire between A/C refrigerant low temperature sensor harness connector and terminal A6 at DIM C2 harness connector. (Scheme 12) If continuity does not exist, repair open in Black/White wire. After repairs, go to step 12. If continuity exists, go to step 9.
8. Check for poor connections A/C refrigerant low temperature sensor connector. Repair connector as necessary. After repairs, go to step 12. If connector is okay, go to step 10.
9. Check for poor connections at DIM connectors. Repair connectors as necessary. After repairs, go to step 12. If connectors are okay, go to step 11.
10. Replace A/C refrigerant low temperature sensor. See REMOVAL & INSTALLATION in AUTOMATIC A/C-HEATER SYSTEMS - AURORA article in AIR CONDITIONING & HEATING. After repairs, go to step 12.
11. Replace DIM. See REMOVAL & INSTALLATION in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. After repairs, go to next step.
12. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

Scheme 12

If DTC P1536 is stored as a history code, it indicates that the DIM did receive a high engine coolant temperature message from the PCM. Interrupting A/C compressor operation can occur as a normal function to protect the engine from overheating, as when pulling a trailer up a hill. If the condition occurs frequently, check the following for a possible cause

1. Check for inoperative engine cooling fans.
2. Check for debris in front of A/C condenser.
3. Check for missing or out of location radiator or A/C condenser air shields.
4. Check for low coolant level.
5. Check for inoperative thermostat.
6. Check for water pump failure.
7. Check PCM for current or history engine coolant temperature sensor DTCs. If any DTCs are set, repair as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .
8. Check for trailer weight exceeding 1000 lbs. (454 kg) in extreme high ambient temperatures.
9. Check for any aftermarket products affecting cooling system performance.

1. If air conditioning diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «AIR CONDITIONING DIAGNOSTIC SYSTEM CHECK»(ref-121492-S29233993442001101300000) under DIAGNOSTIC SYSTEM CHECKS.
2. Ensure ignition is on. Wait at least one minute for the A/C system pressure to equalize. Using scan tool, check for current and history DTCs in DIM menu. If DTC P1540 is stored as current, go to next step. If DTC P1540 is not stored as current, see «DIAGNOSTIC AIDS»(ref-121492-S13151979032001101500000) .
3. Connect A/C service gauges to high and low pressure ports. Note A/C system pressure. Using scan tool, select DIM A/C information from data list and observe A/C pressure parameter. Note pressure reading. Compare scan tool reading with reading noted from A/C service gauges. If readings are within plus or minus 20 psi, check A/C system performance. See A/C SYSTEM PERFORMANCE under SYSTEM TESTS in AUTOMATIC A/C-HEATER SYSTEMS - AURORA article in AIR CONDITIONING & HEATING. If readings are not within plus or minus 20 psi, go to next step.
4. Replace A/C pressure sensor. Sensor is located in discharge hose of A/C compressor. After repairs, go to next step.
5. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
6. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

If DTC P1540 is stored as a history code it indicates that the DIM received a high A/C refrigerant pressure message from the PCM. This code could also be caused by an intermittent short to voltage on the A/C refrigerant pressure sensor signal circuit which would cause the PCM to set DTC P0530. DTC may also be the result of an actual A/C refrigerant over-pressure condition. It is possible for the refrigerant system pressure to exceed 430 psi (2968 kPa) during extended engine idle speed with A/C on when ambient temperatures are greater than 105°F (41°C). This could be caused by the following

1. Overcharged A/C system.
2. Failed A/C refrigerant pressure sensor.
3. Blockage in a refrigerant line.
4. Debris in front of the A/C condenser.
5. Radiator or A/C condenser air shields missing or out of location.
6. Inoperative engine cooling fans.
7. Extended periods at idle in city traffic followed by rapid acceleration.
8. Aftermarket products affecting cooling system performance.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Turn ignition on. Release brake pedal. Using scan tool, observe EXTENDED TRAVEL BRAKE parameter. If scan tool displays RELEASED, go to next step. If scan tool does not display RELEASED, go to step 5.
3. Depress brake pedal more than half-way down. If scan tool displays APPLIED, no problem is indicated at this time. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article. If scan tool does not display APPLIED, go to next step. NOTE: Brake switch consists of extended travel brake switch and TCC brake switch.
4. Disconnect brake switch connector. If scan tool displays APPLIED, go to step 13. If scan tool does not display APPLIED, go to step 8.
5. Disconnect brake switch connector. Using a test light connected to ground, probe Pink wire at brake switch harness. If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
6. Connect a 3-amp fused jumper wire between Gray and Pink wires at brake switch harness connector. Using scan tool, observe extended travel brake switch parameter. If scan tool displays RELEASED, go to step 10. If scan tool does not display RELEASED, go to next step.
7. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check continuity of Gray wire between brake switch harness connector and terminal No. 44 at PCM C1 harness connector. see scheme 2 If continuity does not exist, repair open Gray wire. After repairs, go to step 14. If continuity exists, go to step 9.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Measure voltage between ground and terminal No. 44 (Gray wire) at PCM C1 harness connector. see scheme 2 If any voltage is indicated, repair short to voltage in Gray wire between PCM and brake switch. After repairs, go to step 14. If no voltage is indicated, go to step 12.
9. Check for poor connections at PCM connectors. Repair connector as necessary. After repairs, go to step 14. If connectors are okay, go to step 12.
10. Check for poor connections at brake switch connector. Repair connector as necessary. After repairs, go to step 14. If connector is okay, go to step 13.
11. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check ignition 1 voltage circuit (Pink wire) and extended travel brake switch signal circuit (Gray wire) as follows: Check continuity of Pink wire between output side of fuse No. 11 (IGN 1 fuse) in underhood fuse block and brake switch harness connector. Continuity should exist. If continuity does not exist, Pink wire is open. Using a test light connected to positive battery voltage, probe Pink wire at brake switch harness connector. Test light should not illuminate. If test light illuminates, Pink wire is shorted to ground. Using a test light connected to positive battery voltage, probe Gray wire at brake switch harness connector. Test light should not illuminate. If test light illuminates, Gray wire is shorted to ground between brake switch and terminal No. 44 at PCM C1 harness connector. see scheme 2 Repair wiring as necessary. After repairs, go to step 14.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to step 14.
13. Replace brake switch. After repairs, go to next step.
14. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, see «DIAGNOSTIC AIDS»(ref-121492-S08725346282001082900000) . If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .

This DTC informs the technician that the customer has initiated the customer snapshot function. PCM will store up to 6 snapshots in the failure records before over-writing the first recorded snapshot. The customer snapshot function may help to diagnose conditions which could not be duplicated during previous diagnosis. If no other DTCs are set, fault is most likely intermittent.

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Check PCM and engine grounds. Ensure grounds are clean and tight. See WIRING DIAGRAMS article. If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to next step.
4. Turn ignition off. Disconnect EGR valve connector. see scheme 5 Turn ignition on. Measure voltage between ground and terminal "D" (Gray/Black wire) at EGR valve harness connector. see scheme 10 If voltage is about 5 volts, go to step 6. If voltage is not about 5 volts, go to next step.
5. If voltage is more than 5 volts, go to step 9. If voltage is less than 5 volts, go to step 7.
6. Reconnect EGR valve connector. Disconnect TP sensor connector. see scheme 5 Measure voltage between ground and Gray wire at TP sensor harness connector. If voltage is about 5 volts, no problem is indicated at this time. Fault may be intermittent. If voltage is not about 5 volts, go to step 10.
7. Monitor DVOM while disconnecting all other devices (TP and MAP sensors) connected to 5-volt reference 1 circuit one at a time. If voltage changes when one of the components is disconnected, replace affected component. After repairs, go to step 13. If voltage does not change when one of the components is disconnected, go to next step.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Check TP sensor, MAP sensor and EGR valve 5-volt reference 1 circuit for a short to ground or a short to any sensor low reference circuit. See WIRING DIAGRAMS article. If any problems are found, repair wiring as necessary. After repairs, go to step 13. If no problems are found, go to step 12.
9. Turn ignition off. Disconnect PCM harness connector. PCM is located in engine compartment, inside air filter housing. Turn ignition on. Check TP sensor, MAP sensor and EGR valve 5-volt reference 1 circuit for short to voltage. See WIRING DIAGRAMS article. Also check for short to voltage in MAP sensor signal circuit (Light Green wire) between MAP sensor harness connector and terminal No. 23 at PCM C1 harness connector. see scheme 2 If any problems are found, repair as necessary. After repairs, go to step 13. If no problems are found, go to step 12.
10. Turn ignition off. Check for continuity between terminal "D" (Gray/Black wire) and terminal "E" (Red wire) at EGR valve harness connector. see scheme 10 If continuity exists, Gray/Black and Red wires are shorted together. Repair wiring as necessary. After repairs, go to step 13. If continuity does not exist, go to next step.
11. Replace EGR valve. After replacing EGR valve, go to step 13.
12. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000). After repairs, go to next step.
13. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000).

1. If powertrain diagnostic system check has already been performed, go to next step. If powertrain diagnostic system check has not been performed, go to «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-121492-S39227106492001082900000) under DIAGNOSTIC SYSTEM CHECKS.
2. Using scan tool, observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria, or as close to recorded FREEZE FRAME/FAILURE RECORDS data as possible. If DTC resets, go to next step. If DTC does not reset, fault may be intermittent. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.
3. Check PCM and engine grounds. Ensure grounds are clean and tight. See WIRING DIAGRAMS article. If any problems are found, repair as necessary. After repairs, go to step 17 . If no problems are found, go to next step.
4. Turn ignition off. Disconnect A/C pressure sensor connector. Sensor is located in discharge hose of A/C compressor. Turn ignition on. Measure voltage between ground and Gray wire at A/C pressure sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not about 5 volts, go to step 6 .
5. Turn ignition off. Reconnect A/C pressure sensor connector. Disconnect FTP sensor connector. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. Measure voltage between ground and Gray wire at FTP sensor harness connector. If voltage is about 5 volts, no problem is indicated at this time. Fault may be intermittent. If voltage is not about 5 volts, go to step 13 .
6. If voltage is more than 5 volts, go to next step. If voltage is less than 5 volts, go to step 8 .
7. Turn ignition off. Disconnect A/C pressure sensor connector. Connect DVOM between ground and Gray wire at A/C pressure sensor harness connector. Disconnect PCM connectors. PCM is located in engine compartment, inside air filter housing. Turn ignition on. If no voltage is indicated, go to step 15 . If any voltage is indicated, go to step 12 .
8. Ensure DVOM is still connected as in step 4 . Disconnect FTP sensor connector. FTP sensor is located on top of fuel tank and can be accessed through an inspection panel in trunk. Turn ignition on. If voltage is about 5 volts, go to step 14 . If voltage is not about 5 volts, go to next step.
9. Turn ignition off. Check for continuity between Gray and White wires at FTP sensor harness connector. Also check for continuity between Gray and Black wires at A/C pressure sensor harness connector. If either reading indicates continuity, go to step 11 . If both readings indicate no continuity exists, go to next step.
10. Check for continuity between ground and Gray wire at FTP sensor harness connector. Also check for continuity between ground and Gray wire at A/C pressure sensor harness connector. If either reading indicates continuity exists, go to next step. If both readings indicate continuity does not exist, go to step 15 .
11. Repair shorted wiring as necessary. After repairs, go to step 17 .
12. Repair short to voltage as necessary. After repairs, go to step 17 .
13. Replace A/C pressure sensor. After repairs, go to step 17 .
14. Replace FTP sensor. After repairs, go to step 17 .
15. Turn ignition off. Ensure PCM is disconnected. Check FTP sensor and A/C pressure sensor 5-volt reference circuit (Gray wire) for an open, short to ground or poor connection at PCM connector. See WIRING DIAGRAMS article. If any problems are found, repair as necessary. After repairs, go to step 17 . If no problems are found, go to next step.
16. Replace PCM. Program replacement PCM. See «PROGRAMMING»(ref-121492-S36116474272001082900000) . After repairs, go to next step.
17. Turn ignition off. Reconnect all disconnected connectors. Turn ignition on. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running the DTC as specified in code enable criteria. If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
18. Using scan tool, check for any other DTCs that are set. If no other DTCs are set, test is complete. If any other DTCs are set, repair DTCs as necessary. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-121492-S42745357372001083100000) .