Engine Controls Self-Diagnostics - 3.4L: Diagnosis Pontiac Montana I

ON-BOARD DIAGNOSTICS

PCM is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, PCM will store a Diagnostic Trouble Code (DTC) and, if code is emission related, it will illuminate the Malfunction Indicator Light (MIL) located on instrument cluster.

There are 2 paths for accessing on-board diagnostics. It is necessary to access information through both paths, as each path presents some different information.

1. Generic OBD-II This provides all generic codes and some OEM codes, serial data required for generic OBD-II and some OEM PIDs, monitor status, pending codes and FREEZE FRAME.
2. OEM All DTCs, all PIDs, failure records, enhanced scan tool information and all other OEM scanner functions.

Intermittent Trouble Code Determination

Note. Intermittent is a DTC or symptom, with a condition that cannot be duplicated. Before attempting to diagnose an intermittent condition, ensure powertrain diagnostic system check has been performed. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK .

1. Duplicating Failure Conditions Freeze frame and failure records data contain the conditions present when DTC set. Review and record freeze frame and failure records data. Clear DTCs using scan tool. Turn ignition off and wait 15 seconds. Operate the vehicle under the same conditions noted in freeze frame and failure records data, as closely as possible. Vehicle must also be operating within conditions for running the DTC. See CODE ENABLE CRITERIA in appropriate DTC test. Monitor DTC Status for the DTC being tested. The scan tool will indicate Ran, when the enabling conditions have been satisfied long enough for the DTC to run. The scan tool will also indicate whether the DTC passed or failed. An alternate method is to drive the vehicle with the DVOM connected to a suspected circuit. An abnormal reading on the DVOM when the problem occurs, may help you locate the problem.
2. Wiring Harness & Electrical Connectors Many intermittent open or shorted circuits come and go with harness or connector movement caused by vibration, engine torque, and bumps or rough road condition. Test for intermittents by moving related connectors and wiring while monitoring appropriate scan tool data. With engine running, move related connectors and wiring while monitoring engine operation. Verify if harness or connector movement affects scan tool data display, component or system operation, or engine operation. Repair condition as necessary. Intermittents caused by harness connectors are usually caused by poor electrical connections, terminal tension and/or wiring problems. Check for poor mating of connector halves, terminals backed out or not fully seated in connector body, improperly formed or damaged terminals or poor terminal tension. Also, check for poor terminal-to-wire connections including terminals crimped over insulation, swollen and stiff sections of wire in suspect circuits, wires that are broken inside the insulation, pinched, cut or rubbed-through wiring, or wiring that is in contact with hot exhaust components. Repair condition as necessary.
3. Control Module & Component Power & Grounds Many vehicles have multiple circuits supplying power to control modules. Other components may have separate power circuits that may also need to be tested. Check connections at module or component connectors, fuses, and any intermediate connections between power source and the module or component. Ensure that the circuit can carry the current necessary to operate the component. Test all control module ground and system ground circuits. Control module may have multiple ground circuits. Other components may have separate grounds that may also need to be tested. Check grounds for clean and tight connections at the ground connection. Check the connections at the component and in splice packs, where applicable.
4. Temperature Sensitivity An intermittent condition may occur when a component or connection reaches normal operating temperature. Condition may occur only when component or connection is cold or hot. Use FREEZE FRAME/FAILURE RECORDS, scan tool snapshot or vehicle data recorder to help diagnose this type of intermittent. If intermittent is related to heat, check for high ambient temperatures, underhood or engine generated heat, circuit generated heat due to a poor connection, or high electrical load. If intermittent is related to cold, check for low ambient temperatures or water intrusion.
5. Electromagnetic Interference & Electrical Noise Some electrical components or circuits are sensitive to Electromagnetic Interference (EMI) or other types of electrical noise. Check for misrouted wiring that is too close to high voltage or high current devices. Check for wires that are too close to secondary ignition components, electrical motors or the generator. Check for non-factory or aftermarket add-on accessories such as lights, 2-way radios, amplifiers, electric motors, remote starters, alarm systems, or cellular phones. Test for open diode across AC compressor. Some relays may contain a clamping diode. Ensure generator is operating properly.

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. Diagnostic system check must be performed before using specific DTC testing procedure. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) .
2. If no DTCs are present and a driveability problem exists, refer to SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article. Doing so will help identify proper system or component to check in appropriate SYSTEM & COMPONENT TESTING article.
3. After necessary repairs are made, clear DTCs, verify vehicle will enter "closed-loop" operation and ensure DTC does not reset.

RETRIEVING DIAGNOSTIC TROUBLE CODES

DTCs are retrieved using a Tech 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See POWERTRAIN DIAGNOSTIC SYSTEM CHECK. (Scheme 1) DLC is located below left side of dash.

Scheme 1

POWERTRAIN DIAGNOSTIC SYSTEM CHECK

Note. Check for applicable Technical Service Bulletins (TSBs) before proceeding. DO NOT perform the following procedure if driveability conditions are not present. DO NOT turn ignition off during the following procedure or clear DTCs unless instructed to do so.

1. If engine does not crank, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS. Ensure battery is fully charged and cables are clean and tight. Ensure PCM grounds are clean, tight, and in proper location. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to next step.
2. Turn ignition on, with engine off. Using scan tool, attempt to establish communication with PCM. If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, perform SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article.
3. Attempt to start engine. If engine starts and idles, go to next step. If engine does not start, go to appropriate NO-START diagnosis in BASIC DIAGNOSTIC PROCEDURES article.
4. Using scan tool, select DTC display function for PCM, VTD, IP Cluster and EBCM. If scan tool displays any DTCs, go to next step. If scan tool does not display any DTCs, go to step 9 .
5. Using scan tool, save or capture powertrain DTC information or store information. After saving DTC information, go to next step.
6. If scan tool displays DTCs which begin with a "U", go to appropriate BODY CONTROL MODULES article. If no "U" series DTC are displayed, go to next step.
7. If DTC P0601 or P0602 is set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0601 or P0602 is not set, go to next step.
8. If scan tool displays DTC P0560 or P0620 diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0560 or P0620 is not set, go to next step.
9. If problem is related to an automatic transmission problem, diagnose transmission. If problem is not related to the automatic transmission, go to next step.
10. If problem is with I/M testing, verify if vehicle meets the criteria that complies with local area requirements. Repair as necessary. If problem is other than I/M testing, go to next step.
11. Check for cause of hard start, surges/chuggles, lack of power, sluggishness, or sponginess. Check for cause of detonation/spark knock, hesitation, sag, stumble, cuts out/misses, poor fuel economy, poor fuel fill quality, rough, unstable, or incorrect idle and stalling. Check for cause of dieseling/run-on, backfire, MIL inoperative, or MIL is always on. Repair as necessary. If no problem is found, problem is intermittent.

CLEARING DIAGNOSTIC TROUBLE CODES

There are 3 methods to clear DTCs.

Scan Tool

Scan tool is preferable way to clear DTC information. FREEZE FRAME and failure record data will also be cleared. PCM adaptive learning and system monitors will only be cleared for those system which had a stored DTC.

SCAN TOOL USAGE

Scan tool is a specialized tester which, when connected to DLC, can be used to diagnose on-board computer control systems by providing instant access to circuit voltage information without need to crawl under dash or hood to backprobe sensors and connectors.

Scan tool reduces diagnostic time dramatically by furnishing input data (voltage signals) which can be compared to specification parameters. They may also furnish information on output device (solenoids and motors) status. However, status parameters only indicate output signals have been sent to devices by PCM; they do not indicate whether devices have responded properly to signal. Verify proper response at output device using a voltmeter or test light.

A problem may exist even if DTCs are not present. Many driveability problems occur without setting DTCs.

Using a scan tool is the easiest method of checking sensor specifications and other data parameters. Scan tool is also useful in finding intermittent wiring problems by wiggling wiring harnesses and connections (key on, engine off) while observing data parameters.

Note. If erroneous voltage signals are suspected, verify tester information using a digital voltmeter and wiring schematic. If nonexistent codes are displayed, DO NOT use scan tool for diagnosis. Contact tester manufacturer for additional information.

Scan Tool Display

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

The following are Tech 2 scan tool sub-menus in the DTC INFO and SPECIFIC DTC modes

1. DTC INFO MODE Used to search for specific type of stored DTC information. There are 7 choices in this mode. Technician may be instructed to test DTCs in a certain manner. Follow the affected DTC test procedures. To get complete description of any status, hit ENTER key before pressing the desired "F" key.
2. DTC STATUS This selection will display any DTCs that have not run during the current ignition cycle or have reported a test failure during this ignition up to a maximum of 33 DTCs. A DTC test that runs and passes will cause affected DTC to be removed from scan tool screen.
3. FAIL THIS IGN. This selection will display all DTCs that have failed during the present ignition cycle.
4. HISTORY This selection will display only DTCs that are stored in the control module's history memory. It will not display Type "D" DTCs. It 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.
5. LAST TEST FAIL This selection will only display DTCs that have 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.
6. MIL REQUEST This selection will only display DTCs that are requesting MIL illumination. Type "C" DTCs cannot be displayed using this option. This selection will report Type "B" DTCs only after MIL illumination has been requested.
7. NOT RUN SCC Not Run Since Code Clear option will display up to 33 DTCs that have not run since DTCs were last cleared. Since any displayed DTCs have not run, their condition (passing or failing) is unknown.
8. TEST FAIL SCC Test Fail Since Code Clear selection will display all active and history DTCs that have reported a test failure since the last time DTCs were cleared. DTCs that last failed more than 40 warm-up cycles before this option is selected will not be displayed.
9. FAILED SINCE CLEAR This message indicates the DTC has failed at least once within the last 40 warm-up cycles since the last time DTCs were cleared.
10. NOT RUN SINCE CL. Not Run Since Cleared message indicates that the selected diagnostic test has not run since the last time DTCs were cleared. Therefore, the diagnostic test status (passed or failed) is unknown. After DTCs are cleared, this message will continue to be displayed until the diagnostic test runs.
11. NOT RUN THIS IGN. Not Run This Ignition message indicates the selected diagnostic test has not run this ignition cycle.
12. TEST RAN AND PASSED This message indicates the selected diagnostic test has: Passed the last test. Ran and passed during this ignition cycle. Ran and passed since DTCs were last cleared. Test has not failed since DTCs were last cleared. If this message is displayed, repair is complete. If FAILED THIS IGN. message is displayed, repair is incomplete and further diagnosis is required.

Diagnostic Procedures

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
2. Preprogram scan tool with vehicle information before ignition is turned on. Ensure vehicle meets conditions under «DESCRIPTION»(ref-117480-S28676221272001091200000) . Turn off all accessories, such as A/C, blower fan, etc. Set vehicle parking brake. Ensure transmission is in Park (A/T) or Neutral (M/T). Start and operate engine at idle for 2 minutes, then go to next step.
3. Accelerate at part throttle to 55 MPH with this speed maintained until engine reaches operating temperature. This may be up to 8-10 minutes depending on start-up coolant temperature. Continue operation under these conditions for an additional 6 minutes, then go to next step.
4. Reduce vehicle speed to 45 MPH, maintain this speed for one additional minute. Four decelerations of 25 seconds each from 45 MPH while maintaining the following criteria: Throttle is closed. No brake application. No clutch actuation on M/T. No manual downshift Vehicle speed remains greater than 25 MPH. After each deceleration period, vehicle is returned to 45 MPH under part throttle acceleration and speed is maintained for 15 seconds. After performing procedure, go to next step.
5. Acceleration at part throttle to 45-55 MPH with this speed maintained for 2 minutes. Deceleration to zero MPH. Operate engine at idle for 2 minutes while service brake is depressed, A/T in Drive. M/T in Neutral with clutch pedal depressed. After performing procedure, go to next step.
6. Using scan tool, observe I/M System Status display. If all I/M System Status indicators update to YES, go to next step. If all I/M system status indicators do 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, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If scan tool does not indicate emission related DTCs, system is okay.

Diagnostic Aids

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

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

Scan tool can be used to monitor each I/M SYSTEM STATUS indicator during I/M complete system set procedure. When all of indicators for a test step have updated to YES, testing can move on to next step even if remaining portion of test is not complete. For example, step 3 is designed to run the EVAP, secondary Air Injection (AIR), and HO2S tests. Procedure instructs technician to operate vehicle in enable conditions for 6 minutes. If all 3 tests have updated to YES within 4 minutes, it is not necessary to continue with enable conditions and testing can advance to next step.

1. Perform «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. If DTC or driveability concerns were repaired using powertrain diagnostic system check, go to step 3 . If no DTC or driveability concerns were 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, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-117480-S37303393582001091200000) . If reprogramming or repair service is 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, see «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-117480-S37303393582001091200000) . If only one test indicates a NO status, go to appropriate I/M system set procedure for indicated system.

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.

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
2. Ensure vehicle is within the conditions for running this test. See «ENABLE CRITERIA»(ref-117480-S04095866732001091200000) . Turn off all accessories (e.g., A/C, blower fan, etc.). Start and allow engine to idle for 2 minutes. In order for Active Test to run, vehicle must operate in the following conditions: Accelerate at part throttle to 45 MPH and maintain speed for 3 minutes or until I/M system status indicator updates to YES. Using scan tool, monitor I/M SYSTEM STATUS. If CATALYST SYSTEM STATUS is YES, go to step 5 . If CATALYST SYSTEM STATUS is not YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, observe the Not Ran Since Code Cleared display. Determine which of DTCs required for a YES status has not run. Enter DTC number in Specific DTC menu of scan tool. Operate vehicle within conditions for running the DTC. See «ENABLE CRITERIA»(ref-117480-S04095866732001091200000) . Repeat procedure until scan tool indicates that diagnostic test has run. Repeat for any additional required DTCs that have not run. Using scan tool, observe I/M system status display. If AIR system status updates to YES, go to next step. If AIR system status does not update to yes, see «DIAGNOSTIC AIDS»(ref-117480-S22432811222001091200000) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

AIR pump generally operates once per ignition cycle, usually upon initial start up before engine goes into closed-loop. The active test is performed after engine goes into closed-loop and will only run if passive test fails. The active test may not run if passive test passes.

If diagnostic test does not run, observe fuel trim correction. If fuel trim correction is more than plus or minus 4 percent, the AIR system test may not run. If status does not update, 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 test has passed or failed, only that a decision was made. When all of the 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, the I/M system status will update 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 will indicate MIL is requested. The I/M system status also registers the number of DTCs.

The I/M system status will update only when DTC fails the second time, or all of the tests pass. If there is an impending failure, system may require more time to run the diagnostic than was allotted in the 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 the test does not complete. Some tests may abort due to changes in the conditions while the test is running. For example, changes in engine load such as a cooling fan or an A/C compressor clutch turning on may cause the test to abort.

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

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
2. Turn all accessories off. Start engine and allow to idle. Operate vehicle in the following conditions: 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 brakes applied, A/T in Drive or M/T in Neutral. Using scan tool, monitor I/M System Status display. If catalyst system status updates to YES, go to step 5 . If catalyst system status does not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . 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»(ref-117480-S02034755172001082000000) 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. If catalyst system status is YES, go to next step. If catalyst system status is not YES, see «DIAGNOSTIC AIDS»(ref-117480-S27688567592001091500000) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) .

Purpose of this test is to satisfy enable criteria necessary to execute I/M readiness diagnostics for catalyst system. Test may be used to set I/M system status indicators to YES. Ensure vehicle meets enable criteria before performing test.

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
2. Ensure vehicle is within the conditions for running this test. Turn off all accessories (e.g. A/C, blower fan, etc.). Start and operate engine at idle. In order for this test to run, vehicle must operate in the following conditions: Accelerate at part throttle to 45 MPH and maintain this speed for one minute. Make 4 decelerations of 25 seconds each from 45 MPH with throttle closed, no brake application, no manual downshift, with vehicle speed remaining at more than 25 MPH. After each deceleration period, return vehicle speed to 45 MPH under part throttle acceleration and maintain speed 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 does not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If scan tool does not indicate any other DTCs, go to next step.
4. Using scan tool, observe Not Ran Since Code Cleared display. Determine if DTC P0401, P0404, P0405 or P1404 has not run. Enter DTC number in the Specific DTC menu of scan tool. Operate vehicle within the conditions for running the DTC. Repeat procedure until scan tool indicates that diagnostic test has run. Repeat for any additional DTCs that have not run. Observe I/M System Status display. If EGR system status updates to YES, go to next step. If EGR system status does not update to YES, see «DIAGNOSTIC AIDS»(ref-117480-S12777647982001091200000) .
5. Using scan tool, observe emission related DTC portion of I/M system status display. If scan tool indicates any emission related DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are set, system is okay.

The control module only runs the EGR active tests during a gradual deceleration with a closed throttle and vehicle speed greater than 25 MPH. Several deceleration cycles may be necessary in order to accumulate a sufficient number of EGR flow samples. The procedure outlined is for a clear, flat road. If procedure is performed on a road with a slight downhill grade, test may acquire the necessary sample counters in one or 2 decel trips. If test is interrupted during the procedure, it may take more than 3 deceleration cycles to complete the test. If status does not update, the test 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, DTC portion of the I/M system status display will indicate MIL 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 to complete engine cool down. I/M system status will update only when DTC fails second time, or 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 the 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. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
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 within enable criteria. Turn off all of accessories. Following directions on scan tool, 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 (e.g., failed DTC, test aborted, etc.). Refer to appropriate service information for diagnosis and repair of condition as necessary. After repairs, perform «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) .
5. Ensure vehicle is within enable criteria. Turn off all of accessories. Start and operate engine at idle. Operate vehicle in the following conditions: Accelerate at part throttle to 45 MPH. Maintain this speed until engine reaches operating temperature. This may be up to 8-10 minutes depending on start-up coolant temperature. Continue operating for an additional 3 minutes after engine reaches 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 did not update to YES, go to next step.
6. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . 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 whether DTCs P0440, P0442, P0446 and P1441 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTCs runs. Using scan tool, observe I/M SYSTEM STATUS display. If EVAP SYSTEM STATUS updates to YES, go to next step. If EVAP SYSTEM STATUS does not update to YES, see «DIAGNOSTIC AIDS»(ref-117480-S12814528852001091500000) .
8. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Extreme high or low ambient temperatures may prevent EVAP system tests from initializing. 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, DTC portion of the I/M system status display will indicate MIL 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 to complete engine cool down. I/M system status will update only when DTC fails second time, or 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 the 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. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
2. Turn all accessories off. Start operate engine at idle. Accelerate at part throttle to 45-55 MPH and maintain speed for 6 minutes or until I/M SYSTEM STATUS updates to YES. Vehicles equipped with a 5 or 6-speed manual transmission may require operation in 4th or 5th gear respectively, in order for test to run. Using scan tool, observe I/M SYSTEM STATUS. If HO2S/O2S SYSTEM STATUS updates to YES, go to step 5 . If HO2S/O2S SYSTEM STATUS does not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . 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 whether DTCs P0133, P0140, P1133 and P1134 have run. For those DTCs that have not run, see CODE ENABLE CRITERIA under appropriate DTC under DIAGNOSTIC TESTS. Operate vehicle to meet code enable criteria until DTCs runs. Using scan tool, observe I/M SYSTEM STATUS display. If EVAP SYSTEM STATUS updates to YES, go to next step. If EVAP SYSTEM STATUS does not update to YES, see «DIAGNOSTIC AIDS»(ref-117480-S28967227382001091500000) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) .

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 MIL 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 to complete engine cool down.

I/M SYSTEM STATUS will update only when DTC fails second time, or 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 the 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. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-117480-S37719233642001091200000) . After performing I/M system check, go to next step.
2. Preprogram scan tool with vehicle information before ignition is turned on. Ensure vehicle is within enable criteria. Apply vehicle parking brake. Ensure transmission is in Park (A/T) or Neutral (M/T). Turn off all of accessories. Start and operate engine at 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 does not update to YES, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Using scan tool, monitor DTCs P0135 and P0141. Operate vehicle within code enable criteria for DTCs P0135 and P0141. See «DTC P0135»(ref-117480-S15300504662001082000000) and «DTC P0141»(ref-117480-S29922903682001082000000) 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. If CATALYST SYSTEM STATUS is YES, go to next step. If CATALYST SYSTEM STATUS is not YES, see «DIAGNOSTIC AIDS»(ref-117480-S29046907912001091500000) .
5. Using scan tool, check for DTCs. If any DTCs are set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

HO2S heater tests will normally run within 2 minutes allotted in procedure. If there is an indeterminate condition, test may take up to 8 minutes on some vehicles before a decision of pass or fail is made. 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.

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 MIL 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 to complete engine cool down.

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. DTCs are retrieved using a Tech 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC).

DIAGNOSTIC TROUBLE CODE DEFINITIONS

SCAN TOOL DATA

Typical scan data values table contains all parameters included in the following data lists arranged in alphabetical order

1. Engine Data 1 Contains general information regarding fuel delivery and basic engine operating conditions.
2. Engine Data 2 Contains general information regarding Air Conditioning (A/C), Crankshaft Position (CKP), Camshaft Position (CMP), Knock Sensor (KS), and basic engine operating conditions.
3. Engine Data 3 Contains general information regarding fuel delivery, Engine Coolant Temperature (ECT), Intake Air Temperature (IAT), Vehicle Theft Deterrent (VTD), and basic engine operating conditions.
4. Evaporative Emission (EVAP) Data Contains information specific to Evaporative (EVAP) emissions control system. Also displays parameters required to verify proper EVAP system operation.
5. Fuel Trim Data Contains specific information regarding fuel trim.
6. Misfire Data Contains specific information regarding misfire diagnostics and parameters required to verify proper operation with regard to misfire.

Use typical scan data values only after the following conditions are met

1. Diagnostic system check has been completed.
2. Engine is idling unless checking a value at a specified RPM.
3. Throttle is closed unless checking a value at a specified RPM.
4. Transmission is in Park or Neutral.
5. Vehicle is operating in closed-loop.
6. All accessories are turned off.

DIAGNOSTIC TESTS

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

Note. If PCM is replaced, replacement PCM must be programmed using required or special equipment. See POWERTRAIN CONTROL MODULE under PROGRAMMING.

Note. For component locations, see appropriate SYSTEM & COMPONENT TESTING article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine and allow idle to stabilize for at least one minute. Ensure engine is at normal operating temperature. Using scan tool, monitor oxygen sensor heater. If scan tool reading is 0.25-0.85 amp, problem is intermittent. If scan tool reading is not 0.25-0.85 amp, go to next step.
3. Check fuse for HO2S 1 ignition 1 voltage circuit. Fuse is located in underhood fuse/relay block. If fuse is open, go to step 11. If fuse is okay, go to next step.
4. Turn ignition off. Disconnect HO2S 1 harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe HO2S harness connector terminal "D" (Pink wire). see scheme 2 If test light illuminates, go to next step. If test light does not illuminate, go to step 7.
5. Connect test light between HO2S 1 harness connector terminals "C" (Black/White wire) and "D" (Pink wire). Start engine. If test light illuminates, go to step 9. If test light does not illuminate, go to next step.
6. Turn ignition off. Connect test light between a good ground and HO2S 1 harness connector terminal "C" (Black/White wire). Start engine. If test light illuminates, go to step 8. If test light does not illuminate, go to step 12.
7. Turn ignition off. Repair open in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse/relay block. After repairs, go to step 14.
8. Turn ignition off. Repair short to voltage in Black/White wire between HO2S 1 harness connector "C" and PCM harness connector C2 terminal No. 37. After repairs, go to step 14.
9. Turn ignition off. Check for poor connections or poor terminal tension at HO2S 1 harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to next step.
10. Turn ignition off. Replace HO2S 1. After replacing sensor, go to step 14.
11. Turn ignition off. Locate and repair short to ground in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse/relay block. Replace fuse. After repairs, go to step 14.
12. Turn ignition off. Check for poor connections or poor terminal tension at PCM. Repair as necessary. After repairs, go to step 14. If connection or terminal tension is okay, go to next step.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Start engine and allow idle to stabilize for about one minute. Ensure engine is at normal operating temperature. Using scan tool, monitor oxygen sensor heater current. If scan tool reading is 0.25-0.85 amp, go to next step. If scan tool reading is not 0.25-0.85 amp, go to step 2.
15. Using scan tool, review and record FAILURE RECORDS data. Clear DTCs. Start engine and operate vehicle as close to conditions recorded in FAILURE RECORDS as possible. Monitor SPECIFIC DTC info for this DTC. If scan tool indicates that this DTC failed this ignition, go to step 2. If scan tool does not indicate that this DTC failed this ignition, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine. Using scan tool, monitor DTC information. If any other DTCs are set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no other DTCs are set, go to next step.
3. Observe and record FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S00015572522001091700000). If DTC fails this ignition, go to next step. If DTC did not fail in this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S15302272032001082000000).
4. Operate engine at idle. Ensure engine is at normal operating temperature. Using scan tool, observe MAP sensor voltage parameter. If voltage parameter is 0.8-4.0 volts, go to next step. If voltage parameter is not 0.8-4.0 volts, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
5. Turn ignition off. Check for objects blocking MAF sensor air inlet screen. Check for plugged or collapsed intake air duct or dirty air filter element. Check for vacuum leaks in intake manifold, throttle body, EGR valve flange and pipe, MAF sensor seal, MAP sensor seal, EVAP canister purge valve seal, fuel meter body seal, PCV system, brake booster, and air induction system. Repair as necessary. After repairs, go to step 23. If no problem is found, go to next step.
6. Turn ignition off. Remove vacuum source to MAP sensor. Leave harness connected. Connect a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Using scan tool, observe or record MAP sensor parameter display when vacuum is slowly applied at one in. Hg at a time up to 20 in. Hg. Each one in. Hg applied should result in a 3-4 kPa drop in MAP sensor value on scan tool. Value should change smoothly with each increase in vacuum. If MAP sensor value changes smoothly through the entire range of the test, go to next step. If MAP sensor value does not change smoothly through the entire range of the test, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
7. Apply 20 in. Hg to MAP sensor. If scan tool indicates that MAP sensor reading is 34 kPa or less, go to next step. If MAP sensor reading is not 34 kPa or less, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
8. Disconnect vacuum source from MAP sensor. If MAP sensor reading returns to original value observed in step 6, go to next step. If MAP sensor reading does not return to original value, diagnose MAP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article.
9. Using scan tool, observe TP sensor angle parameter from closed throttle to wide open throttle (0-100 percent) position. If TP sensor value changes smoothly and completely, go to next step. If TP sensor value does not change smoothly, go to «DTC P0121»(ref-117480-S12562949332001082000000).
10. Turn ignition off. Disconnect MAF sensor harness connector. Turn ignition on, with engine off. Check voltage between ground and MAF sensor harness connector terminal "A" (Yellow wire). see scheme 3 If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 12.
11. Connect test light between MAF sensor harness connector terminals "B" (Black/White wire) and C" (Pink wire). If test light illuminates, go to step 19. If test light does not illuminate, go to step 14.
12. If voltage reading is less than 4.5 volts, go to step 15. If voltage reading is not less than 4.5 volts, go to next step.
13. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Check voltage between ground and MAF sensor harness connector terminal "A" (Yellow wire). If voltage reading is about zero volts, go to step 22. If voltage reading is not about zero volts, go to step 18.
14. Connect test light between ground and MAF sensor harness connector terminal "C" (Pink wire). If test light illuminates, go to step 16. If test light does not illuminate, go to step 17.
15. Turn ignition off. Disconnect PCM harness connector. Check Yellow wire between PCM harness connector C1 terminal No. 69 and MAF sensor harness connector terminal "A" for high resistance, open circuit, or short to ground. see scheme 3and see scheme 4. Repair as necessary. After repairs, go to step 23. If circuit is okay, go to step 20.
16. Turn ignition off. Repair high resistance or open in Black/White wire. After repairs, go to step 23.
17. Turn ignition off. Repair short to ground or open in Pink wire. Replace fuse if necessary. After repairs, go to step 23. If circuit is okay, go to step 21.
18. Turn ignition off. Repair short to voltage in Yellow wire. After repairs, go to step 23.
19. Turn ignition off. Check for poor connections at MAF sensor harness connector. Repair as necessary. After repairs, go to step 23. If connections are okay, go to step 21.
20. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 23. If connections are okay, go to step 22.
21. Replace MAF sensor. After replacing sensor, go to step 23.
22. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
23. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S00015572522001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
24. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for sticking throttle plate. Check for carbon build-up on throttle plate and throttle bore. Check TP sensor. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. Check for poor connection at PCM. Check for misrouted or damaged MAF sensor wiring harness. Ensure harness is not close to high-voltage components.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine. Using scan tool, observe MAF sensor frequency parameter. If MAF sensor frequency parameter is 1200 Hz, go to step 4. If MAF sensor frequency parameter is not 1200 Hz, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle as close to conditions recorded in FREEZE FRAME as possible. Select SPECIFIC DTC function, then enter this DTC. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S17405508052001082000000).
4. Turn ignition off. Check fuse in ignition 1 voltage circuit of MAF sensor. Fuse is located in underhood fuse/relay block. If fuse is open, go to step 14. If fuse is okay, go to next step.
5. Disconnect MAF sensor harness connector. Turn ignition on, with engine off. Check voltage between chassis ground and MAF sensor harness connector terminal "A" (Yellow wire). see scheme 3 If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 8.
6. Turn ignition off. Connect a fused jumper wire between ground and MAF harness connector terminal "A" (Yellow wire). Start engine. Recheck for DTCs. If any additional DTCs are set, go to step 16. If no additional DTCs are set, go to next step.
7. Turn ignition off. Connect a test light between MAF sensor harness connector terminal "C" (Pink wire) and ground circuit. Turn ignition on, with engine off. If test light illuminates, go to step 18. If test light does not illuminate, go to step 11.
8. If voltage reading is less 4.5 volts, go to step 10. If voltage reading is not less than 4.5 volts, go to next step.
9. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Check voltage between ground and MAF sensor harness connector terminal "A" (Yellow wire). If voltage reading is zero volts, go to step 12. If voltage reading is not zero volts, go to step 15.
10. Turn ignition off. Disconnect PCM harness connector. Check for high resistance, open circuit, short to ground, or short to ground circuit on Yellow wire between MAF sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 69. Repair as necessary. After repairs, go to step 22. If circuit is okay, go to step 12.
11. Connect a test light between MAF sensor harness connector terminal "C"(Pink wire) and a known-good ground. If test light illuminates, go to step 13. If test light does not illuminate, go to step 14.
12. Turn ignition off. Using a DVOM, check for continuity of Yellow wire between MAF sensor and PCM harness connectors. If continuity exists, go to step 17. If continuity does not exist, go to step 19.
13. Turn ignition off. Repair high resistance or open in Black/White wire between MAF sensor harness connector terminal "B" and ground connector. After repairs, go to step 22.
14. Turn ignition off. Check for short to ground or an open in Pink wire between MAF sensor harness connector terminal "C and underhood fuse/relay block. Repair as necessary. Replace fuse, if open. After repairs, go to step 22. If circuit is okay, go to step 20.
15. Turn ignition off. Repair short to voltage in Yellow wire between MAF sensor and PCM harness connectors. After repairs, go to step 22.
16. Turn ignition off. Repair short between MAF sensor signal circuit (Yellow wire) and circuit for which the DTC set. After repairs, go to step 22.
17. Repair circuits that are shorted together. After repairs, go to step 22.
18. Turn ignition off. Check for poor connections at MAF sensor harness connector. Repair as necessary. After repairs, go to step 22. If connections are okay, go to step 20.
19. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 22. If connections are okay, go to step 21.
20. Replace MAF sensor. After replacing sensor, go to step 22.
21. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repairs, go to next step.
22. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S31407077432001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
23. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are present, system is okay.

Check for poor connection at PCM. Check for misrouted MAF sensor wiring harness. Ensure harness is not close to high voltage components. Check for damaged wiring harness. Check for plugged intake air duct or filter element.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S18256951752001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S14394297082001082000000) .
3. Turn ignition off. Disconnect MAF sensor harness connector. Start engine. Using scan tool, observe frequency parameter of MAF sensor. If scan tool displays zero Hz, go to step 5 . If scan tool does not display zero Hz, go to next step.
4. Turn ignition off. Check MAF sensor harness for incorrect routing at secondary ignition wires or coils, solenoids, relays or motors. Repair as necessary. After repairs, go to step 9 . If no problem is found, go to next step.
5. Turn ignition off. Check for poor connections at MAF sensor harness connector. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to step 7 .
6. Check PCM harness connector for poor connections. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to step 8 .
7. Replace MAF sensor. After replacing sensor, go to step 9 .
8. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repairs, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S18256951752001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
10. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine. Check for DTCs. If DTC P1635 is current, go to «DTC P1635»(ref-117480-S12566097162001082000000). If DTC P1635 is not current, go to next step.
3. Using scan tool, observe MAP sensor voltage. If voltage reading is less than 0.1 volt, go to step 5. If voltage reading is not less than 0.1 volt, go to next step.
4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S34817565262001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S20564060812001082000000).
5. Turn ignition off. Disconnect MAP sensor harness connector. Connect a DVOM between MAP sensor harness connector terminal "C" (Gray wire) and a good ground. see scheme 5 Turn ignition on, with engine off. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 7.
6. Connect a fused jumper wire between MAP sensor harness connector terminals "B" (Light Green wire) and "C" (Gray wire). If scan tool indicates that voltage is about 5 volts, go to step 9. If voltage reading is not about 5 volts, go to step 8.
7. Turn ignition off. Check for short to ground or open circuit in Gray wire between MAP sensor harness connector terminal "C" and PCM harness connector C1 terminal No. 10. see scheme 4 Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 10.
8. Turn ignition off. Check for short to ground or open circuit in Light Green wire between MAP sensor harness connector "B" and PCM harness connector C2 terminal No. 25. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 10.
9. Turn ignition off. Check for poor connections at MAP sensor harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to step 11.
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to step 12.
11. Replace MAP sensor. After replacing sensor, go to step 13.
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repairs, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S34817565262001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine. If scan tool indicates that DTC P1635 is current, go to «DTC P1635»(ref-117480-S12566097162001082000000). If DTC P1635 is not current, go to next step.
3. If engine idle is rough, unstable or incorrect, repair idle condition before proceeding with test. If idle quality is okay, allow engine to idle. Observe scan tool. If scan tool indicates that MAP sensor voltage is greater than 4.3 volts, go to step 5. If MAP sensor voltage is not greater than 4.3 volts, go to next step.
4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S04093304862001091700000). If DTC fails this ignition, go to next step. If DTC does not fail in this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S09479384272001082000000).
5. Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on, with engine off. If scan tool indicates that MAP sensor voltage is less than 0.1 volt, go to next step. If MAP sensor voltage is not less than 0.1 volt, go to step 8.
6. Disconnect ECT harness connector. Connect a DVOM between MAP sensor harness connector terminals "A" (Orange/Black wire) and "C" (Gray wire). see scheme 5 If voltage reading is 4.7-5.2 volts, go to step 11. If voltage reading is not 4.7-5.2 volts, go to next step.
7. If voltage reading is greater than 5.2 volts, go to step 10. If voltage reading is not greater than 5.2 volts, go to step 9.
8. Turn ignition off. Check for short to voltage in Light Green wire between MAP sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 25. Repair as necessary. After repairs, go to step 15. If circuit is okay, go to step 12.
9. Turn ignition off. Check for open in Orange/Black wire between MAP sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 13. Repair as necessary. After repairs, go to step 15. If circuit is okay, go to step 12.
10. Turn ignition off. Check for short to voltage in Gray wire between MAP sensor harness connector terminal "C" and PCM harness connector C1 terminal No. 10. Repair as necessary. After repairs, go to step 15. If circuit is okay, go to step 12.
11. Turn ignition off. Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 15. If connections are okay, go to step 13.
12. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 15. If connections are okay, go to step 14.
13. Replace MAP sensor. After replacing sensor, go to step 15.
14. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
15. Turn ignition on, with engine off. Use scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S04093304862001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
16. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe MAP display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe IAT parameter. If IAT parameter is greater than 275°F (135°C), go to step 4. If IAT parameter is not greater than 275°F (135°C), go to next step.
3. Using scan tool, review and record the FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions. If this DTC failed this ignition, go to next step. If this DTC did not fail in this ignition, problem is intermittent.
4. Turn ignition off. Disconnect IAT sensor. Turn ignition on, with engine off. Using scan tool, observe IAT parameter. If IAT parameter is less than -35°F (-37°C), go to step 6. If IAT parameter is not less than -35°F (-37°C), go to next step.
5. Turn ignition off. Check for short to ground in Tan wire between IAT sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 50. see scheme 4 Repair as necessary. After repairs, go to step 8. If circuit is okay, go to step 7.
6. Replace IAT sensor. After replacing sensor, go to step 8.
7. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repairs, go to next step.
8. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S13817222372001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, observe IAT parameter. If IAT parameter is less than -35°F (-37°C), go to step 4. If IAT parameter is not less than -35°F (-37°C), go to next step.
3. Turn ignition on, engine off. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S32251136462001082000000).
4. Turn ignition off. Disconnect IAT sensor harness connector. Connect a fused jumper wire between IAT sensor harness connector terminals. Turn ignition on, with engine off. Using scan tool, observe IAT parameter. If IAT parameter is greater than 275°F (135°C), go to step 6. If IAT parameter is not greater than 275°F (135°C), go to next step.
5. Connect jumper wire between chassis ground and IAT sensor harness connector "B" (Tan wire). Using scan tool, observe IAT parameter. If IAT parameter is greater than 275°F (135°C), go to step 7. If IAT parameter is not greater than 275°F (135°C), go to step 8.
6. Turn ignition off. Check for short to voltage in Tan wire between IAT sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 50. see scheme 4 Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 10.
7. Check for high resistance or open circuit in Black wire between IAT harness connector terminal "A" and PCM harness connector C1 terminal No. 17. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 9.
8. Turn ignition off. Check for open in Tan wire between IAT sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 50. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to next step.
9. Check for faulty connection at PCM harness connector C1 terminal No. 17 (Black wire) or PCM harness connector C2 terminal No. 50 (Tan wire). Repair as necessary. After repairs, go to step 13. If connections are okay, go to step 12.
10. Check for faulty connections at IAT sensor harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to next step.
11. Replace IAT sensor. After replacing sensor, go to step 13.
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S22435533172001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe IAT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Check coolant level. Add coolant as necessary or repair cause of coolant loss. After repairs or if coolant level is okay, go to next step.
3. Turn ignition off. Disconnect ECT harness connector (located near coolant outlet). Connect a fused (3-amp) jumper wire between ECT sensor harness connector terminals. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If scan tool indicates that ECT sensor temperature is greater than 280°F (138°C), go to next step. If scan tool does not indicate that ECT sensor temperature is greater than 280°F (138°C), go to step 5 .
4. Turn ignition off. Disconnect IAT sensor harness connector (located in air inlet tube). Connect a fused jumper wire between IAT sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe IAT sensor temperature. If scan tool indicates that IAT sensor temperature is greater than 280°F (138°C), go to step 8 . If scan tool does not indicate that IAT sensor temperature is greater than 280°F (138°C), see «DIAGNOSTIC AIDS»(ref-117480-S39906447452001111000000) .
5. Turn ignition off. Disconnect ECT sensor harness connector. Connect a fused jumper wire between a known-good ground and ECT sensor harness connector terminal "B" (Yellow wire). Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If scan tool indicates that ECT sensor temperature is greater than 280°F (138°C), go to next step. If scan tool does not indicate that ECT sensor temperature is greater than 280°F (138°C), go to step 7 .
6. Turn ignition off. Check for high resistance or open in Orange/Black wire between ECT sensor and PCM. Repair as necessary. After repairs, go to step 11 .
7. Turn ignition off. Check for high resistance or open in Yellow wire between ECT sensor and PCM. Repair as necessary. After repairs, go to step 11 .
8. Turn ignition off. Remove ECT sensor. Suspend ECT sensor and a thermometer in a pan of water. Place pan on a burner or hot plate. Check resistance of ECT sensor through the specified range of temperatures. See TEMPERATURE VS RESISTANCE table in SENSOR OPERATING RANGE CHARTS article. If resistance and temperature closely matches the TEMPERATURE VS RESISTANCE table, go to next step. If resistance and temperature does not closely match the TEMPERATURE VS RESISTANCE, go to step 10 .
9. Reinstall ECT sensor. After reinstalling sensor, see «DIAGNOSTIC AIDS»(ref-117480-S39906447452001111000000) .
10. Replace ECT sensor. After replacing sensor, go to next step.
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S18790735622001111000000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
12. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

DTC P0116 is designed to detect an ECT sensor that is skewed high or an IAT sensor that is skewed low. When checking ECT sensor, the Temperature vs Resistance table should be used in order to determine if a skewed sensor is the problem. If engine has been allowed to sit overnight, the ECT and IAT temperature should be within the calculated amount.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe ECT parameter. If ECT parameter is greater than 282°F (139°C), go to step 4. If ECT temperature is not greater than 282°F (139°C), go to next step.
3. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S42267482742001082000000).
4. Turn ignition off. Disconnect ECT sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe ECT parameter. If ECT parameter is less than -36°F (-38°C), go to step 6. If ECT parameter is not less than -36°F (-38°C), go to next step.
5. Turn ignition off. Check for short to ground or short to sensor ground circuit in Orange/Black wire between ECT sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 13. see scheme 4 Repair as necessary. After repairs, go to step 8. If circuit is okay, go to step 7.
6. Turn ignition off. Replace ECT sensor. After replacing sensor, go to step 8.
7. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
8. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S06532256122001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe ECT parameter. If ECT parameter is less than -36°F (-38°C), go to step 4. If ECT parameter is not less than -36°F (-38°C), go to next step.
3. Using scan tool, read and record FAILURE RECORDS data. Operate vehicle within conditions noted in FAILURE RECORDS data. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S37093137862001082000000).
4. Turn ignition off. Disconnect ECT sensor harness connector. Connect a fused jumper wire between ECT sensor harness connector terminals. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature is greater than 280°F (138°C), go to step 8. If ECT sensor temperature is not greater than 280°F (138°C), go to next step.
5. Connect fused jumper wire between a known-good ground and ECT sensor harness connector terminal "B" (Yellow wire). Using scan tool, observe ECT parameter. If ECT parameter is greater than 280°F (138°C), go to step 7. If ECT parameter is not greater than 280°F (138°C), go to next step.
6. Turn ignition off. Check for short to voltage, high resistance or open in Yellow wire between ECT sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 26. see scheme 4 Repair as necessary. After repairs, go to step 12. If circuit is okay, go to next step.
7. Turn ignition off. Check for high resistance or open in Orange/Black wire between ECT harness connector terminal "B" and PCM harness connector C1 terminal No. 13. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 9.
8. Turn ignition off. Check for poor connections at ECT sensor harness connector. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 10.
9. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 11.
10. Replace ECT sensor. After replacing sensor, go to step 12.
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
12. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S40442221642001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe ECT display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, check for DTCs. If any other DTCs are set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no other DTCs are set, observe TP sensor angle parameter on scan tool while slowly opening throttle from closed position to Wide Open Throttle (WOT) position. If TP angle value increases steadily and evenly from zero (closed) to 98 percent (WOT), go to next step. If TP sensor angle value does not increase steadily and evenly from zero (closed) to 98 percent (WOT), go to step 4.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S29959434502001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S19866794272001082000000).
4. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If TP sensor voltage parameter is zero volts, go to next step. If TP sensor voltage parameter is not zero volts, go to step 6.
5. Turn ignition off. Connect fused jumper wire between TP sensor harness connector terminals "A" (Gray wire) and "C" (Dark Blue wire). Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If TP sensor voltage parameter is 5 volts, go to step 9. If TP sensor voltage parameter is not 5 volts, go to step 7.
6. Turn ignition off. Check for short to voltage in Dark Blue wire between TP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 66. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 12.
7. Turn ignition off. Check for open or high resistance in Gray wire between TP sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 33. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to next step.
8. Check for open or high resistance in Dark Blue wire between TP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 66. see scheme 4 Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 11.
9. Turn ignition off. Check for open or high resistance in Black wire between TP sensor harness connector terminal "B" and PCM harness connector C1 terminal No. 61. see scheme 4 Repair as necessary. After repairs, go to step 14. If circuit is okay, go to next step.
10. Check for poor connection at TP sensor harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 12.
11. Check PCM harness connector for poor connection. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 13.
12. Replace TP sensor. After replacing sensor, go to step 14.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S29959434502001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for damaged or sticking throttle plate or IAC valve. A throttle valve plate or IAC valve that allows too much airflow while throttle should be closed may cause a high idle and DTC P0121 to set.

A skewed MAP signal or faulty MAP sensor or an incorrect MAP signal may cause PCM to incorrectly calculate the predicted TP sensor value during high engine load situations. Check for an unusually low MAP reading. This condition can cause DTC to set.

Check for poor connections at PCM. Check harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe TP voltage parameter. If TP sensor voltage is less than 0.1 volt, go to step 4. If TP sensor voltage is not less than 0.1 volt, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S17019024022001091700000). If DTC fails this ignition, go to next step. If DTC did not fail in this ignition, go to «DTC P1121»(ref-117480-S34688265602001082000000).
4. Turn ignition off. Disconnect TP sensor harness connector. Connect a fused jumper wire between TP sensor harness connector terminals "A" (Gray wire) and "C" (Dark Blue wire). see scheme 6 Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If TP sensor voltage is 5 volts, go to step 11. If TP sensor voltage is not 5 volts, go to next step.
5. Disconnect fused jumper wire. Check voltage between TP sensor harness connector terminals "A" (Gray wire) and "B" (Black wire). If voltage reading is about 5 volts, go to step 9. If voltage reading is not about 5 volts, go to next step.
6. Turn ignition off. Check for open or high resistance in Gray wire between TP sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 33. see scheme 4 Repair as necessary. After repairs, go to step 14. If circuit is okay, go to next step.
7. Check for short to ground in Gray wire between TP sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 33. Repair as necessary. After repairs, go to step 14. If circuits are okay, go to next step.
8. Turn ignition on. Connect DVOM between TP sensor harness connector terminals "A" (Gray wire) and "B" (Black wire). Observe voltage while disconnecting all sensors using a 5-volt reference signal, one at a time. See WIRING DIAGRAMS article. A change in voltage indicates a faulty component. Turn ignition off. Replace affected component(s) as necessary. After repairs, go to step 14. If no problem is found, go to step 10.
9. Turn ignition off. Check for open, high resistance, or for short to ground in Dark Blue wire between TP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 66. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to next step.
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 13.
11. Turn ignition off. Check for poor connection at TP sensor harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to next step.
12. Replace TP sensor. After replacing sensor, go to step 14.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S17019024022001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter with throttle closed. If TP sensor voltage is greater than 4.9 volts, go to step 4. If TP sensor voltage is not greater than 4.9 volts, go to next step.
3. Using scan tool, observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS observed. See «CODE ENABLE CRITERIA»(ref-117480-S15177981562001091700000). If DTC fails this ignition, go to next step. If DTC did not fail this ignition, go to «DTC P1121»(ref-117480-S34688265602001082000000).
4. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage parameter. If TP voltage is zero volts, go to next step. If TP voltage is not zero volts, go to step 8.
5. Using DVOM, check voltage between ground and TP sensor harness connector terminal "A" (Gray wire). see scheme 6 If TP voltage parameter is 5 volts, go to next step. If TP voltage parameter is not 5 volts, go to step 9.
6. Connect a test light between battery voltage and TP sensor harness connector terminal "B" (Black wire). If test light illuminates, go to step 10. If test light does not illuminate, go to next step.
7. Check for high resistance or open in Black wire between TP sensor harness connector terminal "B" and PCM harness connector C1 terminal No. 61. Repair as necessary. After repairs, go to step 18. If circuit is okay, go to step 15.
8. Turn ignition off. Check for short to voltage in Dark Blue wire between TP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 66. Repair as necessary. After repairs, go to step 18. If circuit is okay, go to step 15.
9. Turn ignition off. Check all 5-volt reference circuits for short to voltage. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 18. If circuit is okay, go to next step.
10. Connect DVOM between TP sensor harness connector terminals "A" (Gray wire) and "B" (Black wire). Turn ignition on. Using scan tool, command EGR valve to 100 percent while observing DVOM. If voltage changes while commanding EGR, go to next step. If voltage does not change while commanding EGR, go to step 14.
11. Disconnect EGR valve harness connector. With DVOM still connected to TP sensor, observe voltage while commanding EGR to 100 percent. If voltage changes while commanding EGR, go to step 13. If voltage does not change while commanding the EGR, go to next step.
12. Turn ignition off. Replace EGR valve. After replacing EGR valve, go to step 17.
13. Turn ignition off. Repair short between EGR harness connector terminals "A" (Red wire) and D" (Gray wire). see scheme 9 After repairs, go to step 18.
14. Turn ignition off. Check for poor connections at TP sensor harness connector. Repair as necessary. After repairs, go to step 18. If connections are okay, go to step 16.
15. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 18. If connections are okay, go to step 17.
16. Replace TP sensor. After replacing sensor, go to step 18.
17. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
18. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S15177981562001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
19. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe TP sensor display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Check if any ECT related DTCs are set. Diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no ECT related DTCs are set, go to next step.
3. Turn ignition off. Disconnect ECT sensor harness connector. Connect a fused jumper wire between ECT sensor harness connector terminals. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature is greater than 280°F (138°C), go to step 7 . If ECT sensor temperature is not greater than 280°F (138°C), go to next step.
4. Turn ignition off. Connect jumper wire between ECT sensor harness connector terminal "B" (Yellow wire) and a known-good ground. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature is greater than 280°F (138°C), go to next step. If ECT sensor temperature is not greater than 280°F (138°C), go to step 6 .
5. Turn ignition off. Repair high resistance or open in Orange/Black wire between ECT sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 13. After repairs, go to step 10 .
6. Turn ignition off. Repair high resistance or open in Orange/Black wire between ECT sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 13. After repairs, go to step 10 .
7. Turn ignition off. Remove ECT sensor. Suspend ECT sensor and a thermometer in a pan of water. Place the pan on a burner or hot plate. Check resistance of ECT sensor through the specified range of temperatures. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. If resistance and temperature closely matches the specified range, go to next step. If resistance does not match the specified range, go to step 9 .
8. Reinstall ECT sensor. Diagnose and repair engine cooling system problem.
9. Replace ECT sensor. After replacing sensor, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S23753695562001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check coolant level. Ensure thermostat and cooling fans are operating properly. Check for high resistance in wiring related to ECT sensor. Check for skewed ECT sensor by comparing actual coolant temperature with scan tool display, and replace ECT sensor if temperatures are not close.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Check coolant level. If coolant level is low, diagnose and repair cause of coolant loss. If coolant level is okay, go to next step.
3. Turn ignition off. Disconnect ECT sensor harness connector. Connect a fused jumper wire between ECT sensor harness connector terminals. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature is greater than 280°F (138°C), go to step 7. If ECT sensor temperature is not greater than 280°F (138°C), go to next step.
4. Turn ignition off. Connect jumper wire between ECT sensor harness connector terminal "B" (Yellow wire) and a known-good ground. Turn ignition on, with engine off. Using scan tool, observe ECT sensor temperature. If ECT sensor temperature is greater than 280°F (138°C), go to next step. If ECT temperature is not greater than 280°F (138°C), go to step 6.
5. Repair high resistance or open circuit in Orange/Black wire between ECT harness connector terminal "A" and PCM harness connector C1 terminal No. 13. see scheme 4 After repairs, go to step 10.
6. Turn ignition off. Repair high resistance or open in Yellow wire between ECT harness connector terminal "B" and PCM harness connector C2 terminal No. 26. After repairs, go to step 10.
7. Turn ignition off. Remove ECT sensor. Suspend ECT sensor and thermometer in a pan of water. Place pan on a burner or hot plate. Check ECT sensor resistance through the specified range of temperatures. See ENGINE SENSORS & SWITCHES in appropriate SYSTEM & COMPONENT TESTING article. If resistance and temperature closely matches the specified range, go to next step. If resistance and temperature does not closely match the specified range, go to step 9.
8. Reinstall ECT sensor. Diagnose and repair engine cooling system.
9. Replace ECT sensor. After replacing sensor, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S07845821412001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
11. Using scan tool, observe stored information and CAPTURED INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

This DTC is designed to detect a faulty thermostat. It is possible for a skewed ECT sensor to cause this DTC to set. If DTCs P0125 and P0128 are both set, a skewed ECT sensor is the most likely cause. A skewed Intake Air Temperature (IAT) sensor may cause this DTC to set. IAT sensor should read about ambient temperature with engine running.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, clear DTCs and reset fuel trim values. Warm engine to normal operating temperature. Operate engine at idle. Using scan tool, observe HO2S 1 voltage. If HO2S 1 voltage is 300-600 millivolts, go to step 4. If HO2S 1 voltage is not 300-600 millivolts, go to next step.
3. The condition that set this DTC is not present. This DTC may have been set by water intrusion in connector, intermittently open HO2S 1 high signal or low reference circuits, HO2S 1 low reference circuit with high resistance to ground, PCM ground circuits with high resistance to ground, inoperative HO2S 1 heater, poor HO2S or PCM connector terminal contact, exhaust leak within 12 inches upstream of HO2S 1, or a defective HO2S 1. Repair as necessary. After repairs, go to step 17. If no problem is found, problem is intermittent.
4. Turn ignition off. Disconnect HO2S 1 harness connector. Jumper HO2S 1 harness connector terminal "A" (Tan wire) to a known-good ground. see scheme 2 Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If voltage measures less than 20 millivolts, go to step 7. If HO2S voltage does not measure less than 20 millivolts, go to next step.
5. Turn ignition off. Remove jumper wire from HO2S harness connector. Disconnect PCM harness connectors C1 and C2. Using DVOM, check resistance of Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10. Check resistance of Tan wire between HO2S 1 harness connector terminal "A" and PCM harness connector C1 terminal No. 12. see scheme 4 If resistance on each circuit is less than 5 ohms, go to next step. If resistance on either circuit is not less than 5 ohms, go to step 9.
6. Check for proper PCM connector terminal contact. Repair PCM terminals as necessary. After repairs, go to step 17. If terminal contact is okay, go to step 16.
7. Remove jumper wire from HO2S harness connector. Connect a test light between HO2S 1 harness connector terminals "C" (Black wire) and "D" (Pink wire). Start engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10.
8. Turn ignition off. Reconnect HO2S 1 harness connector. Disconnect PCM harness connectors. Using DVOM, check resistance between PCM harness connector C1 terminal No. 12 (Tan wire) and one of PCM ground circuit terminals (terminals No. 16, 56, 57 or 60). See WIRING DIAGRAMS article. If resistance is less than 500 ohms, go to step 12. If resistance is not less than 500 ohms, go to step 11.
9. Repair circuit with high resistance. After repairs, go to step 17.
10. Turn ignition off. Repair Pink or Black/White wires to HO2S 1. After repairs, go to step 17.
11. Repair high resistance in Tan wire between HO2S 1 harness connector "A" and PCM harness connector C1 terminal No. 12. Repair PCM ground circuit (terminals No. 16, 56, 57 or 60). After repairs, go to step 17.
12. Start engine. Check exhaust system for leaks, upstream of suspect HO2S. Leak may be very small and will typically be within 12 inches of suspect HO2S. Turn ignition off. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
13. Turn ignition off. Allow engine to cool to ambient temperature. Using DVOM, recheck resistance between HO2S l low reference circuit (Tan wire) and PCM ground circuit terminal. If resistance is less than 500 ohms, go to step 15. If resistance is not less than 500 ohms, go to next step.
14. Remove HO2S 1. Clean HO2S mounting threads. Apply anti-seize compound to sensor threads. Tighten HO2S to proper torque. Recheck resistance between HO2S low reference circuit (Tan wire) and PCM ground circuit terminal. If resistance less than 500 ohms, go to step 17. If resistance is not less than 500 ohms, go to next step.
15. Replace HO2S 1 sensor. After replacing sensor, go to step 17.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S41797073012001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using scan tool, observe stored information and CAPTURE INFO. If any undiagnosed DTCs are displayed, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. If connections and harnesses appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Warm engine to normal operating temperature. Using scan tool, observe HO2S voltage for the sensor that applies to this DTC. If HO2S voltage is less than 175 millivolts, go to step 4. If HO2S voltage is not less than 175 millivolts, go to next step.
3. The condition that set this DTC is not present. This DTC may have been set by a signal wire intermittently shorted to engine ground or to HO2S low reference circuit, HO2S connector water intrusion, exhaust leak between HO2S and engine. DTC may also be set by an intermittent lean engine condition resulting from vacuum leaks, incorrect or defective PCV valve or system, incorrect fuel pressure, lean fuel injectors, inaccurate MAF sensor, or lean engine condition during power enrichment operation. Repair as necessary. After repairs, go to step 10. If no problem is found, problem is intermittent.
4. Turn ignition off. Disconnect HO2S 1 harness connector. Using a jumper wire, jumper HO2S 1 harness connector terminal "A" (Tan wire) to a known-good ground. see scheme 2 Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If voltage reading is 351-551 millivolts, go to next step. If voltage reading is not 351-551 millivolts, go to step 6.
5. Turn ignition off. Check for HO2S connector water intrusion, exhaust leak between HO2S and engine, vacuum leaks, incorrect or defective PCV valve or system, incorrect fuel pressure, lean fuel injectors, or inaccurate MAF sensor. Repair as necessary. After repairs, go to step 10. If no problem is found, go to step 8.
6. Turn ignition off. Remove jumper wire from HO2S 1 harness connector terminal "A" (Tan wire). Disconnect PCM harness connectors C1 and C2. Using DVOM, measure and record resistance between HO2S harness connector terminal "B" (Purple wire) chassis ground. Measure and record resistance between HO2S harness connector terminals "A" (Tan wire) and "B" (Purple wire). If resistance is infinite on both tests, go to step 9. If resistance is not infinite on either test, go to next step.
7. Repair Purple wire circuit for short to ground or short to Tan wire. After repairs, go to step 10.
8. Replace HO2S 1. After replacing sensor, go to step 10.
9. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn igniting off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S30052062542001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
11. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check HO2S pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. Check for fuel contamination, improper fuel pressure or exhaust leak, especially near oxygen sensor. Check for vacuum or crankcase leak, causing a lean condition. Check MAF sensor.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Warm engine to normal operating temperature. Using scan tool, observe HO2S 1 voltage. If voltage reading is less than 975 millivolts, go to next step. If voltage reading is not less than 975 millivolts, go to step 4.
3. The condition that set this DTC is not present. This DTC may have been set by an HO2S high signal wire intermittently shorted to engine ground, HO2S low reference circuit connector water intrusion, or silicone contamination of HO2S. DTC may also have been set by an intermittently rich engine condition caused by EVAP canister purge system malfunction, fuel contamination of engine oil, incorrect fuel pressure, leaking fuel pressure regulator, rich fuel injectors, inaccurate MAF sensor, rich engine condition during Deceleration Fuel Cut-Off (DFCO) operation. Repair as necessary. After repairs, go to step 10. If no problem is found, see «DIAGNOSTIC AIDS»(ref-117480-S32982472332001082000000).
4. Turn ignition off. Disconnect HO2S 1 harness connector. Using a jumper wire, jumper HO2S 1 harness connector terminal "A" (Tan wire) to a known-good ground. see scheme 2 Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If voltage reading is 351-551 millivolts, go to next step. If voltage reading is not 351-551 millivolts, go to step 6.
5. The HO2S is detecting a rich exhaust condition or may be contaminated. Check for water intrusion in HO2S connector, silicone contamination of HO2S, fuel contamination in engine oil, EVAP canister purge system malfunction, incorrect fuel pressure, rich fuel injectors, inaccurate MAF sensor. Repair as necessary. After repairs, go to step 10. If no problem is found, go to step 8.
6. Turn ignition off. Remove jumper from HO2S 1 harness connector terminal "A". Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, check voltage between PCM harness connector C2 terminal No. 10 (Purple wire) and chassis ground. If voltage reading is greater than 20 millivolts, go to next step. If voltage reading is not greater than 20 millivolts, go to step 9.
7. Turn ignition off. Repair short to voltage in Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10. After repairs, go to step 10.
8. Determine and repair cause of HO2S contamination. Replace HO2S 1. After repairs, go to step 10.
9. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
10. If a rich engine condition was repaired, inspect engine oil for fuel contamination. Replace engine oil as necessary. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S16943223582001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
11. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check fuel pressure. Perform injector balance test. See FUEL SYSTEM (GASOLINE) in appropriate SYSTEM & COMPONENT TESTING article. Check for leaking fuel pressure regulator by removing vacuum hose and checking for fuel presence. If fuel is present, replace regulator. Check EVAP canister for fuel saturation. Check MAF sensor.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If any DTCs are set, except P1134, refer to affected DTCs before proceeding with this test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . With engine at normal temperature, operate vehicle within conditions for running DTC. Using scan tool, monitor SPECIFIC DTC INFORMATION for this DTC until the test runs. If DTC failed, go to next step. If DTC did not fail, problem is intermittent.
3. If scan tool also indicates that DTC P1134 also failed the last test, go to step 6 . If scan tool does not indicate that DTC P1134 failed the last test, go to next step.
4. Check for properly installed and secure HO2S 1. Check sensor for corrosion on terminals, damaged wiring, or poor connections at sensor and at PCM. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to next step.
5. Check for exhaust leak, proper HO2S installation, or damaged HO2S wiring. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to next step.
6. Ensure source of HO2S contamination is repaired before replacing sensor. Replace HO2S Bank 1, Sensor 1. After replacing sensor, go to next step.
7. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S33499238712001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe HO2S 1 display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, clear DTCs and reset fuel trim values. Warm engine to normal operating temperature. Observe HO2S 1 voltage. If voltage reading is 408-512 millivolts, go to step 4. If voltage reading is not 408-512 millivolts, go to next step.
3. The condition that set this DTC is not present. This DTC may have been set by HO2S connector water intrusion, intermittently open HO2S circuits, HO2S circuits with high resistance to ground, PCM ground circuits with high resistance to ground, inoperative HO2S heater, poor HO2S or PCM connector terminal contact, exhaust system leak within 12 inches upstream of HO2S, or faulty HO2S. Repair as necessary. After repairs, go to step 17. If no problem is found, problem is intermittent.
4. Turn ignition off. Disconnect HO2S 1 harness connector. Using a jumper wire, jumper HO2S 1 harness connector terminals "A" (Tan wire) and "B" (Purple wire) to a known-good ground. see scheme 2 Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If HO2S voltage is less than 20 millivolts, go to step 7. If HO2S voltage is not less than 20 millivolts, go to next step.
5. Turn ignition off. Remove jumper wires from HO2S harness connector terminals. Disconnect PCM harness connectors C1 and C2. Using a DVOM, check resistance of Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10. Check resistance of Tan wire between HO2S 1 harness connector terminal "A" and PCM harness connector C1 terminal No. 12. If each resistance is less than 5 ohms, go to next step. If each resistance is not less than 5 ohms, go to step 9.
6. Check for proper PCM harness connector terminal contact. Repair as necessary. After repairs, go to step 17. If terminal contact is okay, go to step 16.
7. Remove jumper wires from HO2S 1 harness connector terminals. Connect a test light between HO2S 1 harness connector terminals "A" (Tan wire) and "D" (Pink wire). Start engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10.
8. Turn ignition off. Reconnect HO2S harness connector. Disconnect PCM harness connectors. Using DVOM, check resistance between HO2S 1 harness connector terminal "A" (Tan wire) and one of the PCM ground circuit terminals (PCM terminals No. 16, 56 or 57). See WIRING DIAGRAMS. If resistance is less than 500 ohms, go to step 12. If resistance is not less than 500 ohms, go to step 11.
9. Repair circuit with high resistance. After repairs, go to step 17.
10. Turn ignition off. Repair open, high resistance or poor ground connection in HO2S 1 power circuit. Replace fuse if necessary. After repairs, go to step 17.
11. Repair high resistance in Tan wire between HO2S 1 harness connector terminal "A" and PCM harness connector C1 terminal No. 12. After repairs, go to step 17.
12. Check for exhaust leaks upstream of HO2S 1. Leak may be very small and will typically be within 12 inches of sensor. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
13. Allow engine to cool to ambient temperature. Using DVOM, recheck resistance between HO2S 1 harness connector terminal "A" (Tan wire) and one of the PCM ground circuit terminals (PCM terminals No. 16, 56 or 57). See WIRING DIAGRAMS. If resistance is less than 500 ohms, go to step 15. If resistance is not less than 500 ohms, go to next step.
14. Remove HO2S 1. Clean sensor mounting threads. Apply anti-seize compound to sensor threads. Tighten HO2S to specification. Using DVOM, recheck resistance between HO2S 1 harness connector terminal "A" (Tan wire) and one of the PCM ground circuit terminals (PCM terminals No. 16, 56 or 57). See WIRING DIAGRAMS. If resistance is less than 500 ohms, go to step 17. If resistance is not less than 500 ohms, go to next step.
15. Replace HO2S 1 sensor. After replacing sensor, go to step 17.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S02732380872001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine and allow idle to stabilize for about one minute. Engine should be at normal operating temperature. Using scan tool, monitor HO2S heater current. If current is 0.25-0.85 amp, problem is intermittent. If current is not 0.25-0.85 amp, go to next step.
3. Turn ignition off. Check fuse (15-amp) to HO2S 1 ignition 1 voltage circuit. Fuse is located in underhood fuse/relay block. If fuse is open, go to step 13. If fuse is okay, go to next step.
4. Turn ignition on, with engine off. Disconnect HO2S 1 harness connector. Connect a test light to a known-good ground and probe HO2S 1 harness connector terminal "D" (Pink wire). see scheme 2 If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
5. Connect test light between HO2S 1 harness connector terminals "A" (Tan wire) and "D" (Pink wire). Start engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 7.
6. Turn engine off. Turn ignition on, with engine off. If test light illuminates, go to step 10. If test light does not illuminate, go to step 11.
7. Turn ignition off. Disconnect PCM harness connector. Using DVOM, check resistance in Black/White wire between PCM harness connector C2 terminal No. 37 and HO2S harness connector terminal "C". If resistance is 0-5 ohms, go to step 14. If resistance is not 0-5 ohms, go to step 9.
8. Turn ignition off. Repair open in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse/relay block. After repairs, go to step 16.
9. Repair open or high resistance Black/White wire between HO2S 1 harness connector terminal "C" and PCM harness connector C2 terminal No. 37. After repairs, go to step 16.
10. Check for short to ground in Black/White wire between HO2S 1 harness connector terminal "C" and PCM harness connector C2 terminal No. 37. After repairs, go to step 16. If circuit is okay, go to step 14.
11. Turn ignition off. Check for poor connections or poor terminal tension at HO2S 1 harness connector. Repair or replace as necessary. After repairs, go to step 16. If connections or terminals are okay, go to next step.
12. Replace HO2S 1. After replacing sensor, go to step 16.
13. Locate and repair short to ground in Pink wire between HO2S 1 harness connector terminal "D" and underhood fuse block. Replace fuse. After repairs, go to step 16.
14. Check for poor connections or terminal tension at PCM harness connector. Repair as necessary. After repairs, go to step 16. If connections or terminal tension is okay, go to next step.
15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
16. Start engine and allow idle to stabilize for about one minute. Engine should be at normal operating temperature. Using scan tool, monitor HO2S heater current. If heater current is 0.25-0.85 amp, go to next step. If heater current is not 0.25-0.85 amp, go to step 2.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Review CAPTURED INFO using scan tool. If any undiagnosed DTCs are displayed, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Reviewing FAILURE RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Ensure engine at normal operating temperature. Operate vehicle within conditions for setting this DTC. Using scan tool, monitor HO2S 2 voltage. If voltage reading is less than 30 millivolts, go to step 4. If voltage reading is not less than 30 millivolts, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review and record scan tool FAILURE RECORDS data. Operate vehicle within the FAILURE RECORDS conditions. Using scan tool, monitor the SPECIFIC DTC INFO for this DTC and until DTC test runs. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-117480-S15702531202001082000000).
4. Turn ignition off. Disconnect HO2S 2 harness connector. Connect a jumper wire between ground and HO2S 2 harness connector terminal "A" (Tan/White wire). see scheme 7 Turn ignition on. If voltage reading is about 450 millivolts, go to step 8. If voltage reading is not about 450 millivolts, go to next step.
5. Turn ignition off. Disconnect PCM harness connectors. Check Purple/White wire at HO2S 2 harness connector terminal "B" for short to ground or short to Tan/White wire at HO2S 2 harness connector terminal "A". Repair as necessary. After repairs, go to next step. If circuits are okay, go to step 7.
6. Repair HO2S 2 high signal circuit (Purple/White wire). After repairs, go to step 9.
7. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
8. Replace HO2S 2 sensor. After replacing sensor, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S22180246572001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
10. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool display any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Ensure HO2S 2 sensor harness is routed correctly and not contacting exhaust system. Check for faulty PCM grounds. See WIRING DIAGRAMS article. Check fuel system. See BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article.

Check for vacuum leaks at intake manifold, throttle body, EGR system and crankcase ventilation system. Check for exhaust leaks in front of HO2S 2. Disconnect MAF sensor connector and see if lean condition is corrected. If lean condition is corrected, replace MAF sensor. Check for fuel contamination.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Ensure engine at operating temperature. Operate vehicle within conditions for setting this DTC. Using scan tool, monitor HO2S 2 voltage. If voltage reading is greater than 999 millivolts, go to step 4. If voltage reading is not greater than 999 millivolts, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review and record scan tool FAILURE RECORDS data. Operate vehicle within the FAILURE RECORDS conditions. Monitor SPECIFIC DTC INFO for this DTC and until this DTC test runs. If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-117480-S41512925242001082000000).
4. Turn ignition off. Disconnect HO2S 2 harness connector. Connect a jumper wire between a known-good ground and HO2S 2 harness connector terminal "A" (Tan/White wire). see scheme 7 Turn ignition on. If voltage reading is about 450 millivolts, go to step 8. If voltage reading is not about 450 millivolts, go to next step.
5. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM, check voltage between ground and PCM harness connector C2 terminal No. 11 (Purple/White wire). see scheme 4 If voltage reading is greater than 999 millivolts, go to next step. If voltage reading is not greater than 999 millivolts, go to step 7.
6. Turn ignition off. Repair short to voltage in circuit. After repairs, go to step 9.
7. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to step 9.
8. Turn ignition off. Replace HO2S 2. After replacing sensor, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S10580767462001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
10. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check if fuel pressure is too high. PCM can compensate for some increase; however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article. Check EVAP system for fuel saturation. Check MAF sensor. Check oxygen sensor for silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, reset fuel trim values. Start engine. Observe HO2S voltage on scan tool. If HO2S voltage is fixed within 412-500 millivolts, go to step 4. If HO2S voltage is not fixed within 412-500 millivolts, go to next step.
3. Turn ignition off. The condition that set this DTC is not present. DTC may have been set by water intrusion in HO2S connector, intermittently open HO2S high signal circuit or low signal circuit, high resistance to ground in HO2S low signal and PCM ground circuits, inoperative HO2S heater, poor HO2S or PCM connector terminal contact, exhaust system leak, or a defective HO2S. Repair as necessary. After repairs, go to step 17. If no problem is found, condition is intermittent.
4. Turn ignition off. Disconnect HO2S harness connector. Connect a jumper wire between a known-good ground and HO2S harness connector terminal "A" (Tan or Tan/White wire). see scheme 2or see scheme 7. Connect a jumper wire between a known-good ground and HO2S harness connector terminal "B" (Purple or Purple/White wire). Turn ignition on, with engine off. Using scan tool, observe HO2S voltage. If voltage reading is less than 20 millivolts, go to step 7. If voltage reading is not less than 20 millivolts, go to next step.
5. Turn ignition off. Remove jumper wires from HO2S terminals. Disconnect PCM harness connectors. Using a DVOM, check continuity of Purple or Purple/White wire between HO2S and PCM. Check continuity of Tan or Tan White wire between HO2S and PCM. If individual resistance of both circuits is less than 5 ohms, go to next step. If individual resistance of both circuits is not less than 5 ohms, go to step 9.
6. Check for proper PCM connector terminal contact. Repair as necessary. After repairs, go to step 17. If connector terminal contacts are okay, go to step 16.
7. Turn ignition off. Remove jumper wires HO2S terminals. Connect a test light between HO2S harness connector terminals "C" (Black or Black/White wire) and "D" (Pink wire). Start engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10.
8. Turn ignition off. Reconnect HO2S harness connector. Disconnect PCM harness connectors. Using DVOM, check resistance between HO2S harness connector terminal "A" (Tan or Tan/White wire) and PCM harness connector C1 terminal No. 12 (Tan wire) or terminal No. 28 (Tan/White wire). see scheme 4 If resistance is less than 500 ohms, go to step 12. If resistance is not less than 500 ohms, go to step 11.
9. Repair circuit with high resistance. After repairs, go to step 17.
10. Turn ignition off. Repair open or high resistance in Pink wire, Black or Black/White wire between HO2S and PCM, or repair poor ground connection or an open heater fuse. If any of this problem was present, a DTC will be set. Diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). After repairs, go to step 17.
11. Repair high resistance between Tan or Tan/white wire and PCM ground circuit. Problem can be caused by poor HO2S connector terminal contact, open sensor harness low signal circuit (requires HO2S replacement), sensor harness low signal circuit with high resistance (requires HO2S replacement) or a poor PCM ground connection. Problem could also be caused by a high PCM ground circuit resistance or an ungrounded exhaust system. After repairs, go to step 17.
12. Check for exhaust system leaks upstream of suspect HO2S. The leak may be very small and will typically be within 12 inches of suspect HO2S. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
13. Allow engine to cool to ambient temperature. Using DVOM, measure resistance between a PCM circuit ground terminal and PCM harness connector C1 terminal No. 12 (Tan wire) or terminal No. 28 (Tan/White wire). If resistance is 13 ohms, go to step 15. If resistance is not 13 ohms, go to next step.
14. Remove HO2S and clean HO2S mounting threads. Apply anti-seize compound to sensor threads. Tighten HO2S to 30 ft. lbs. (41 N.m). Reconnect HO2S harness connector. Using DVOM, measure resistance a PCM circuit ground terminal and between PCM harness connector C1 terminal No. 12 (Tan wire) or terminal No. 28 (Tan/White wire). If resistance is less than 500 ohms, go to step 17. If resistance is not less than 500 ohms, go to next step.
15. Replace HO2S 2. After replacing sensor, go to step 17.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S32635514922001111000000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Ensure engine is at normal operating temperature. Operate engine at greater than 1200 RPM for 2 minutes while monitoring HO2S 2 voltage on scan tool. If voltage varies outside of 412-500 millivolts range, go to next step. If voltage does not vary outside of 412-500 millivolts range, go to step 4.
3. Turn ignition on, with engine off. Using scan tool, review and record scan tool FREEZE FRAME/FAILURE RECORDS. Operate vehicle within FREEZE FRAME/FAILURE RECORDS conditions. Monitor SPECIFIC DTC INFO for this DTC and until this DTC test runs. If DTC resets, go to next step. If DTC does not reset, problem is intermittent.
4. Turn ignition off. Disconnect HO2S 2 harness connector. Jumper HO2S 2 harness connector terminals "A" (Tan/White wire) and "B" (Purple/Tan wire) to ground. see scheme 7 Turn ignition on, with engine off. Using scan tool, monitor HO2S 2 voltage. If voltage reading is less than 150 millivolts, go to step 8. If voltage reading is not less than 150 millivolts, go to next step.
5. Remove jumper wire from HO2S 2 harness connector terminal "B" (Purple/White wire). Leave HO2S 2 harness connector terminal "A" (Tan/White wire) jumper connected to ground. Using a DVOM, measure voltage between HO2S 2 harness connector terminals "B" (Purple/White wire) and "C" (Black wire). If voltage reading is about 400 millivolts, go to next step. If voltage reading is not about 400 millivolts, go to step 7.
6. Turn ignition off. Disconnect PCM harness connector. Check resistance of Tan/White wire between HO2S 2 harness connector terminal "A" and PCM harness connector C1 terminal No. 28. If resistance is greater than 5 ohms, repair circuit. After repairs, go to step 13. If resistance is not greater than 5 ohms, go to step 9.
7. Turn ignition off. Disconnect PCM harness connector. Check resistance of Tan/White wire between PCM harness connector C1 terminal No. 28 and HO2S 2 harness connector "A". Check resistance of Purple/White wire between PCM harness connector C2 terminal No. 11 and HO2S 2 harness connector terminal "B". If resistance readings are greater than 5 ohms, repair affected circuit. After repairs, go to step 13. If resistance readings are not greater than 5 ohms, go to step 10.
8. Turn ignition off. Check HO2S 2 harness connector terminals "A" (Tan/White wire) and "B" (Purple/White wire) for poor connection at HO2S 2 harness connector. Repair as necessary. After repairs, go to step 13. If connections are okay, go to step 11.
9. Check PCM harness connector C1 terminal No. 28 (Tan/White wire) for poor connection at PCM. Repair as necessary. After repairs, go to step 13. If connections is okay, go to step 12.
10. Check PCM harness connector C2 terminal No. 11 (Purple/White wire) for poor connection at PCM. Repair as necessary. After repairs, go to step 13. If connections is okay, go to step 12.
11. Replace HO2S 2. After replacing sensor, go to step 13.
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S39082045622001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. If connections and harness appear okay, observe HO2S 2 display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, monitor HO2S 2 voltage. If voltage goes from bias voltage to greater than 600 millivolts or less than 300 millivolts within 2 minutes, problem is intermittent. If voltage does not go from bias voltage to greater than 600 millivolts or less than 300 millivolts within 2 minutes, go to next step.
3. Check fuse for HO2S 2 ignition 1 voltage circuit. Fuse is located in underhood fuse/relay block. If fuse is open, go to step 15. If fuse is okay, go to next step.
4. Raise and support vehicle. Disconnect HO2S 2 harness connector. Connect a test light to a known-good ground and probe HO2S 2 harness connector terminal "D" (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 7.
5. Connect test light between HO2S 2 harness connector terminals "C" (Black wire) and "D" (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
6. Turn ignition off. Allow HO2S to cool for at least 10 minutes. Using a DVOM, check resistance between HO2S pigtail terminals "C" (Black wire) and "D" (Pink wire). If resistance is 4-6 ohms, go to step 9. If resistance is not 4-6 ohms, go to step 14.
7. Turn ignition off. Repair open in Pink wire between underhood fuse block and HO2S 2. After repairs, go to step 16.
8. Turn ignition off. Repair open in Black wire between HO2S 2 and ground. After repairs, go to step 16.
9. Check HO2S 2 harness terminals for poor connection. Repair as necessary. After repairs, go to step 16. If connection is okay, go to next step.
10. Disconnect PCM harness connector. Check resistance between PCM harness connector C1 terminal No. 28 (Tan/White wire) and PCM harness connector C2 terminal No. 11 (Purple/White wire). see scheme 4 If resistance is greater than 5 ohms, repair as necessary. After repairs, go to step 16. If resistance it not greater than 5 ohms, go to next step.
11. Check for poor connections at HO2S 2 harness connector terminals "A" (Tan/White wire) and "B" (Purple/White wire). Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
12. Check PCM harness connector C1 terminal No. 28 (Tan/White wire) for poor connection at PCM. Repair as necessary. After repairs, go to step 16. If connection is okay, go to next step.
13. Check PCM harness connector C2 terminal No. 11 (Purple/White wire) for poor connection at PCM. Repair as necessary. After repairs, go to step 16. If connection is okay, go to next step.
14. Replace HO2S 2. After replacing sensor, go to step 16.
15. Turn ignition off. Repair short to ground in Pink wire between HO2S 2 and underhood fuse block. Replace fuse. After repairs, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S12691043152001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. If connections and harnesses appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Ensure no other DTCs are set. Start and operate engine at idle and at normal operating temperature, and in closed-loop. Using scan tool, record the LONG TERM FUEL TRIM data. Turn engine off. Turn ignition on, with engine off. Review FREEZE FRAME/FAILURE RECORDS and record displayed data for this DTC. If scan tool indicates that Long Term Fuel Trim is greater than 23 percent, go to next step. If Long Term Fuel Trim is not greater than 23 percent, see «DIAGNOSTIC AIDS»(ref-117480-S15783094332001082000000) .
3. Start and operate engine at idle. Using scan tool, observe HO2S parameters. If scan tool indicates that values are within 200-800 millivolts and fluctuating, go to next step. If values are not within 200-800 millivolts or not fluctuating, go to step 5 .
4. Turn engine off. Check vacuum hoses for splits, kinks, and proper connections. Ensure vehicle has sufficient fuel in tank. If fuel pressure is too low, this DTC may set. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to step 6 .
5. Turn engine off. Check HO2S for proper installation. Ensure harness connectors and wires are secured and not contacting exhaust system. Check for HO2S 2 circuits for short to each other. Repair as necessary. After repairs, go to step 7 . If no problem is found, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS (GASOLINE) in appropriate BASIC DIAGNOSTIC PROCEDURES article.
6. Operate engine at idle. Check for missing, loose or leaking exhaust components forward of HO2S. Check for vacuum leaks at intake manifold, throttle body or injector "O" rings. Check air induction system and air intake ducts for leaks. Check AIR system for leaks, improper air delivery or shut-off valve not closing. Check crankcase ventilation system for leaks. Repair as necessary. After repairs, go to next step. If no problem is found, diagnose for engine mechanical problem.
7. After repairs, use scan tool to reset the Long Term Fuel Trim. After resetting fuel trim, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S26218656992001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

The system will go lean if an injector is not supplying enough fuel. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel. Fuel contamination, such as water and alcohol will affect fuel trim.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck for DTCs. If any DTCs are set, other than P0172, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no other DTCs are set, start operate engine at idle and warm to normal operating temperature. Ensure engine is operating in closed-loop. Using scan tool, record the Long Term Fuel Trim data. Turn engine off. Turn ignition on, with engine off. Review FREEZE FRAME/FAILURE RECORDS and record displayed data for this DTC. If scan tool indicates that long term fuel trim is less than -13 percent, go to next step. If long term fuel trim is not less than -13 percent, see «DIAGNOSTIC AIDS»(ref-117480-S29366177052001082000000) .
3. Operate engine at idle. Using scan tool, observe HO2S parameters. If values are within 200-800 millivolts and fluctuating, go to next step. If values are not within 200-800 millivolts and fluctuating, go to step 5 .
4. Turn engine off. Check MAF sensor inlet screen for blockage. Check vacuum hoses for splits, kinks and proper connections. Check for collapsed or restricted air intake duct. Check dirty or restricted air filter or for objects blocking throttle body. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to step 6 .
5. Turn engine off. Check HO2S for proper installation. Ensure harness connectors and wires are secured and not contacting exhaust system. Repair as necessary. After repairs, go to next step. If no problem is found, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS (GASOLINE) in appropriate BASIC DIAGNOSTICS PROCEDURES article.
6. Check for excessive fuel in crankcase. Check evaporative emissions control system. Check fuel pressure regulator for proper operation. Ensure all injectors are functioning properly. Repair as necessary. After repairs, go to next step. If no problem is found, diagnose engine for mechanical problem.
7. After repairs, use scan tool to reset the Long Term Fuel Trim, then clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S35982514322001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for poor connection at PCM. Check for damaged wiring harness. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, clear DTCs. Operate engine at idle and at normal operating temperature. Using scan tool, monitor misfire current counters. If any of the misfire current counters are incrementing, go to step 4 . If misfire current counters are not incrementing, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S00268999522001091700000) . If DTC fails this ignition, go to next step. If DTC did not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S27508698982001082000000) .
4. Turn ignition off. Disconnect fuel injector harness connector. Using a test light connected to battery voltage, probe appropriate fuel injector control circuit. See WIRING DIAGRAMS article. Crank engine. If test light blinks when cranking engine, go to step 8 . If test light does not blink when cranking engine, go to next step.
5. If test light stays on at all times, go to step 7 . If test light is not on at all times, go to next step.
6. Check affected fuel injector control circuit for short to voltage or open between the fuel injector harness connector and PCM. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 14 .
7. Check affected fuel injector control circuit for short to ground between the fuel injector harness connector and PCM. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 17 .
8. Check the accessible fuel injector jumper harness between the multi-way harness connector and plenum for poor connections at multi-way connector, damaged, pinched or broken wires inside insulation. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
9. Remove upper intake. Using test light connected to battery voltage, probe appropriate fuel injector control circuit on fuel injector harness connector and at the multi-way connector. If test light illuminates, go to step 15 . If test light does not illuminate, go to next step.
10. Using DVOM, check continuity of affected fuel injector control circuit between injector harness connector terminal and multi-way connector. If continuity does not exist, go to next step. If continuity exists, go to step 13 .
11. Check fuel injector control circuit for open or poor connections at fuel injector. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to next step.
12. Check fuel injector ignition voltage circuit for open between fuel injector and splice. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 16 .
13. Check fuel injector control circuit for short to voltage or short to another circuit. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 16 .
14. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to step 17 .
15. Repair short to ground in affected fuel injector control circuit. After repairs, go to step 18 .
16. Replace appropriate fuel injector. After replacing injector, go to step 18 .
17. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
18. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S00268999522001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
19. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Monitor injector fault parameter on scan tool. Wiggle electrical harnesses for affected electrical circuit. If status changes on scan tool, an intermittent problem is present. Check for poor connections at PCM. Check for damaged harness.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command fuel pump on and off. If fuel pump relay turns on and off with each command, go to next step. If fuel pump relay does not turn on and off with each command, go to step 4 .
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S27313406332001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Remove fuel pump relay. Fuel pump relay is located in underhood fuse/relay block. Turn ignition on, with engine off. Using a test light connected to ground, probe fuel pump relay control circuit (Dark Green/White wire) at underhood fuse/relay block. See WIRING DIAGRAMS article. Using scan tool, command fuel pump on and off. If test light turns on and off with each command, go to next step. If test light does not turn on and off, go to step 6 .
5. Connect test light between fuel relay control circuit (Dark Green/White wire) and fuel pump relay ground circuit (Black/White wire) at underhood fuse relay block. Using scan tool, command fuel pump 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 step 11 .
6. If test light remains illuminated with each command, go to step 8 . If test light does not remain illuminated with each command, go to next step.
7. Turn ignition off. Check fuel pump relay control circuit (Dark Green/White wire) for short to ground or open circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 10 .
8. Turn ignition off. Check fuel pump relay control circuit (Dark Green/White wire) for short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 10 .
9. Turn ignition off. Check for poor connections at fuel pump relay. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
10. Turn ignition off. Check for poor connections at PCM harness connectors. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
11. Turn ignition off. Repair fuel pump relay ground circuit. After repairs, go to step 14 .
12. Replace fuel pump relay. After replacing relay, go to step 14 .
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S27313406332001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
15. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

An intermittent may be caused by a poor connection, rubbed-through wire insulation or a wire broken inside of insulation. Check for poor connections at PCM or fuel pump relay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If are any other DTCs are set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no other DTCs are set, go to next step.
3. Start and operate engine at idle. Using scan tool, review and record scan tool FREEZE FRAME data. Operate vehicle to duplicate the conditions present when DTC was set (as defined by FREEZE FRAME data. Monitor Misfire Current Cyl # display for each cylinder. If Misfire Current # display is incrementing for any cylinder, indicating a misfire currently occurring, go to step 5 . If Misfire Current # display is not incrementing for any cylinder, go to next step.
4. View Misfire History Cyl # display on scan tool. If Misfire History Cyl # displays a very large value for more than one cylinder, go to next step. If Misfire History Cyl # does not display a very large value for more than one cylinder, go to step 8 .
5. If misfire values displayed on the Misfire History Cyl # is related to the companion cylinders (i.e. 1/4, 2/5, 3/6), go to step 9 . If misfire values displayed on the Misfire History Cyl # is not related to the companion cylinders, go to next step.
6. Check for excessive vibration from sources other than the engine. Check vacuum hoses and crankcase ventilation system for vacuum leaks. Check throttle body and intake manifold for vacuum leaks. Check PCM grounds, spark plug wires, EGR valve to exhaust manifold pipe for proper connections and signs of damage. For PCM grounds, see WIRING DIAGRAMS article. Check for fuel contamination. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
7. Install fuel pressure gauge. Turn ignition on, with engine off. Using scan tool, command fuel pump on. Monitor fuel pressure with fuel pump running. If fuel pressure is 52-59 psi (358-405 kPa), go to next step. If fuel pressure is not 52-59 psi (358-405 kPa), diagnose fuel system. See BASIC FUEL SYSTEM CHECKS (GASOLINE) in appropriate BASIC DIAGNOSTIC PROCEDURES article.
8. Check fuel injector. See appropriate FUEL SYSTEM (GASOLINE) in appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
9. Check ignition wires and coils associated with misfiring cylinders for carbon tracking/arching and damage. Check for incorrect connection to cylinders at coil and spark plug. Check for poor terminal connections at coil and spark plug. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
10. Install Spark Tester (J-26792) at spark plug end of ignition wire associated with the misfiring cylinders. Jumper spark plug end of the companion cylinder ignition wire to engine ground (i.e. 1/4, 2/5, 3/6). Crank engine while observing spark tester. If spark is present, go to step 15 . If no spark is present, go to next step.
11. Check resistance of ignition wires associated with cylinders that were indicated as misfiring. Resistance should be greater than 3000 ohms per foot. Replace as necessary. After replacing wires, go to step 18 . If wires are okay, go to next step.
12. Check resistance of secondary ignition coils associated with the misfiring cylinders. Resistance should be 5000-8000 ohms. Replace as necessary. After replacing ignition coil(s), go to step 18 . If ignition coil(s) are okay, go to next step.
13. Remove ignition coils associated with the misfiring cylinders. Check coils for signs of carbon tracking, cracks or other damage. Repair as necessary. After repairs, go to step 18 . If ignition coils are okay, go to next step.
14. Leave ignition coils disconnected. Connect a test light across the ignition module primary circuit terminals. Remove fuel injector fuse (located in underhood fuse/relay block). Observe test light while cranking engine. If test light blinks, go to step 16 . If test light does not blink, go to step 17 .
15. Remove and check spark plug from cylinders associated with the misfire. Replace as necessary. After replacing spark plugs, go to step 18 .
16. Reinstall fuel injector fuse. Replace ignition coil(s) associated with misfiring cylinders. After replacing ignition coil(s), go to step 18 .
17. Reinstall fuel injector fuse. Replace ignition coil(s) associated with misfiring cylinders. After replacing ignition coil(s), go to next step.
18. Review and record FREEZE FRAME data. Clear DTCs. Operate vehicle to duplicate the conditions present when DTC was set, as defined by FREEZE FRAME data. Monitor the scan tool Misfire Current Cyl # display for each cylinder. If Misfire Current Cyl # display is incrementing for any cylinder (indicating a misfire currently occurring), diagnose for a mechanical engine problem. If Misfire Current Cyl # display is not incrementing, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S09176283672001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
4. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S09176283672001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
5. Using scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connection at PCM. Check KS connector for proper connection or damage.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, monitor 24X crank sensor and CAM signal. If 24X and CAM signals are present, go to next step. If 24X cranks and CAM signals are not present, go to «DTC P0336»(ref-117480-S31985134432001082000000) .
3. If a mechanical engine knock can be heard, repair engine mechanical problem before proceeding with this test. Using scan tool, observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S37803390952001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Disconnect KS harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between ground and KS harness connector terminal No. 1 (Dark Blue wire). If voltage reading is zero volts, go to step 6 . If voltage reading is not zero volts, go to next step.
5. Turn ignition off. Repair short to voltage in KS signal circuit (Dark Blue wire). After repairs, go to step 10 .
6. Turn ignition off. Disconnect the PCM harness connector. Check for open or short to ground in Dark Blue wire between KS and PCM harness connectors. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
7. Check KS signal circuit (Dark Blue wire) for poor terminal connection at sensor. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
8. Check KS signal circuit (Dark Blue wire) for a poor terminal connection at PCM. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
9. Replace knock sensor. After replacing sensor, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S37803390952001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
11. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connection at PCM or KS. Ensure KS harness is not routed too close to high-voltage wires, such as spark plug cables, ignition coils or other high-voltage components.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Start engine. Using scan tool, observe the 24X RPM. If 24X RPM vary with engine speed up to about 1600 RPM, go to next step. If 24X RPM does not vary with engine speed, go to step 4.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS observed. See «CODE ENABLE CRITERIA»(ref-117480-S24280897282001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S40225923422001082000000).
4. Turn ignition off. Disconnect 24X CKP sensor "A" harness connector. Turn ignition on, with engine off. Connect a DVOM between ground and CKP sensor "A" harness connector terminal "A" (Light Green wire). see scheme 8 If voltage reading is about battery voltage, go to step 6. If voltage reading is not about battery voltage, go to next step.
5. Turn ignition off. Disconnect PCM harness connector. Check Light Green wire between PCM harness connector C2 terminal No. 70 and CKP sensor "A" harness connector terminal "A" for short to ground or open circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
6. Connect a test light to battery voltage. Touch test light to CKP sensor "A" harness connector terminal "C" (Yellow/Black wire). If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
7. Turn ignition off. Disconnect PCM harness connector. Check PCM harness connector C2 terminal No. 74 (Yellow/Black wire) for open circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
8. Using scan tool, monitor 24X RPM. Using a fused jumper wire connected to battery positive voltage, momentarily touch CKP sensor "A" harness connector terminal "B" (Light Blue/Black wire) 5 times for a duration of one second each. If 24X RPM changes each time the signal circuit is touched, go to step 13. If 24X RPM does not change each time the signal circuit is touched, go to next step.
9. Check fuse in jumper wire. If fuse is open, go to step 11. If fuse is okay, go to next step.
10. Turn ignition off. Check Light Blue/Black wire between CKP sensor "A" and PCM harness connectors for short to voltage or open circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
11. Turn ignition off. Check Light Blue/Black wire between CKP sensor "A" and PCM harness connectors for short to ground. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to next step.
12. Turn ignition off. Check for faulty connections at PCM harness connector. Repair as necessary. After repairs, go to step 16. If connections are okay, go to step 14.
13. Turn ignition off. Check for faulty connections at CKP sensor "A" harness connector. Repair as necessary. After repairs, go to step 16. If connections are okay, go to step 15.
14. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to step 16.
15. Replace CKP sensor "A". After replacing sensor, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S24280897282001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Turn ignition on, with engine off. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for secondary ignition wire(s) arcing to wiring harness.

Check for faulty connections or damaged harness. Observe a voltmeter connected to 24X CKP sensor "A" reference circuit at PCM harness connector while moving all related harness and connectors. A change in voltage indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, monitor CMP sensor input signal in Engine Data List 2. If scan tool indicates that CMP sensor signal is present, go to next step. If CMP sensor signal is not present, go to step 4.
3. Observe FREEZE FRAME/FAILURE RECORDS data. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S11971598962001091700000). If DTC resets, go to next step. If DTC does not reset, see «DIAGNOSTIC AIDS»(ref-117480-S23260590242001082000000).
4. Turn ignition off. Disconnect CMP sensor harness connector. Turn ignition on, with engine off. Check voltage between chassis ground and CMP sensor harness connector terminal "A" (Red/White wire). see scheme 8 If voltage reading is about battery voltage, go to step 6. If voltage reading is not about battery voltage, go to next step.
5. Turn ignition off. Disconnect PCM harness connector C2. Check for short to ground or open in Red/White wire between CMP sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 72. see scheme 4 Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
6. Connect a test light to battery positive voltage. Touch test light to CMP sensor harness connector terminal "C" (Black wire). If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
7. Turn ignition off. Disconnect PCM harness connector C2. Check for open in Black wire between CMP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 73. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
8. Using scan tool, monitor cam signal. Connect a fused jumper wire to battery voltage and momentarily touch CMP sensor harness connector terminal "B" (Black wire) 5 times for a duration of one second each. If cam signal changes each time the signal circuit is touched, go to step 14. If cam signal does not changes each time signal circuit is touched, go to next step.
9. Check fuse in jumper wire. If fuse is open, go to step 11. If fuse is okay, go to next step.
10. Turn ignition off. Check for short to voltage or open in Black wire between CMP sensor harness connector terminal "B" and PCM harness connector C1 terminal No. 7. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
11. Turn ignition off. Check for short to ground in Black wire between CMP sensor harness connector terminal "B" and PCM harness connector C1 terminal No. 7. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to next step.
12. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to step 16.
14. Turn ignition off. Check for poor connections at CMP sensor. Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
15. Replace CMP sensor. After repairs, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S11971598962001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, review the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for secondary ignition wire(s) arcing to wiring harness.

Check for faulty connections or damaged harness. Observe DVOM connected to CMP sensor signal circuit at PCM harness connector while moving all related harness and connectors. A change in voltage indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If any MAP related DTCs are set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no MAP related DTCs are set, go to next step.
3. Check exhaust system for modification of original installed parts or leaks. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to next step.
4. Check EGR valve gasket and pipe for leaks. Repair or replace as necessary. After repairs, go to step 7 . If no problem is found, go to next step.
5. Remove EGR valve. Check for a leak and/or a restriction. Check EGR pintle and valve passages. Repair as necessary. After repairs, go to step 7 . If no problem is found, go to next step.
6. Remove EGR inlet pipe from exhaust manifold. Check manifold EGR ports and EGR inlet pipe for blockage caused by excessive deposits or other damage. Repair as necessary. After repairs, go to next step. If no problem is found, see «DIAGNOSTIC AIDS»(ref-117480-S31543129232001082000000) .
7. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S38261031532001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
8. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

PCM will only run EGR flow test during gradual deceleration, a closed throttle condition and with vehicle speed greater than 20 MPH. Accelerate vehicle to greater than 20 MPH, and gradually decelerate 9-13 times.

Check for faulty connections or damaged harness. Check PCM harness connector EGR control circuit for backed-out terminal. Observe ACTUAL EGR POSITION display on scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or plugged catalytic converter.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EGR from zero percent to 100 percent. If EGR position sensor remains close to the desired EGR position at all commanded positions, go to next step. If EGR position sensor does not remain close to the desired EGR position at all commanded positions, go to step 4.
3. Observe the FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S08713142172001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Disconnect EGR solenoid harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe EGR solenoid harness connector terminal "E" (Red wire). see scheme 9 Using scan tool, command EGR between 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 6.
5. Connect test light between EGR solenoid harness connector terminals "B" (Black wire) and "E" (Red wire). Using scan tool, command EGR between 0-10 percent. 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 step 9.
6. If test light remains illuminated with each command, go to step 8. If test light does not remain illuminated with each command, go to next step.
7. Turn ignition off. Check for short to ground or open in Red wire between EGR solenoid harness connector terminal "E" and PCM harness connector C2 terminal No. 4. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 11.
8. Turn ignition off. Check for short to voltage in Black wire between EGR solenoid harness connector terminal "B" and PCM harness connector C1 terminal No. 31. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 11.
9. Turn ignition off. Check for open or high resistance in Black wire between EGR solenoid harness connector terminal "B" and PCM harness connector C1 terminal No. 31. Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 11.
10. Turn ignition off. Check for poor connections at EGR harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 12.
11. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 13.
12. Replace EGR valve. After replacing EGR valve, go to step 14.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S08713142172001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
15. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for poor connection at PCM or EGR valve harness connectors.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on. Using scan tool, check if DTC P0403 or P0405 is present. If DTC P0403 or P0405 is not present, diagnose affected DTC first. If DTC P0403 or P0405 is not present, select EGR OUTPUT CONTROL function. Increment EGR valve through all positions while comparing desired to actual EGR position. If desired and actual EGR position remains close to each other at all commanded positions, go to next step. If desired and actual EGR position is not within range, go to step 4.
3. Using scan tool, review FAILURE RECORDS data. Operate vehicle within FAILURE RECORDS conditions and monitor SPECIFIC DTC info. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(ref-117480-S08946397692001082000000).
4. Disconnect EGR valve harness connector. Check voltage between EGR harness connector terminals "B" (Black wire) and "D" (Gray wire). see scheme 9 If voltage reading is 5 volts, go to next step. If voltage reading is not 5 volts, go to step 10.
5. Using test light connected to battery voltage, probe EGR harness connector terminal "C" (Brown wire). If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
6. Using a fused jumper wire, jumper EGR harness connector terminals "C" (Brown wire) and "D" (Gray wire). Using scan tool, observe actual EGR position. If actual EGR position is 100 percent, go to step 9. If actual EGR position is not 100 percent, go to next step.
7. Turn ignition off. Disconnect PCM harness connector. Check for open in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 15.
8. Turn ignition off. Disconnect PCM harness connector. Using a test light connected to battery voltage, probe EGR harness connector terminal "C" (Brown wire). If test light illuminates, go to step 13. If test light does not illuminate, go to step 14.
9. Turn ignition off. Check for poor terminal connections at EGR valve. Repair as necessary. After repairs, go to step 17. If terminal connections are okay, go to step 12.
10. Turn ignition off. Check for open or short to ground in Gray wire between EGR harness connector "D" and PCM harness connector C2 terminal No. 30. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to next step.
11. Check for open or short to voltage in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 15.
12. Replace EGR valve. After replacing EGR valve, go to step 17.
13. Turn ignition off. Locate and repair short to ground in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. After repairs, go to step 17.
14. Check for short between Brown wire at EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28 and Black wire at EGR harness connector terminal "B" and PCM harness connector C1 terminal No. 31. see scheme 4 Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 16.
15. Check circuits related to EGR valve for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 17. If circuits are okay, go to next step.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, test is complete. If scan tool did not indicate that this test ran and passed, repeat step 2.

Check for excessive deposits on EGR valve pintle or seat. Check for poor connection at PCM or EGR valve harness connectors.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe EGR position sensor voltage parameter. If EGR position sensor voltage is less than 0.35 volt, go to step 4 . If EGR position sensor voltage is not less than 0.35 volt, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S29225923142001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail in this ignition, problem is intermittent.
4. Turn ignition off. Disconnect EGR valve harness connector. Connect a fused jumper wire between EGR harness connector terminals "C" (Brown wire) and "D" (Gray wire). Turn ignition on, with engine off. Using scan tool, observe EGR position sensor parameter. If EGR position sensor parameter is about 100 percent, go to step 10 . If EGR position sensor parameter is not about 100 percent, go to next step.
5. Disconnect fused jumper wire. Using a DVOM, check voltage between EGR harness connector terminals "B" (Black wire) and "D" (Gray wire). If voltage reading is about 5 volts, go to step 9 . If voltage reading is not about 5 volts, go to next step.
6. Turn ignition off. Check for open or high resistance in Gray wire between EGR harness connector terminal "D" and PCM harness connector C2 terminal No. 30. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
7. Check for short to ground in Gray wire between EGR harness connector terminal "D" and PCM harness connector C2 terminal No. 30. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to next step.
8. Connect DVOM between EGR harness connector terminals "B" (Black wire) and "D" (Gray wire). Observe voltage while disconnecting all sensors that use a 5-volt reference signal, one at a time. A change in voltage indicates a faulty component. Replace affected component(s) as necessary. After replacing component(s), go to step 15 . If voltage does not change, go to step 11 .
9. Turn ignition off. Check for short to ground, high resistance or open in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step 15 . If circuit is okay, go to step 11 .
10. Turn ignition off. Check for short between Brown wire at EGR harness connector terminal "C" and Red wire at EGR harness connector terminal "E". Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to step 12 .
11. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to step 14 .
12. Check for poor connections at EGR harness connector. Repair as necessary. After repairs, go to step 15 . If connections are okay, go to next step.
13. Replace EGR valve. After replacing EGR valve, go to step 15 .
14. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
15. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S29225923142001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
16. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0412 or P0418 is also set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0412 or P0418 is not set, go to next step.
3. Check AIR pump feed relay fuse, located in underhood fuse/relay block. If fuse is okay, go to next step. If fuse is open, go to step 13 .
4. Turn ignition on, with engine off. Using scan tool, command AIR pump on and off. If AIR pump turns on and off with each command, go to step 10 . If AIR pump does turn on and off, go to next step.
5. If AIR pump operates continuously, go to step 16 . If AIR pump does not operate continuously, go to next step.
6. Remove AIR pump relay (located on right side of engine compartment, behind horn). Using a test light connected to ground, probe relay harness connector terminal No. 85 (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 17 .
7. Using a fused jumper wire, jumper relay harness connector terminals No. 85 (Pink wire) and No. 87 (Red wire). Turn ignition on. If AIR pump operates, go to step 25 . If AIR pump does not operate, go to next step.
8. Leave jumper wire in place. Disconnect AIR pump harness connector. Using test light connected to ground, probe AIR pump harness connector terminal "A" (Red wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 18 .
9. Connect test light between AIR pump harness connector terminals "A" (Red wire) and "B" (Black wire). If test light illuminates, go to step 27 . If test light does not illuminate, go to step 19 .
10. Disconnect AIR pump hose/pipe. Using a scan tool, command AIR pump on. If airflow is present at AIR pump outlet, go to next step. If airflow is not present, go to step 28 .
11. Reconnect AIR hose/pipe to AIR pump. Disconnect AIR hose/pipe from AIR combination valve. Using scan tool, command AIR pump on. If airflow is present at AIR hose/pipe outlet, go to next step. If airflow is not present at AIR hose/pipe outlet, go to step 22 .
12. Start engine. With engine running, test for vacuum at AIR combination valve. If vacuum is not present, check for damaged, pinched or disconnected vacuum line, blocked/restricted vacuum port or faulty vacuum control solenoid valve. Check for damaged, pinched or disconnected vacuum line between vacuum control solenoid and actuator diaphragm. Repair as necessary. After repairs, go to step 23 . If no problem is found, go to step 26 .
13. Turn ignition off. Remove AIR pump relay (located on right front of engine compartment, behind horn). Check for short to ground in relay feed circuit. Repair as necessary. After repairs, go to step 20 . If circuit is okay, go to next step.
14. Disconnect AIR pump harness connector. Check for short to ground in Red wire between AIR pump harness connector terminal "A" and AIR pump relay. Repair as necessary. After repairs, go to step 21 . If circuit is okay, go to next step.
15. Reconnect AIR pump relay. Reconnect AIR pump harness connector. Install a new fuse. Using scan tool, command AIR pump on. Recheck fuse. If fuse opens, go to step 28 . If fuse is okay, see «DIAGNOSTIC AIDS»(ref-117480-S31346581162001082000000) .
16. Remove AIR pump relay (located on right front of engine, behind horn). If AIR pump is still running, go to step 24 . If AIR pump stops running, go to step 25 .
17. Turn ignition off. Repair open relay switch feed circuit. After repairs, go to step 29 .
18. Turn ignition off. Check for open in AIR pump feed circuit. Repair as necessary. After repairs, go to step 29 . If circuit is okay, go to step 25 .
19. Turn ignition off. Repair open or high resistance in AIR pump ground circuit. After repairs, go to step 29 .
20. Repair short to ground in relay switch feed circuit. After repairs, go to step 29 .
21. Repair short to ground in AIR pump feed circuit. After repairs, go to step 29 .
22. Check for blocked or damaged combination valve. Check for restriction, blockage, disconnect or other damage to AIR hoses/pipes from combination valve to exhaust system. Repair as necessary. After repairs, go to step 29 .
23. Turn ignition off. Repair vacuum system as necessary. After repairs, go to step 29 .
24. Turn ignition off. Repair short to voltage in AIR pump feed circuit. After repairs, go to step 29 .
25. Turn ignition off. Replace AIR pump relay. After repairs, go to step 29 .
26. Turn ignition off. Replace affected AIR combination valve. After repairs, go to step 29 .
27. Turn ignition off. Check for poor connections at AIR pump. Repair as necessary. After repairs, go to step 29 . If connections are okay, go to next step.
28. Replace AIR pump. After replacing AIR pump, go to next step.
29. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off and wait 15 seconds. Operate vehicle within conditions required for this diagnostic to run. If this test ran and passed, go to next step. If DTC resets, go to step 2 .
30. Using scan tool, review CAPTURED INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Check PCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on. Using scan tool, command AIR relay on and off. If relay turns on and off with each command, see «DIAGNOSTIC AIDS»(ref-117480-S10649101812001082000000) . If relay does not turn on and off with each command, go to next step.
3. Turn ignition off. Remove AIR pump relay (located on right front of engine compartment, behind horn). Turn ignition on. Using a test light connected to ground, probe AIR pump relay harness connector terminal No. 85 (Pink wire). See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
4. Connect test light between AIR pump relay harness connector terminals No. 85 (Pink wire) and No. 86 (Brown wire). Using scan tool, command AIR solenoid on and off . If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
5. If test light remains on with each command, go to step 7 . If test light does not remain on with each command, go to next step.
6. Turn ignition off. Check for short to voltage or open circuit in Brown wire between relay harness connector terminal No. 86 and PCM harness connector C2 terminal No. 75. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
7. Turn ignition off. Check for short to ground in Brown wire between relay harness connector terminal No. 86 and PCM harness connector C2 terminal No. 75. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
8. Turn ignition off. Check for poor connections at AIR pump relay harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
9. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
10. Turn ignition off. Repair for open or short to ground in AIR solenoid feed circuit. After repairs, go to step 13 .
11. Replace AIR solenoid. After replacing solenoid, go to step 13 .
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S36662965232001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Note. DO NOT operate AIR pump for longer than 60 seconds. Continuous operation of AIR pump will damage pump.

Remove any debris from connector surfaces before servicing a component. Check connector gaskets when diagnosing or replacing a component. Ensure that gaskets are installed correctly.

Check for faulty connections or damaged harness. Check PCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on. Using scan tool, command the AIR pump and relay on and off. If relays turn on and off with each command, see «DIAGNOSTIC AIDS»(ref-117480-S11945208232001082000000) . If relay does not turn on and off with each command, go to next step.
3. Turn ignition off. Remove AIR pump the relay (located on right front of engine compartment, behind horn). Turn ignition on. Using a test light connected to ground, probe AIR pump relay harness connector terminal No. 85 (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
4. Connect test light between relay harness connector terminals No. 85 (Pink wire) and No. 86 (Brown wire). Using scan tool, command AIR pump and solenoid on and off . If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
5. If test light remains on with each command, go to step 7 . If test light does not remain on with each command, go to next step.
6. Turn ignition off. Check for short to voltage or open in relay control circuit (Brown wire). Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 9 .
7. Turn ignition off. Check relay control circuit (Brown wire) for short to ground. If circuit is okay, go to step 9 . If circuit is shorted to ground, repair circuit. After repairs, reconnect all devices and replace all open fuses. Turn ignition on, with engine off. Using scan tool, command AIR pump and solenoid on and off. If pump does not operate, replace AIR pump. After repairs, go to step 13 .
8. Turn ignition off. Check for poor connections at relay connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
9. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
10. Turn ignition off. Repair open or short to ground in relay feed circuit (Pink wire). After repairs, go to step 13 .
11. Replace AIR pump relay. After replacing relay, go to step 13 .
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S25685299252001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Note. DO NOT operate AIR pump for longer than 60 seconds. Continuous operation of AIR pump will damage pump.

Remove any debris from connector surfaces before servicing a component. Check connector gaskets when diagnosing or replacing a component. Ensure that gaskets are installed correctly.

Check for faulty connections or damaged harness. Check PCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Diagnose any other DTCs before proceeding with this test. If no other DTCs are set, go to next step.
3. Turn ignition on, with engine off. Using scan tool, clear DTCs. Ensure A/C is off. Warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Check may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for more than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(ref-117480-S21644772082001082000000) . If scan tool indicates that DTC ran and passed in this ignition cycle, system is okay. If scan tool does not indicate that DTC ran and passed in this ignition cycle, go to next step.
4. Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure no internal damaged catalyst rattle exists. Repair as necessary. After repairs, go to step 9 . If no problem is found, go to next step.
5. Check exhaust system for leaks, damage, loose or missing hardware. Repair as necessary. After repairs, go to step 7 . If no problems are found, go to next step.
6. Turn ignition off. Ensure HO2S 2 is securely installed and that harness is not damaged or contacting exhaust. Repair as necessary. After repairs, go to step 8 . If no problems are found, go to step 9 .
7. Repair exhaust system. After repairs, go to step 10 .
8. Repair HO2S sensor circuit. After repairs, go to step 10 .
9. Replace TWC. Check for possible engine misfire DTC or engine mechanical problem. After repairs, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Ensure A/C is off. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. Check may need to be performed up to 6 times in order to pass or fail. If test has been performed or attempted for greater than 6 times and DTC has not passed or failed this ignition cycle, test may be aborting. See «DIAGNOSTIC AIDS»(ref-117480-S21644772082001082000000) . If scan tool indicates that DTC ran and passed in this ignition cycle, go to next step. If DTC resets, go to step 2 .
11. If additional DTCs are present, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no additional DTCs are present, system okay.

PCM will not enable the catalyst test if

1. Engine speed is plus or minus 100 RPM from desired idle speed.
2. TP sensor is zero percent.
3. Short term integrator is -20 percent and 20 percent.

The catalyst test will abort if vehicle falls out of following the conditions

1. Engine speed is +/-125 RPM from desired idle speed.
2. TP sensor is zero percent.
3. Short term integrator is -20 percent and 20 percent.

The catalyst test may abort due to change in engine load (i.e., A/C, cooling fan on). If this problem occurs, use scan tool to force cooling fans to turn on, then repeat test.

Check for faulty connections or damaged harness. Check PCM harness connector EGR control circuit for backed-out terminal. Observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck DTCs. If DTC P0443 or DTC P0449 is also set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0443 or P0449 is not set, go to next step.
3. Check EVAP system for loose, missing or damaged service port Schrader valve. Check for loose, incorrect, missing or damaged fuel fill cap. Check for damaged EVAP canister purge valve. Raise vehicle on hoist. Check EVAP system for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses. Check for damaged or disconnected EVAP canister vent valve, or damaged or disconnected EVAP canister. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
4. Using scan tool, clear DTCs, then perform the SERVICE BAY CHECK. If test passed, see «DIAGNOSTIC AIDS»(ref-117480-S16153260912001082000000) . If test did not pass, go to next step.
5. Connect Fill Tank Cap Adapter (J-41415-40) to fuel filler neck and fuel filler cap. Connect EVAP Pressure Diagnostic Station (J-41413) to adapter. Turn ignition on, with engine off. Using scan tool, seal the EVAP system. Using diagnostic station, pressurize the system to 5 in. H2O. Move rotary switch on diagnostic station to OFF/HOLD position. Monitor pressure gauge for one minute. If pressure is held at 5 in. H2O, go to next step. If pressure is not held at 5 in. H2O, go to step 8 .
6. Compare pressure reading between the diagnostic station and the scan tool's Fuel Tank Pressure (VTP) sensor value. If reading is close between the diagnostic station and scan tool, go to next step. If reading is not close between the diagnostic station and scan tool, go to step 13 .
7. Using diagnostic station, pressurize EVAP system to 5 in. H2O. Turn rotary switch on diagnostic station to OFF/HOLD position. Monitor pressure gauge on diagnostic station. Using scan tool, command EVAP canister purge valve to 50 percent. If EVAP system pressure decreases, go to step 9 . If EVAP system pressure does not decrease, go to step 10 .
8. Continuously pressurize EVAP system. Using Ultrasonic Leak Detector (J-41416), check for leaks in EVAP system purge pipe, vapor pipe, vent hose/pipe, fuel fill pipe/hose, fuel fill cap, EVAP canister, EVAP canister vent valve, EVAP canister purge valve, fuel sender assembly and/or seal, VTP sensor seal, fill limiter vent valve, pressure relief valve, rollover valves, permanent EVAP pipes and/or fuel tank. Repair as necessary. After repairs, go to step 19 . If no problem is found, see «DIAGNOSTIC AIDS»(ref-117480-S16153260912001082000000) .
9. Disconnect EVAP purge pipe from canister purge valve. Install vacuum hose from diagnostic station to the EVAP canister purge valve port. Operate engine at 1200-1500 RPM. Using scan tool, command EVAP canister purge valve to 50 percent. If EVAP diagnostic station vacuum gauge reading is greater than 12 in. Hg, see «DIAGNOSTIC AIDS»(ref-117480-S16153260912001082000000) . If EVAP diagnostic station vacuum gauge reading is not greater than 12 in. Hg, go to step 15 .
10. Monitor pressure gauge on EVAP diagnostic station. Disconnect EVAP purge pipe from EVAP canister purge valve. If EVAP system pressure decreases, go to step 16 . If EVAP system pressure does not decrease, go to next step.
11. Monitor pressure gauge on EVAP diagnostic station. Disconnect purge pipe at EVAP canister. If EVAP system pressure decreases, clean EVAP system. If EVAP system pressure does not decrease, go to next step.
12. Monitor pressure gauge on EVAP diagnostic station. Disconnect EVAP vapor line from EVAP canister. If EVAP system pressure decreases, go to step 17 . If EVAP system pressure does not decrease, go to step 14 .
13. Replace VTP sensor. After replacing sensor, go to step 18 .
14. Repair pinched or obstructed EVAP vapor pipe. After repairs, go to step 18 .
15. Check vacuum source to EVAP purge valve for blockage, cuts or disconnects. Repair as necessary. After repairs, go to step 18 . If no problem is found, go to next step.
16. Replace EVAP canister purge valve. After replacing purge valve, go to step 18 .
17. Replace EVAP canister. After replacing canister, go to next step.
18. Using scan tool, perform service bay check. If scan tool indicates that test passed, go to next step. If scan tool does not indicate that test passed, go to step 2 .
19. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for a malfunctioning or damage EVAP canister, a loose, missing, defective or incorrect fuel fill cap or an incorrectly routed, kinked, pinched, plugged, or defective EVAP system vacuum and vapor pipes. Check for charcoal release from EVAP canister. Remove any debris from connector surfaces before servicing a component. Check connector gaskets when diagnosing or replacing a component. Ensure gaskets are installed correctly.

Check for poor terminal connections, backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Observe scan tool display while moving connectors and wiring harnesses related to the sensor. A change in scan tool display may indicate the location of fault. Ensure PCM and engine grounds are clean and secured.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck for DTCs. If DTC P0443 or P0449 is also set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0443 or P0449 is not set, go to next step.
3. Check EVAP system for loose, missing or damaged service port Schrader valve. Check for loose, incorrect, missing or damaged fuel fill cap, or damaged EVAP canister purge valve. Raise vehicle on hoist. Check EVAP system for disconnected, improperly routed, kinked or damaged EVAP pipes and hoses. Check for damaged EVAP canister vent valve Repair as necessary. After repairs, go to step 6 . If no problem is found, go to next step.
4. Using scan tool, capture and record FREEZE FRAME/FAILURE RECORDS data and clear DTCs. Using scan tool, perform service bay check. If scan tool indicates that service bay test passed, see «DIAGNOSTIC AIDS»(ref-117480-S11869404192001082000000) . If scan tool does not indicate that service bay test passed, go to next step.
5. Connect Fill Tank Cap Adapter (J-41415-40) to fuel filler neck and fuel filler cap. Connect EVAP Pressure Diagnostic Station (J-41413) to adapter. Turn ignition on, with engine off. Using scan tool, seal EVAP system. Using EVAP diagnostic station, continuously pressurize EVAP system to 15 in. H2O. Using Ultrasonic Leak Detector (J-41416), check for leaks in EVAP system purge pipe, vapor pipe, vent hose, fuel fill pipe/hose, fuel fill cap, EVAP canister, EVAP canister vent valve, EVAP canister purge valve, fuel sender assembly and/or seal, VTP sensor, fill limiter vent valve, pressure relief valve, rollover valves, permanent EVAP pipes, and/or fuel tank. Repair as necessary. After repairs, go to next step. If no problem is found, see «DIAGNOSTIC AIDS»(ref-117480-S11869404192001082000000) .
6. Turn ignition on, with engine off. Using scan tool, perform Service Bay Check. If scan tool indicates that service bay check passed, go to next step. If scan tool does not indicate that service bay check passed, go to step 2 .
7. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Use the EVAP pressure/purge diagnostic station in order to pressurize the EVAP system to aid in locating intermittent leaks. Move all EVAP components while testing with Ultrasonic Leak Detector (J-41416).

Reviewing the FAIL RECORDS vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EVAP purge solenoid to 50 percent and then to zero percent. If clicking is heard or felt from EVAP purge solenoid when commanded to 50 percent, go to next step. If clicking is not heard or felt from EVAP purge valve, go to step 4 .
3. Review FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S21712425512001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Disconnect EVAP purge solenoid harness connector. Turn ignition on, with engine off. Using a test light connected to ground, probe EVAP purge solenoid harness connector terminal "A" (Pink wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
5. Connect test light between EVAP purge solenoid harness connector terminals "A" (Pink wire) and "B" (Dark Green/White wire). Using scan tool, command EVAP purge solenoid to 50 percent and then to zero percent. If test light turns on or pulses when solenoid is commanded to 50 percent, go to step 9 . If test light does not turn on or pulse when solenoid is commanded to 50 percent, 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. Check for open or short to voltage in Dark Green/White wire between EVAP purge solenoid harness connector terminal "B" and PCM harness connector C1 terminal No. 76. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 10 .
8. Turn ignition off. Check for a short to ground in Dark Green/White wire between EVAP purge solenoid harness connector terminal "B" and PCM harness connector C1 terminal No. 76. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 13 .
9. Turn ignition off. Check for poor connections EVAP purge solenoid harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
11. Turn ignition off. Repair EVAP purge solenoid ignition voltage circuit (Pink wire). After repairs, go to step 14 .
12. Replace EVAP purge solenoid. After replacing EVAP purge solenoid, go to step 14 .
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S21712425512001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
15. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

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.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck for DTCs. If DTC P0443, P0449, P0452 or P0453 is set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0443, P0449, P0452 or P0453 is not set, go to next step.
3. Check for damaged EVAP vent solenoid or pinched EVAP vent hose. Repair as necessary. After repairs, go to step 14 . If no problem is found, go to next step.
4. Disconnect EVAP purge valve purge line. Turn ignition on, with engine off. Observe Fuel Tank Pressure (FTP) parameter on scan tool. If scan tool indicates that FTP parameter is about zero in. H2O, go to next step. If scan tool does not indicate that FTP parameter is about zero in. H2O, go to step 8 .
5. Turn ignition off. Reconnect all previously disconnected hardware. Install Fuel Fill Cap Adapter (J-41415). Connect EVAP Pressure/Purge Diagnostic Station (J-41413) and fuel filler cap to fuel fill cap adapter. Turn ignition on, with engine off. Using scan tool, command EVAP canister vent valve on. DO NOT exceed the specified value in this step or test results will be incorrect. Pressurize EVAP system to 5 in. H2O using EVAP pressure/purge diagnostic station. Rotate rotary switch to OFF/HOLD position. Using scan tool, command EVAP canister vent valve off. If scan tool indicates that FTP parameter is about zero in. H2O, see «DIAGNOSTIC AIDS»(ref-117480-S11149736352001111000000) . If scan tool does not indicate that FTP parameter is about zero H2O, go to next step.
6. Disconnect EVAP canister vent hose from EVAP canister vent valve. If scan tool indicates that fuel tank pressure is within -0.5 to 0.5 in. H2O, go to step 10 . If scan tool does not indicate that fuel tank pressure is within -0.5 to 0.5 in. H2O, go to next step.
7. Disconnect EVAP vapor vent pipe from EVAP canister. If scan tool indicates fuel tank pressure parameter is about zero in. H2O, go to step 13 . If scan tool does not indicate fuel tank pressure parameter is about zero in. H2O, go to step 11 .
8. Using scan tool, observe FTP sensor voltage. If FTP sensor voltage is greater than 4.3 volts, go to «DTC P0453»(ref-117480-S35556477642001082000000) . If FTP sensor voltage is not greater than 4.3 volts, go to next step.
9. Check for poor connections at FTP sensor harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
10. Replace EVAP canister vent valve. After replacing canister vent valve, go to step 14 .
11. Replace EVAP canister. After replacing canister, go to step 14 .
12. Replace FTP sensor. After replacing sensor, go to step 14 .
13. Repair blockage in EVAP vent hose. After repairs, go to next step.
14. Turn ignition on, with engine off. Using scan tool, command EVAP canister vent valve on. DO NOT exceed 5 in. H2O in this step. Using EVAP diagnostic station, pressurize EVAP system to 5 in. H2O. Turn rotary valve to OFF/HOLD position. Monitor pressure gage on diagnostic station. Using scan tool, command EVAP canister vent valve off. If EVAP system pressure decreases, go to next step. If EVAP system pressure does not decrease, go to step 3 .
15. Using scan tool, select REVIEW INFO option. If any undiagnosed DTCs are displayed, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

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

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck DTCs. If DTC P0443, P0449, P0452 or P0453 is set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0443, P0449, P0452 or P0453 is not set, go to next step.
3. Check for damaged EVAP vent solenoid or pinched EVAP vent hose. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
4. Using scan tool, clear DTCs. Using scan tool, perform the service bay check. If scan tool indicates that test passed, see «DIAGNOSTIC AIDS»(ref-117480-S07831463552001082000000) . If scan tool does indicate that test passed, go to next step.
5. Disconnect purge line from EVAP purge solenoid. Turn ignition on, with engine off. Using scan tool, observe fuel tank pressure parameter. If scan tool indicates that fuel tank pressure is about zero in. H2O, go to next step. If scan tool does not indicate that fuel tank pressure is about zero in. H2O, go to step 10 .
6. Reconnect all previously disconnected hardware. Connect Fill Tank Cap Adapter (J-41415-40) to fuel filler neck and fuel filler cap. Connect EVAP Pressure Diagnostic Station (J-41413) to Adapter. Turn ignition on, with engine off. Using scan tool, seal EVAP system. Using EVAP diagnostic station, pressurize EVAP system to 5 in. H2O. Move rotary switch on diagnostic station to OFF/HOLD position. Disconnect EVAP vent hose from EVAP vent solenoid. If scan tool indicates fuel tank pressure at about zero in. H2O, go to step 8 . If scan tool does not indicate fuel tank pressure at about zero in. H2O, go to next step.
7. Disconnect EVAP vapor pipe from EVAP canister. If scan tool indicates fuel tank pressure at about zero in. H2O, go to step 11 . If scan tool does not indicate fuel tank pressure at about zero in. H2O, go to step 9 .
8. Replace EVAP vent solenoid. After replacing vent solenoid, go to step 12 .
9. Replace EVAP canister. After replacing canister, go to step 12 .
10. Replace FTP sensor. After replacing sensor, go to step 12 .
11. Repair for blockage in EVAP vent hose. After repairs, go to next step.
12. Reconnect all EVAP hardware that was previously disconnected. Using scan tool, perform service bay check. If scan tool indicates that service bay check passed, go to next step. If scan tool does not indicate that service bay check passed, go to step 3 .
13. Using scan tool, select REVIEW INFO option. If any undiagnosed DTCs are displayed, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

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

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EVAP vent valve on and off. If clicking is heard or felt from EVAP vent solenoid when commanded on and off, go to next step. If clicking is not heard or felt from EVAP vent solenoid, go to step 4 .
3. Using scan tool, review FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S04817231722001091700000) . If this DTC fails this ignition, go to next step. If this DTC does not fail this ignition, problem is intermittent.
4. Raise and support vehicle. Disconnect fuel tank harness connector at body pass-through connector. Using a test light connected to ground, probe EVAP vent solenoid connector terminal "A" (Pink wire) at body pass-through connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 13 .
5. Connect test light between EVAP vent solenoid harness connector terminals at body pass-through 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. Check for short to voltage or open in White wire between EVAP vent solenoid harness connector terminal "B" and PCM harness connector C2 terminal No. 2. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
8. Turn ignition off. Check for short to ground in White wire between EVAP vent solenoid harness connector terminal "B" and PCM harness connector C2 terminal No. 2. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
9. Turn ignition off. Check for poor connections at body pass-through connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
10. Remove fuel tank. Disconnect EVAP vent solenoid harness connector. Check EVAP vent solenoid jumper harness circuits for an open or short to ground. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to next step.
11. Check for poor connections at EVAP vent solenoid harness connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to step 14 .
12. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to step 15 .
13. Turn ignition off. Repair open or short to ground in EVAP vent solenoid ignition voltage circuit (Pink wire). After repairs, go to step 16 .
14. Replace EVAP vent solenoid. After replacing solenoid, go to step 16 .
15. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S04817231722001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
17. Using scan tool, review the stored information and CAPTURE INFO. If the scan tool display any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Operate engine at idle for one minute. Using scan tool, monitor DTC information. If DTC P1635 or P1639 is set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P1635 or P1639 is not set, go to next step.
3. Using scan tool, observe FTP sensor voltage. If scan tool indicates that FTP sensor voltage is less than 0.1 volt, go to step 5 . If FTP sensor voltage is not less than 0.1 volt, go to next step.
4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S34112807642001091700000) . If DTC fails this ignition, go to next step. If DTC does not reset, problem is intermittent.
5. Turn ignition off. Raise and support vehicle. Disconnect fuel tank wiring harness at the body pass-through connector. Connect a fused jumper wire between FTP sensor harness connector terminals "B" (Dark Green wire) and "C" (Gray/Black wire) at the body pass-through connector. Turn ignition on, with engine off. Using scan tool, observe FTP sensor voltage. If FTP sensor voltage is about 5 volts, go to step 8 . If FTP sensor is not about 5 volts, go to next step.
6. Turn ignition off. Check FTP sensor 5-volt reference circuit (Gray/Black wire) for short to ground or open between the body pass-through connector and PCM. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
7. Check FTP sensor signal circuit (Dark Green wire) for short to ground or open between the body pass-through connector and PCM. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
8. Turn ignition off. Remove fuel tank. Disconnect FTP sensor harness connector. Check fuel tank wiring harness for pinches, cuts, or internal breaks. Repair as necessary. After repairs, go to step 13 . If no problem is found, go to next step.
9. Check for poor connections at FTP sensor harness connector and fuel tank harness body pass-through connector. Repair as necessary. After repairs, go to step 13 . If no problem is found, go to step 11 .
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
11. Replace FTP sensor. After replacing sensor, go to step 13 .
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S34112807642001091700000) . If this DTC resets, go to step 2 . If this DTC does not reset, go to next step.
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnosed affected DTCs. If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Operate engine at idle for one minute. Using scan tool, monitor DTC information. If DTC P1635 or P1639 is set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P1635 or P1639 is not set, go to next step.
3. Turn ignition on, with engine off. Using scan tool, observe Fuel Tank Pressure (FTP) sensor voltage. If FTP sensor voltage is greater than 4.3 volts, go to step 5 . If FTP sensor voltage is not greater than 4.3 volts, go to next step.
4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S17449957972001091700000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
5. Turn ignition off. Raise and support vehicle. Disconnect fuel tank wiring harness at the body pass-through connector. Turn ignition on, with engine off. Using scan tool, observe FTP sensor voltage. If FTP sensor voltage is greater than zero volts, go to next step. If FTP sensor voltage is not greater than zero volts, go to step 7 .
6. Check FTP sensor signal circuit (Dark Green wire) for short to voltage between the body pass-through connector and PCM. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
7. Using a test light connected to battery voltage, probe FTP sensor low reference circuit (Black/White wire) at the body pass-through. If test light illuminates, go to step 9 . If test light does not illuminate, go to next step.
8. Turn ignition off. Check FTP sensor low reference circuit (Black/White wire) for open between the body pass-through connector and PCM. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
9. Turn ignition off. Remove fuel tank. Disconnect FTP sensor harness connector. Check fuel tank wiring harness for damage, poor connections or broken wires inside insulation. Repair as necessary. After repairs, go to step 13 . If no problem is found, go to step 11 .
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
11. Replace FTP sensor. After replacing sensor, go to step 13 .
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S17449957972001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe fuel level parameter in the PCM EVAP data list. If fuel level parameter is less than 3.5 percent, go to next step. If fuel level parameter is not less than 3.5 percent, see «DIAGNOSTIC AIDS»(ref-117480-S01316425542001082000000).
3. Turn ignition off. Disconnect fuel level sensor harness connector from fuel tank. Turn ignition on, with engine off. Using scan tool, observe fuel level parameter. If fuel level parameter is greater than 98 percent, go to step 5. If fuel level parameter is not greater than 98 percent, go to next step.
4. Turn ignition off. Check for short to ground in fuel level sensor harness connector terminal "A" (Purple wire). see scheme 2 Repair as necessary. After repairs, go to step 10. If circuit is okay, go to step 7.
5. Turn ignition off. Check fuel level sensor signal circuit (Black/White wire) for short to ground between body connector and fuel level sensor. Repair as necessary. After repairs, go to step 10. If circuit is okay, go to next step.
6. Check for poor connections at fuel level sensor harness connector. Repair as necessary. After repairs, go to step 10. If connections are okay, go to step 8.
7. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 10. If connections are okay, go to step 9.
8. Replace fuel level sensor. After replacing sensor, go to step 10.
9. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S32191297412001091700000). If DTC resets, go to step 2. If DTC does not reset, system is okay.

Use FREEZE FRAME/FAILURE RECORDS data in order to locate an intermittent condition. If DTC cannot be duplicated, the information included in FREEZE FRAME/FAILURE RECORDS data may aid in determining the number of miles since the DTC set. The FAIL COUNTER and PASS COUNTER can also aid in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate vehicle within the same FREEZE FRAME conditions (RPM, engine load, vehicle speed, temperature, etc.). This will isolate when DTC failed.

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.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe fuel level parameter in the PCM EVAP data list. If fuel level parameter is greater than 98 percent, go to next step. If fuel parameter is not greater than 98 percent, see «DIAGNOSTIC AIDS»(ref-117480-S10922200502001082000000).
3. Turn ignition off. Disconnect fuel level sensor harness connector. Connect a fused jumper wire between fuel level sensor harness connector terminals "A" (Purple wire) and "D" (Black wire). see scheme 2 Turn ignition on, with engine off. Using scan tool, observe fuel level parameter. If fuel level parameter is less than 3.5 percent, go to step 6. If fuel level parameter is not less than 3.5 percent, go to next step.
4. Turn ignition off. Check for open, high resistance, or short to voltage in Purple wire between fuel level sensor harness connector "A" and PCM harness connector C2 terminal No. 69. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to next step.
5. Check for open, high resistance, or short to voltage in Black wire between fuel level sensor harness connector "D" and PCM harness connector C2 terminal No. 35. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 9.
6. Turn ignition off. Check for open, high resistance, or short to voltage in Purple wire between the pass-through connector and fuel level sensor harness connector terminal "A". Repair as necessary. After repairs, go to step 12. If circuit is okay, go to next step.
7. Check for open, high resistance, or a short to voltage in Black wire between the pass-through connector and PCM harness connector C2 terminal No. 35. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to next step.
8. Check for poor connections at fuel level sensor harness connector. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 10.
9. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 11.
10. Replace fuel level sensor. After replacing sensor, go to step 12.
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
12. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S42362192032001091700000). If DTC resets, go to step 2. If DTC does not reset, system is okay.

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.

1. Perform engine cooling diagnostic system check. See appropriate ENGINE COOLING article in ENGINE, CLUTCHES & DRIVE AXLES. Repair as necessary. After performing engine cooling diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command the low speed fan on and off. If cooling fan 1 relay turns on and off with each command, see «DIAGNOSTIC AIDS»(ref-117480-S22675644132001082000000) . If cooling fan 1 relay does not turn in and off with each command, go to next step.
3. Turn ignition off. Remove cooling fan 1 relay (located in underhood fuse/relay block). Turn ignition on, with engine off. Using a test light connected to ground, probe cooling fan 1 relay battery voltage circuit in fuse/relay block. 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 control circuit (Dark Green wire) and battery voltage circuit in underhood fuse/relay block. Using scan tool, command low speed fan 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, go to next step.
5. If test light remains on with each command, go to step 7 . If test light does not remain on with each command, go to next step.
6. Turn ignition off. Check for short to voltage or open in Dark Green wire between underhood fuse/relay block terminal F3 and PCM harness connector C1 terminal No. 6. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 9 .
7. Turn ignition off. Check for short to ground in Dark Green wire between fuse/relay block terminal F3 and PCM harness connector C1 terminal No. 6. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 9 .
8. Turn ignition off. Check cooling fan relay 1 battery voltage circuit in fuse/relay block for short to ground or open circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 11 .
9. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
10. Turn ignition off. Check for poor connections at cooling fan 1 relay. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
11. Repair cooling fan motor supply voltage circuit for short to ground. After repairs, go to step 14 .
12. Replace cooling fan 1 relay. After replacing relay, go to step 14 .
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S07317143312001091700000) . If DTC resets, go to step 2 . If DTC does not reset, system is okay.

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.

Using FREEZE FRAME and/or FAILURE RECORDS data mode may aid in locating an intermittent condition. If DTC cannot be duplicated, information included in FREEZE FRAME and/or FAILURE RECORDS data can be useful in determining how many miles since DTC set. FAIL COUNTER and PASS COUNTER can also be used to determine how many ignition cycles diagnostic reported a pass or a fail condition. To isolate when DTC failed, operate vehicle within same freeze frame conditions (RPM, load, vehicle speed, temperature, etc.).

1. Perform engine cooling diagnostic system check. See appropriate ENGINE COOLING article in ENGINE, CLUTCHES & DRIVE AXLES. Repair as necessary. After performing engine cooling diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command high speed fan on and off. If cooling fan relay and cooling fan 2 relays turns on and off with each command, see «DIAGNOSTIC AIDS»(ref-117480-S33089395912001082000000). If relays does not turn on and off, go to next step.
3. Turn ignition off. Remove cooling fan 2 relay (located in underhood fuse/relay block). Turn ignition on, with engine off. Using a test light connected to ground, probe cooling fan relay 2 battery voltage circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 8.
4. Connect test light between high speed cooling fan 2 control circuit and battery voltage circuit in fuse/relay 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 on with each command, go to step 7. If test light does not remain on with each command, go to next step.
6. Turn ignition off. Check cooling fan relay and high speed cooling fan 2 relay control circuit (Dark Blue wire) to PCM harness connector C1 terminal No. 5 for short to voltage or open circuit. see scheme 4 Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 9.
7. Turn ignition off. Check cooling fan relay and high speed cooling fan 2 relay control circuit (Dark Blue wire) for short to ground. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 9.
8. Turn ignition off. Check cooling fan relay and cooling fan 2 relay battery voltage circuit in fuse/relay block for open or short to ground. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 10.
9. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 11.
10. Repair cooling fan motor supply voltage circuit (Light Blue wire) for short to ground. After repairs, go to step 12.
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
12. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S23028036872001091700000). If DTC resets, go to step 2. If DTC does not reset, system is okay.

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.

Using FREEZE FRAME and/or FAILURE RECORDS data mode may aid in locating an intermittent condition. If DTC cannot be duplicated, information included in FREEZE FRAME and/or FAILURE RECORDS data can be useful in determining how many miles since DTC set. FAIL COUNTER and PASS COUNTER can also be used to determine how many ignition cycles diagnostic reported a pass or a fail condition. To isolate when DTC failed, operate vehicle within same freeze frame conditions (RPM, load, vehicle speed, temperature, etc.).

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, read DTCs. If any other DTCs are set, diagnose affected DTCs before proceeding with test. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no other DTCs are set, go to next step.
3. Observe the FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S15877731192001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S20090599292001082000000).
4. Turn ignition off. Disconnect IAC valve harness 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. Command IAC valve out until about 1800 RPM is reached. Return engine speed to desired idle as indicated on scan tool data list. If engine speed steadily decreases to about 600 RPM and steadily increases to about 1800 RPM when IAC valve was commanded in and out, go to next step. If idle speed or engine RPM is not as specified, go to step 11.
5. Turn engine off. Install Connector Check Adapter Kit (J-35616-A) to IAC valve harness connector. Using a test light connected to ground, probe one of IAC valve circuits at IAC valve harness connector Adapter kit. Start engine. Using IAC motor driver, command low RPM while observing scan tool until the IAC counts start to increment. Command high RPM while observing a scan tool until IAC counts start to increment. While IAC counts are incrementing, observe test light. Return engine idle speed to desired idle as indicated on scan tool data list. Repeat procedure for the other 3 IAC valve circuits. If test light remains on (never flashing) while IAC counts were incrementing at any of the IAC valve circuits during the test, go to step 10. If test light does not remain on, go to next step.
6. If test light remains off (never flashing) while IAC counts where incrementing at any of the IAC valve circuits during the test, go to step 9. If test light does not remain off, go to next step.
7. Turn engine off. Using connector check Adapter kit, connect test light between IAC coil "A" harness connector terminals "C" (Light Blue/Black wire) and "D" (Light Blue/White wire). see scheme 10 Start engine. Using IAC motor driver, command low RPM while observing scan tool until IAC counts start to increment. Command high RPM while observing scan tool until IAC counts start to increment. While IAC counts are incrementing, observe test light. Return engine speed to desired RPM as indicated on scan tool data list. Repeat procedure with test light connected between IAC coil "B" harness connector terminals "A" (Light Green/Black wire) and "B" (Light Green/White wire). Return engine speed to desired idle as indicated on scan tool data list. If test light stays illuminated (never flashing) while IAC counts are incrementing during the test, go to next step. If test light does not stay illuminated, go to step 15.
8. Turn ignition off. Check for poor connection at IAC valve harness connector. Repair as necessary. After repairs, go to step 16. If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S20090599292001082000000).
9. Turn ignition off. Disconnect PCM harness connectors. Using DVOM, check for open or short to ground on IAC valve circuit where test light remained off. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
10. Using DVOM, check short to voltage on IAC valve circuit where test light remained illuminated. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
11. Check for throttle body damage and tampering. Check for restricted air intake system, collapsed/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. Check for clogged IAC passage, excessive deposits on throttle plate, throttle bore or IAC valve pintle. Repair as necessary. After repairs, go to step 16. If no problem is found, go to step 13.
12. Check for poor connection at PCM harness connectors. Repair as necessary. After repairs, go to step 16. If connections are okay, go to step 15.
13. Check for poor connection at IAC valve harness connector. Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
14. Replace IAC valve. After replacing IAC valve, go to step 16.
15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S15877731192001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
17. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connection at IAC and PCM connectors. Check for damaged harness. Check for restrictions, collapse or blockage in air intake system, air ducts or air filter. Check throttle body bore and IAC for excessive deposits. Check for large vacuum leak, such as incorrectly installed PCV valve or disconnected brake booster hose. Check for restricted air intake system.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Set parking brake and block drive wheels. Turn off all accessories. Using scan tool in RPM control function, slowly increment engine speed to 1800 RPM then to 600 RPM, then to 1800 RPM. Exit RPM control function. If engine speed stabilizes within 150 RPM of commanded RPM during the test, go to next step. If engine speed does not stabilize within 150 RPM of commanded RPM during test, go to step 4 .
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S42607554782001091700000) . If DTC fails this ignition, go to next step. If DTC does no fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S20677983302001082000000) .
4. Turn ignition off. Disconnect IAC valve harness 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. Command IAC valve out until about 1800 RPM is reached. Return engine speed to desired idle as indicated on scan tool data list. If engine speed steadily decreases to about 600 RPM and steadily increases to about 1800 RPM when IAC valve was commanded in and out, go to next step. If engine speed does not respond as specified, go to step 11 .
5. Turn ignition off. Connect Connector Check Adapter Kit (J-35616-A) to IAC valve harness connector. Using a test light connected to ground, probe one of the IAC valve circuits at connector check Adapter kit. Start engine. Using scan tool, command low RPM while observing a scan tool until IAC counts start to increment. Command high RPM while observing scan tool until IAC counts start to increment. While IAC counts are incrementing, observe test light. Return engine speed to desired RPM as indicated on scan tool data list. Repeat test for the other 3 IAC valve circuits. If test light remains on (never flashing) while IAC counts were incrementing at any of the IAC valve circuits during the test, go to step 10 . If IAC counts were not incrementing at any of the IAC valve circuit during the test, go to next step.
6. If test light remains off (never flashing) while IAC counts were incrementing at any of the IAC valve circuits during the test, go to step 9 . If test light does not remain off, go to next step.
7. Turn engine off. Using connector check Adapter kit, connect test light between IAC coil "A" harness connector terminals "C" (Light Blue/Black wire) and "D" (Light Blue/White wire). Start engine. Using IAC motor driver, command low RPM while observing scan tool until IAC counts start to increment. Command high RPM while observing scan tool until IAC counts start to increment. While IAC counts are incrementing, observe test light. Return engine speed to desired RPM as indicated on scan tool data list. Repeat procedure with test light connected between IAC coil "B" harness connector terminals "A" (Light Green/Black wire) and "B" (Light Green/White wire). Return engine speed to desired RPM as indicated on scan tool data list. If test light stays illuminated (never flashing) while IAC counts were incrementing during the test, go to next step. If test light does not remain illuminated, go to step 15 .
8. Turn ignition off. Check for poor connection at IAC valve harness connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S20677983302001082000000) .
9. Turn ignition off. Disconnect PCM harness connectors. Using DVOM, check for open or short to ground on IAC valve circuit where test light remained off. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
10. Turn ignition off. Using DVOM, check for short to voltage on IAC valve circuit where test light remained illuminated. Repair as necessary. After repairs, go to step 16 . If circuit is okay, go to step 12 .
11. Check for throttle body damage and tampering or throttle lever screw tampering, if equipped. Check for vacuum leaks, faulty or incorrectly installed PCV valve and hose, throttle shaft binding, or throttle linkage or cruise control linkage binding, if equipped Remove IAC valve. Check for debris in IAC passage, excessive deposits on throttle plate, throttle bore, or IAC valve pintle. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to step 13 .
12. Check for poor connection at PCM harness connectors. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to step 14 .
13. Check for poor connection at IAC valve harness connector. Repair as necessary. After repairs, go to step 16 . If connections are okay, go to next step.
14. Replace IAC valve. After replacing IAC valve, go to step 16 .
15. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
16. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S42607554782001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
17. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check IAC valve connector for proper connection. Check throttle linkage for signs of binding or excessive wear. A slow or unstable idle may be caused by one of the following

1. Improperly installed and improperly operating PCV valve.
2. Improper operation and installation of air intake components.
3. Improper installation and operation of MAF sensor, if equipped.
4. Tampered or damaged throttle stop screw, throttle plate, throttle shaft, throttle linkage, or cruise control linkage, if equipped.
5. Skewed TP sensor.
6. Excessive deposits in IAC passage or IAC pintle, throttle bore or throttle plate.
7. Excessive engine overloading.
8. Vacuum leaks.
9. A high or unstable idle condition could also be caused by a non-IAC system problem that cannot be overcome by IAC valve.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition off. Check A/C compressor for free rotation operation. Place HVAC control module in off position. Start engine. If A/C compressor engages, diagnose compressor clutch for not disengaging. If A/C compressor does not engage, go to next step.
3. Turn ignition on, with engine off. Using scan tool, observe A/C high side pressure parameter in PCM Engine Data 2 list. If scan tool indicates that A/C high side pressure parameter is 0.09-4.90 volts, problem is intermittent. If pressure parameter is not 0.09-4.90 volts, go to next step.
4. Turn ignition off. Disconnect A/C refrigerant pressure sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe A/C high side pressure parameter. If scan tool indicates that A/C high side pressure parameter is less than 0.09 volt, go to next step. If pressure parameter is not less than 0.09 volt, go to step 11 .
5. Turn ignition off. Connect a fused jumper wire between A/C refrigerant pressure sensor harness connector terminals "B" (Gray wire) and "C" (Red/Black wire). Turn ignition on, with engine off. Using scan tool, observe A/C high side pressure parameter. If pressure parameter is greater than 4.9 volts, go to next step. If pressure parameter is not greater than 4.9 volts, go to step 9 .
6. Disconnect jumper wire. Check voltage between A/C refrigerant pressure sensor harness connector terminals "A" (Black wire) and "B" (Gray wire). If voltage reading is less than 5.1 volts, go to next step. If voltage reading is not less than 5.1 volts, go to step 8 .
7. Turn ignition off. Disconnect battery negative cable. Check between chassis ground and A/C refrigerant pressure sensor harness connector terminal "A" (Black wire). If resistance is less than 5 ohms, go to step 13 . If resistance is not less than 5 ohms, go to step 12 .
8. Turn ignition off. Check for short to voltage in Gray wire between A/C refrigerant pressure sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 34. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
9. Turn ignition off. Check for short to ground, high resistance or open circuit in Gray wire between A/C refrigerant pressure sensor harness connector "B" and PCM harness connector C2 terminal No. 34. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to next step.
10. Check for short to ground, high resistance or open circuit in Red/Black wire between A/C refrigerant pressure sensor connector "C" and PCM harness connector C2 terminal No. 27. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
11. Turn ignition off. Check for short to voltage in Red/Black wire between A/C refrigerant pressure sensor connector "C" and PCM harness connector C2 terminal No. 27. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
12. Check for high resistance or open in Black wire between A/C refrigerant pressure sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 80. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
13. Check for poor connections at A/C refrigerant pressure sensor harness connector. Repair as necessary. After repairs, go to step 17 . If connections are okay, go to step 15 .
14. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 17 . If connections are okay, go to step 16 .
15. Replace A/C refrigerant pressure sensor. After replacing sensor, go to step 17 .
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S07061811982001091700000) . If DTC resets, go to step 3 . If DTC does not reset, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe ignition 1 signal parameter in PCM data list. If ignition 1 signal parameter is greater than 11 volts, go to step 6 . If ignition 1 signal parameter is not greater than 11 volts, go to next step.
3. Check battery voltage and compare voltage it with ignition 1 signal parameter in PCM data list. If voltages differ by more than 0.5 volt, go to next step. If voltages does not differ by more than 0.5 volt, diagnose charging system.
4. Turn ignition off. Check for high resistance in battery voltage supply circuit to PCM. Repair as necessary. After repairs, go to step 7 . If circuit is okay, go to next step.
5. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 7 . If connections are okay, go to next step.
6. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
7. Review and record the scan tool FAIL RECORDS data. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S16133619252001091700000) . Observe the Specific DTC Information for this DTC until the test runs. If DTC resets, go to step 2 . If DTC does not reset, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0602 is set, go to next step. If DTC P0602 is not set, go to step 5 .
3. Program PCM. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. Recheck for DTCs. If DTC P0602 resets, go to next step. If DTC P0602 is not set, go to step 6 .
4. Verify that all tool connections are secure. Verify the programming equipment is operating correctly and the correct software package and correct calibration package is used. Attempt to program the PCM. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. Recheck for DTCs. If DTC P0602 resets, go to next step. If DTC P0602 does not reset, go to step 6 .
5. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
6. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine. If scan tool displays any DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, go to next step.
7. Using scan tool, observe the stored information and Capture Info. If scan tool display any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to step 1 .

DTC indicates that contents of EEPROM have changed since PCM was programmed. The only possible repair is PCM replacement. Program replacement PCM with the latest and correct calibration for vehicle.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Program PCM with correct software. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. Recheck DTCs. If DTC resets, go to next step. If DTC does not reset, system is okay.
3. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to step 1 .

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn off all accessories, including headlights. Turn ignition on, with engine off. Using scan tool, observe ignition 1 signal parameter in PCM data list. If voltage parameter is greater than 13 volts, go to step 7 . If voltage parameter is not greater than 13 volts, go to next step.
3. Using scan tool, command GEN L-terminal on and off. If scan tool indicates that voltage level changes with each command, go to step 7 . If voltage level does not change with each command, go to next step.
4. Turn ignition off. Disconnect generator harness connector. Check voltage between a known-good ground and generator harness connector terminal "B" (Red wire). Using scan tool, command GEN L-terminal on and off. If voltage reading is zero volts with generator off and 5 volts with generator on, go to step 7 . If voltage reading is not as specified, go to next step.
5. Check generator turn on signal circuit (Red wire) for short to ground. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to step 7 .
6. Check for poor connections at generator harness connector. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to next step.
7. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to next step. If connections are okay, diagnose charging system.
8. Replace PCM. Program replacement PCM using required equipment. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
9. Using scan tool, review and record FAIL RECORDS data. Clear DTC. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S32799103162001091700000) . Using scan tool, observe SPECIFIC DTC information for this DTC and until test runs. If DTC resets, go to step 2 . If DTC does not reset, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command MIL on and off. If MIL turns on and off with each command, problem is intermittent. If MIL does not turn on and off, go to next step.
3. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. If MIL is off, go to next step. If MIL is on, go to step 5 .
4. Using a fused jumper wire connected to ground, jumper PCM harness connector C2 terminal No. 5 (Brown/White wire). If MIL illuminates, go to step 6 . If MIL does not illuminate, go to step 7 .
5. Repair short to ground in MIL control circuit (Brown/White wire). After repairs, go to step 9 .
6. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to step 8 .
7. Repair open in MIL ignition voltage circuit (Pink wire), or open or short to battery voltage in MIL control circuit (Brown/White wire). After repairs, go to step 9 .
8. Replace PCM. Program replacement PCM using required equipment. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate engine at idle and at normal operating temperature. Select DTC option and SPECIFIC DTC option, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If DTC resets, go to step 2 . If DTC does not reset, go to next step.
10. Select CAPTURE INFO option and REVIEW INFO option on scan tool. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, record FAILURE RECORDS data for reference, then clear DTCs. Using scan tool, observe TCC brake switch parameter. If scan tool displays CLOSED, problem is intermittent. If scan tool does not display CLOSED, go to next step.
3. Turn ignition off. Remove fuse from ignition 1 voltage circuit (fuse is located in underhood fuse/relay block). Check fuse. If fuse is open, go to next step. If fuse is okay, go to step 5 .
4. Repair short to ground in Pink wire between TCC brake switch and fuse block. After repairs, replace fuse, then go to step 10 .
5. Disconnect TCC brake switch harness connector. Connect fused jumper wire between TCC brake switch harness connector terminals "C" (Pink wire) and "D" (Purple wire). Turn ignition on, with engine off. Using scan tool, observe brake switch parameter. If scan tool displays CLOSED, go to step 8 . If scan tool does not display CLOSED, go to next step.
6. Check for open in Pink wire between fuse block and TCC brake switch. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
7. Check for open in Purple wire between PCM harness connector C1 terminal No. 30 and TCC brake switch harness connector terminal "D". Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 9 .
8. Replace TCC brake switch. After replacing switch, go to step 10 .
9. Replace PCM. Program replacement PCM using required equipment. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
10. Using scan tool, select DTC. Select CLEAR INFO. Turn ignition on, with engine off. TCC brake switch must display CLOSED (pedal released) for more than 2 seconds. Select SPECIFIC DTC. Enter DTC P0719. If test runs and passes, system is okay. If DTC resets, go to step 1 .

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, record FAILURE RECORDS. Clear DTCs. Using scan tool, observe TCC brake switch parameter while applying brake pedal. If scan tool displays OPEN, problem is intermittent. If scan tool does not display OPEN, go to next step.
3. Turn ignition off. Disconnect TCC brake harness connector. Turn ignition on, with engine off. Using scan tool, observe TCC brake switch parameter. If scan tool displays OPEN, go to step 5 . If scan tool does not display OPEN, go to next step.
4. Turn ignition off. Check for short power in Purple wire between PCM harness connector C1 terminal No. 30 and brake switch harness connector terminal "D". Repair as necessary. After repairs, go to step 7 . If circuit is okay, go to step 6 .
5. Turn ignition off. Replace TCC brake switch. After replacing switch, go to step 7 .
6. Replace PCM. Program replacement PCM using required equipment. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
7. Using scan tool, select DTC. Select CLEAR INFO. Turn ignition on, with engine off. Depress brake pedal. TCC brake switch must display OPEN for more than 2 seconds. Using scan tool, select SPECIFIC DTC, then enter DTC P0724. If DTC test runs and passes, system is okay. If DTC resets, go to step 1 .

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, monitor DTC information. If DTC P0108 or P1635 is set, diagnose affected DTCs first. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If DTC P0108 or P1635, go to next step.
3. If scan tool indicates that MAP sensor voltage is greater than 4.2 volts, go to step 5. If MAP sensor voltage is not greater than 4.2 volts, go to next step.
4. Using scan tool, observe MAP sensor voltage, while moving MAP sensor connector, PCM connector, and related wiring harness to MAP sensor. If scan tool indicates that MAP sensor voltage is greater than 4.2 volts and holding, go to next step. If MAP sensor voltage is not greater than 4.2 volts, see «DIAGNOSTIC AIDS»(ref-117480-S01320819472001082000000).
5. Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on, with engine off. If MAP sensor voltage is less than 0.1 volt, go to next step. If MAP sensor voltage is not less than 0.1 volt, go to step 8.
6. Using a DVOM, check voltage between MAP sensor harness connector terminals "A" (Orange/Black wire) and "C" (Gray wire). see scheme 5 If voltage reading is 4.7-5.2 volts, go to step 11. If voltage reading is not 4.7-5.2 volts, go to next step.
7. If voltage reading is greater than 5.2 volts, go to step 10. If voltage reading is not greater than 5.2 volts, go to step 9.
8. Turn ignition off. Check for short to voltage in Light Green wire between MAP sensor harness connector "B" and PCM harness connector C2 terminal No. 25. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 12.
9. Turn ignition off. Check for open in Orange/Black wire between MAP sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 13. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 12.
10. Turn ignition off. Check for short to voltage in Gray wire between MAP sensor harness connector terminal "C" and PCM harness connector C1 terminal No. 10. Repair as necessary. After repairs, go to step 13. If circuit is okay, go to step 12.
11. Turn ignition off. Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 13. If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S01320819472001082000000).
12. Check for poor connections at PCM. Repair as necessary. After repairs, go to next step. If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S01320819472001082000000).
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S10027187132001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Observe MAP display on scan tool while moving all related harnesses and connections. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, monitor DTC INFO. If DTC P0107 or P1635 is set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If DTC P0107 or P1635 is not set, go to next step.
3. Using scan tool, observe MAP sensor voltage. If voltage reading is less than 0.1 volt, go to step 5. If voltage reading is not 0.1 volt, go to next step.
4. Using scan tool, observe MAP sensor voltage, while moving MAP sensor connector, PCM connector and wiring harness related to MAP sensor. If MAP sensor voltage is less than 0.1 volt, go to next step. If MAP sensor voltage is not less than 0.1 volt, see «DIAGNOSTIC AIDS»(ref-117480-S21069787252001082000000).
5. Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on, with engine off. Check voltage between a known-good ground and MAP sensor harness connector terminal "C" (Gray wire). see scheme 5 If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 7.
6. Connect a fused jumper wire MAP sensor harness connector terminals "B" (Light Green wire) and "C" (Gray wire). If scan tool voltage reading is about 5 volts, go to step 9. If scan tool voltage reading is not about 5 volts, go to step 8.
7. Turn ignition off. Check for short to ground or open in Gray wire between MAP sensor harness connector terminal "C" and PCM harness connector C1 terminal No. 10. Repair as necessary. After repairs, go to step 11. If circuit is okay, go to step 10.
8. Turn ignition off. Check for short to ground or open in Light Green wire between MAP sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 25. Repair as necessary. After repairs, go to step 11. If circuit is okay, go to step 10.
9. Turn ignition off. Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 11. If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S21069787252001082000000).
10. Check for poor connections at PCM. Repair as necessary. After repairs, go to next step. If connections are okay, see «DIAGNOSTIC AIDS»(ref-117480-S21069787252001082000000).
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S25597550882001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
12. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check MAP sensor vacuum source for leaks, for restrictions or for poor connections. Observe MAP display on scan tool MAP while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, select DTC. If DTC P0113 is also set, go to «DTC P0113»(ref-117480-S16727731662001082000000) . If DTC P0113 is not set, go to next step.
3. If DTC P1106, P1115 and/or P1121 also set, go to step 6 . If DTC P1106, P1115 or P1121 is not set, go to next step.
4. Turn ignition off. Check for faulty connection at IAT sensor harness connector terminal "A" (Black wire). Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
5. Check for faulty connection at IAT sensor harness connector terminal "A" (Tan wire). Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
6. Turn ignition off. Check for intermittent open in Tan wire between IAT sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 50. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
7. Check for intermittent short to voltage in Tan wire between IAT sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 50. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to next step.
8. Check for a faulty sensor at PCM harness connector C1 terminal No. 17 (Black wire). Repair as necessary. After repairs, go to step 10 . If connection is okay, go to next step.
9. Check for intermittent open or faulty splice at Black wire between IAT sensor harness connector "A" and PCM harness connector C1 terminal No. 17. Repair as necessary. After repairs, go to next step. If connections are okay, problem is intermittent.
10. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the Failure Record conditions as noted. If DTC resets, go to step 2 . If DTC does not reset, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, select DTCs. If DTC P0112 is also set, go to «DTC P0112»(ref-117480-S30256001182001082000000). If DTC P0112 is not set, go to next step.
3. Turn ignition off. Check for short to ground in Tan wire between IAT sensor harness connector terminal "B" and PCM harness connector C2 terminal No. 50. see scheme 4 Repair as necessary. After repairs, go to next step. If circuit is okay, problem is intermittent.
4. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the FAILURE RECORD condition. If DTC resets, go to step 2. If DTC does not reset, system is okay.

Check for faulty connections or damaged harness. Observe IAT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on. Using scan tool, recheck DTCs. If DTC P0117 is also set, go to «DTC P0117»(ref-117480-S10457940202001082000000) . If DTC P0117 is not set, go to next step.
3. Using scan tool, observe ECT sensor temperature while moving sensor connector and PCM connector. If scan tool indicates an abrupt change in value, go to step 6 . If scan tool does not indicate an abrupt change in value, go to next step.
4. Using scan tool, observe ECT sensor temperature while moving wiring harness at ECT sensor and PCM connector. If scan tool indicates an abrupt change in value, go to step 7 . If scan tool does not indicate an abrupt change in value, go to next step.
5. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S35345060112001091700000) . If DTC resets, see «DIAGNOSTIC AIDS»(ref-117480-S40534525452001082000000) . If DTC does not reset, system is okay.
6. Turn ignition off. Repair connector/terminal as necessary. After repairs, go to step 8 .
7. Turn ignition off. Repair harness/wiring as necessary. After repairs, go to next step.
8. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S35345060112001091700000) . If DTC resets, go to step 2 . If DTC does not reset, go to next step.
9. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Observe ECT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, recheck for DTCs. If DTC P0118 is also set, go to «DTC P0118»(ref-117480-S39210876762001082000000) . If DTC P0118 is not set, go to next step.
3. Using scan tool, observe ECT sensor temperature while moving ECT sensor connector and PCM connector. If scan tool indicates an abrupt change in value, go to step 6 . If scan tool does not indicate an abrupt change in value, go to next step.
4. Using scan tool, observe ECT sensor temperature while moving wiring harness at sensor and PCM. If scan tool indicates an abrupt change in value, go to step 7 . If scan tool does not indicate an abrupt change, go to next step.
5. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S19122623222001091700000) . If DTC reset, see «DIAGNOSTIC AIDS»(ref-117480-S41894820962001082000000) . If DTC does not reset, system is okay.
6. Turn ignition off. Repair connector/terminal as necessary. After repairs, go to step 8 .
7. Turn ignition off. Repair harness/wiring as necessary. After repairs, go to next step.
8. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S19122623222001091700000) . If DTC resets, go to step 2 . If DTC does not reset, go to next step.
9. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Observe ECT display on scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location. Check for skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition off. Disconnect TP sensor harness connector. Connect a DVOM between TP sensor 5-volt reference circuit at TP sensor harness connector terminal "A" (Gray wire) and ground. see scheme 6 Turn ignition on, with engine off. Lightly touch and move related engine wiring harnesses and connectors for all 5 volt reference circuits while observing voltage. Any change in voltage indicates the area where a short to voltage may be found. Repair as necessary. After repairs, go to step 9. If circuits are okay, go to next step.
3. Turn ignition off. Connect DVOM between TP sensor signal circuit at TP sensor harness connector terminal "C" (Dark Blue wire) and ground. Turn ignition on, with engine off. Lightly touch and move related engine wiring harnesses and connectors while observing voltage. Any change in voltage indicates the area where a short to voltage may be found. Repair as necessary. After repairs, go to step 9. If circuits are okay, go to next step.
4. Turn ignition off for 30 seconds. Connect DVOM between TP sensor low reference circuit at TP sensor harness connector terminal "B" (Black wire) and ground. Lightly touch and move related engine wiring harnesses and connectors while observing resistance. Any change in resistance indicates the area where an open or high resistance may be found. Repair as necessary. After repairs, go to step 9. If circuits are okay, go to next step.
5. Check for poor connections at TP sensor harness connector. Repair as necessary. After repairs, go to step 9. If connections are okay, go to next step.
6. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 9. If connections are okay, go to next step.
7. Connect jumper wires to TP harness connector terminals "A" (Gray wire) and "C" (Dark/Blue wire). Set DVOM to 40K ohms scale. Connect DVOM between a known-good ground and jumper wires. Press the MIN MAX button on DVOM. Slowly depress accelerator pedal to Wide Open Throttle (WOT) positions and back to closed throttle position several times. Press the MIN MAX button on DVOM and record the MAX reading. Press MIN MAX button again and record MIN reading. Remove jumper wire from TP sensor harness connector terminal "A" (5-volt reference) and connect jumper to TP sensor harness connector terminal "B" (Black wire). Repeat steps 2 - 7. If MAX value is OL or MIN value is zero ohms in either test, go to next step. If MAX value is not OL or MIN value is not zero ohms in either test, problem is intermittent.
8. Replace TP sensor. After replacing sensor, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S27866109222001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
10. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition off. Disconnect TP sensor harness connector. Connect a DVOM between TP sensor 5-volt reference circuit at TP sensor harness connector terminal "A" (Gray wire) and chassis ground. see scheme 6 Turn ignition on, with engine off. Lightly touch and move related engine wiring harnesses and connectors for all 5-volt reference circuits while observing voltage. Any change in voltage indicates the area where a 5-volt reference circuit fault may be found. Repair as necessary. After repairs, go to step 8. If circuits are okay, go to next step.
3. Turn ignition off. Reconnect TP sensor harness connector. Turn ignition on, with engine off. Using scan tool, observe TP voltage parameter. Lightly touch and move the related engine wiring harnesses and connectors for the TP signal circuit while observing voltage. Any change in voltage indicates the area where a TP signal circuit fault may be found. Repair as necessary. After repairs, go to step 8. If circuit is okay, go to next step.
4. Turn ignition off. Check for poor connections at TP sensor harness connector. Repair as necessary. After repairs, go to step 8. If connections are okay, go to next step.
5. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 8. If connections are okay, go to next step.
6. Disconnect TP sensor harness connector. Connect jumper wires to TP sensor harness connector terminals "B" (Gray wire) and "C" (Red/Black wire). Set DVOM to 40K ohms scale. Connect DVOM to jumper wires. Press the MIN MAX button on DVOM. Slowly depress accelerator pedal to Wide Open Throttle (WOT) and back to closed throttle position several times. Press the MIN MAX button and record the MAX reading. Press the MIN MAX button again and record the MIN reading. Remove jumper wire at TP sensor harness connector terminal "B" and connect it terminal "A" (Black wire) and repeat steps 2 - 6. If MAX value is OL or MIN value is zero ohms in either test, go to next step. If MAX value is not OL or MIN value is not zero ohms in either test, problem is intermittent.
7. Replace TP sensor. After replacing sensor, go to next step.
8. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S38508851562001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
9. Using scan tool, observe the stored information and CAPTURED INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, clear DTCs and reset fuel trim values. Warm engine to normal operating temperature. Monitor HO2S No. 1 voltage on scan tool. If HO2S 1 voltage remains fixed within 300-600 millivolts, go to step 4. If voltage does not remain fixed within 300-600 millivolts, go to next step.
3. DTC may have been set by HO2S 1 connector water intrusion, HO2S 1 circuits with intermittent open or high resistance to ground, PCM ground circuits with high resistance, faulty HO2S 1, faulty PCM connector terminal contact, exhaust system leak (typically within 12 inches upstream of HO2S 1), or defective HO2S 1. Repair as necessary. After repairs, go to step 11. If no problem is found, problem is intermittent.
4. Turn ignition off. Disconnect HO2S 1 harness connector. Connect a jumper wire between a known-good ground and HO2S 1 harness connector terminal "A" (Tan wire). see scheme 2 Connect another jumper wire between a known-good ground and HO2S 1 harness connector terminal "B" (Purple wire). Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If voltage reading is less than 20 millivolts, go to step 8. If voltage reading is not less than 20 millivolts, go to next step.
5. Remove jumper wires from HO2S 1 harness connector terminals. Disconnect PCM harness connectors. Using DVOM, check continuity of Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10. Check continuity of Tan wire between HO2S 1 harness connector terminal "A" and PCM harness connector C1 terminal No. 12. If resistance of both circuits are less than 5 ohms, go to next step. If resistance of both circuits are less than 5 ohms, go to step 7.
6. Turn ignition off. Check for proper PCM connector terminal contact. Repair as necessary. After repairs, go to step 11. If terminals are okay, go to step 10.
7. Turn ignition off. Repair high resistance between HO2S 1 low reference circuit (Tan wire) and PCM ground circuit. After repairs, go to step 11.
8. Turn ignition off. Check for exhaust system leaks upstream of HO2S 1. The leak may be very small and typically will be within 12 inches of HO2S. Repair as necessary. After repairs, go to step 11. If no problem is found, go to next step.
9. Replace HO2S 1. After replacing sensor, go to step 11.
10. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S08455025882001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
12. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Ensure engine is at normal operating temperature. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S23362713072001091700000) . Using scan tool, observe SPECIFIC DTC INFO for DTC 1134 until DTC P1134 test runs. If DTC resets, go to next step. If DTC does not reset, problem is intermittent.
3. Check for an exhaust leak. Turn ignition off. Check for damaged wiring or HO2S 1 not installed correctly. Repair as necessary. After repairs, go to step 11 . If no problem is found, go to next step.
4. Check for corrosion on HO2S 1 terminals. Check for proper terminal tension at HO2S 1 and PCM. Repair as necessary. After repairs, go to step 8 . If no problem is found, go to next step.
5. Turn ignition off. Disconnect HO2S 1 harness connector. Connect jumper wire between a ground and HO2S 1 harness connector terminal "A" (Tan wire). Turn ignition on, with engine off. Using scan tool, observe HO2S 1 voltage. If voltage reading is about 450 millivolts, go to next step. If voltage reading is not about 450 millivolts, go to step 9 .
6. Jumper HO2S 1 harness connector terminals "A" (Tan wire) and "B" (Purple wire) to a known-good ground. Using scan tool, observe HO2S 1 voltage. If voltage reading is less than 300 millivolts, go to next step. If voltage reading is not less than 300 millivolts, go to step 10 .
7. Check for fuel contamination, excessive engine oil or coolant consumption, or improper use of RTV sealant. Repair cause of contamination, then replace HO2S 1 sensor. After replacing sensor, go to step 11 .
8. Repair as necessary. After repairs, go to step 11 .
9. Turn ignition off. Repair open in Tan wire between HO2S 1 harness connector terminal "A" and PCM harness connector C1 terminal No. 12 or grounded Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10. After repairs, go to step 11 .
10. Turn ignition off. Repair open in Purple wire between HO2S 1 harness connector terminal "B" and PCM harness connector C2 terminal No. 10 or poor connections at PCM. After repairs, go to next step.
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S23362713072001091700000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
12. Using scan tool, observe the stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe engine oil pressure parameter in the PCM IPC data list. If engine oil pressure parameter displays OK, problem is intermittent. If engine oil pressure parameter does not display OK, go to next step.
3. Disconnect engine oil pressure switch harness connector. Connect a fused jumper between engine oil pressure switch harness connector terminal and a good ground. Using scan tool, observe engine oil pressure parameter in the PCM IPC data list. If engine oil pressure parameter displays LOW, go to step 6 . If engine oil pressure parameter does not display LOW, go to next step.
4. Turn ignition off. Check Black/White wire between engine oil pressure switch and PCM for open, high resistance, or short to voltage. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
5. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to step 8 .
6. Turn ignition off. Check for poor connections at engine oil pressure switch. Repair as necessary. After repairs, go to step 9 . If connections are okay, go to next step.
7. Replace engine oil pressure switch. After replacing switch, go to step 9 .
8. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repairs, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S15541318592001091700000) . If DTC resets, go to step 2 . If DTC does not reset, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Perform crankshaft position system variation learn procedure. See «CRANKSHAFT POSITION SENSOR SYSTEM VARIATION LEARN PROCEDURE»(ref-117480-S19171613592001082000000) under PROGRAMMING.

The crankshaft position system variation compensating values are stored in the PCM's non-volatile memory after a learn procedure has been performed. If actual crankshaft position variation is not within the crankshaft position system variation compensating values stored in the PCM, DTC P0300 may set.

If crankshaft position system variation learn procedure cannot be performed successfully, check the following conditions and correct as necessary

1. Engine coolant temperature is less than 158°F (70°C).
2. Allow engine to warm-up to greater than 158°F (70°C).
3. PCM related DTCs set.
4. Scan tool crankshaft position system variation learn function will be disabled of any PCM DTCs other than DTC P1336 are stored.
5. Camshaft position signal problem detected.
6. 3X reference signal problem detected.
7. 24X reference signal problem detected.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe the FREEZE FRAME and/or FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME and/or FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S06725420502001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Turn ignition off. Disconnect PCM harness connector. Using a DVOM, check resistance between PCM harness connector C1, terminals No. 48 (Red/Black wire) and No. 54 (White wire). see scheme 4 If resistance is less than 500 ohms, go to step 5. If resistance is not less than 500 ohms, go to next step.
4. Disconnect IC module harness connector. Check for open in IC module circuits to PCM. Repair as necessary. After repairs, go to step 9. If circuits are okay, go to step 6.
5. Check for poor terminal connections at PCM. Repair as necessary. After repairs, go to step 9. If connections are okay, go to step 8.
6. Check for poor terminal connections at IC module. Repair as necessary. After repairs, go to step 9. If connections are okay, go to next step.
7. Replace IC module. After replacing IC module, go to step 9.
8. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
9. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S06725420502001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
10. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S16468311452001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using a test light connected to battery voltage, probe PCM harness connector C1 terminal No. 48 (Red/Black wire). see scheme 4 If test light illuminates, go to step 6. If test light does not illuminate, go to next step.
4. Turn ignition off. Check for open in Red/Black wire between IC module harness connector terminal "F" and PCM harness connector C1 terminal No. 48. see scheme 4and see scheme 11. Repair as necessary. After repairs, go to step 6. If circuit is okay, go to next step.
5. Check poor connections at IC module. Repair as necessary. After repairs, go to next step. If connections are okay, go to step 7.
6. Connect DVOM between PCM harness connector C1, terminals No. 48 (Red/Black wire) and No. 54 (White wire). Turn ignition on. Using a test light connected to battery voltage, probe PCM harness connector C1 terminal No. 53 (Tan/Black wire). Observe DVOM. If DVOM reads 5000 ohms, go to step 8. If DVOM does not read 5000 ohms, go to next step.
7. Turn ignition off. Leave PCM disconnected. Disconnect IC module harness connector. Check open in White wire between IC module harness connector terminal "B" and PCM harness connector C1 terminal No. 54. Repair as necessary. After repairs, go to step 12. If circuit is okay, go to step 9.
8. Turn ignition off. Inspect for poor terminal connections at PCM. Repair as necessary. After repairs, go to step 12. If connections are okay, go to step 11.
9. Inspect for poor terminal connections at IC module. Repair as necessary. After repairs, go to step 12. If connections are okay, go to next step.
10. Replace IC module. After replacing IC module, go to step 12.
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
12. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S16468311452001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
13. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Engine will start and may run in by-pass mode timing. If condition is intermittent, check for faulty connections or damaged harness. If connections and harness appear okay, observe scan tool while moving all related harnesses and connectors. A change in scan tool display indicates fault location.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, monitor DTC information. If DTC P1362 is also set, go to step 6. If DTC P1362 is not set, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S30499242092001091700000). If this DTC fails this ignition, go to next step. If this DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using a test light connected to ground, probe PCM harness connector C1 terminal No. 54 (White wire). see scheme 4 If test light illuminates, go to next step. If test light does not illuminate, go to step 14.
5. Turn ignition off. Leave PCM harness connector disconnected. Disconnect IC module harness connector. Turn ignition on. Using test light connected to ground, probe PCM harness connector C1 terminal No. 54 (White wire). If test light illuminates, go to step 10. If test light does not illuminate, go to step 13.
6. Turn ignition off. Disconnect PCM harness connector. Disconnect IC module harness connector. Using test light connected to battery voltage, probe PCM harness connector C1 terminal No. 54 (White wire). If test light illuminates, go to step 11. If test light does not illuminate, go to next step.
7. Leave ignition off, PCM harness connector disconnected, and IC module disconnected. With test light connected to battery voltage, probe PCM harness connector C1 terminal No. 53 (Tan/Black wire). see scheme 4 If test light illuminates, go to step 12. If test light does not illuminate, go to next step.
8. Check for short between the Tan/Black and White wires at the PCM harness connector and IC module harness connector. Repair as necessary. After repairs, go to step 15. If circuits are okay, go to next step.
9. Reconnect IC module harness connector. Leave PCM harness connector disconnected. Turn ignition on. Using a DVOM, check resistance between a known-good ground and PCM harness connector C1 terminal No. 54 (White wire) while probing PCM harness connector C1 terminal No. 53 (Tan/Black wire) with a test light connected to battery voltage. If resistance toggles between 100-600 ohms to 6000-10,000 ohms, go to step 14. If resistance does not toggle between 100-600 ohms to 6000-10,000 ohms, go to step 13.
10. Turn ignition off. Repair short to voltage in White wire between PCM harness connector C1 terminal No. 54 and IC module harness connector terminal "B". After repairs, go to step 15.
11. Repair short to ground in White wire between PCM harness connector C1 terminal No. 54 and IC module harness connector terminal "B". After repairs, go to step 15.
12. Repair short to ground in Tan/Black wire between PCM harness connector C1 terminal No. 53 and IC module harness connector terminal "A". After repairs, go to step 15.
13. Turn ignition off. Replace IC module. After replacing IC module, go to step 15.
14. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
15. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S30499242092001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 3.
16. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, monitor DTC information. If DTC P1361 is also set, go to step 6. If DTC P1361 is not set, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S03793635442001091700000). If this DTC fails this ignition, go to next step. If this DTC does not fail this ignition, problem is intermittent.
4. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using a test light connected to ground, probe PCM harness connector C1 terminal No. 54 (White wire). see scheme 4 If test light illuminates, go to next step. If test light does not illuminate, go to step 14.
5. Turn ignition off. Leave PCM harness connector disconnected. Disconnect IC module harness connector. Turn ignition on. Using test light connected to ground, probe PCM harness connector C1 terminal No. 54 (White wire). If test light illuminates, go to step 10. If test light does not illuminate, go to step 13.
6. Turn ignition off. Disconnect PCM harness connector. Disconnect IC module harness connector. Using test light connected to battery voltage, probe PCM harness connector C1 terminal No. 54 (White wire). If test light illuminates, go to step 11. If test light does not illuminate, go to next step.
7. Leave ignition off, PCM harness connector disconnected, and IC module disconnected. With test light connected to battery voltage, probe PCM harness connector C1 terminal No. 53 (Tan/Black wire). see scheme 4 If test light illuminates, go to step 12. If test light does not illuminate, go to next step.
8. Check for short between the Tan/Black and White wires at the PCM harness connector and IC module harness connector. Repair as necessary. After repairs, go to step 15. If circuits are okay, go to next step.
9. Reconnect IC module harness connector. Leave PCM harness connector disconnected. Turn ignition on. Using a DVOM, check resistance between a known-good ground and PCM harness connector C1 terminal No. 54 (White wire) while probing PCM harness connector C1 terminal No. 53 (Tan/Black wire) with a test light connected to battery voltage. If resistance toggles between 100-600 ohms to 6000-10,000 ohms, go to step 14. If resistance does not toggle between 100-600 ohms to 6000-10,000 ohms, go to step 13.
10. Turn ignition off. Repair short to voltage in White wire between PCM harness connector C1 terminal No. 54 and IC module harness connector terminal "B". After repairs, go to step 15.
11. Repair short to ground in White wire between PCM harness connector C1 terminal No. 54 and IC module harness connector terminal "B". After repairs, go to step 15.
12. Turn ignition off. Repair short to ground in Tan/Black wire between PCM harness connector C1 terminal No. 53 and IC module harness connector terminal "A". After repairs, go to step 15.
13. Replace IC module. After replacing IC module, go to step 15.
14. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
15. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S03793635442001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 3.
16. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start or starts but does not continue to run, see appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S32462685442001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S04583630202001082000000).
4. Turn ignition off. Disconnect IC module harness connector. Install an Injector Harness Load Tester (J-34730-380), using a load tester adapter to the multi-way fuel injector harness connector. Turn ignition on. Connect a test light to battery voltage. Repeatedly touch the test light to the IC module harness connector terminal "E" (Purple/White wire) while observing the load tester. see scheme 11 If load tester light blinks, go to step 8. If load tester light does not blink, go to next step.
5. Turn ignition off. Disconnect PCM harness connector. Check Purple/White wire between IC module harness connector terminal "E" and PCM harness connector C1 terminal No. 8 for open, shorted to ground or shorted to voltage. Repair as necessary. After repairs, go to step 11. If circuit is okay, go to next step.
6. Check for poor terminal connection at PCM harness connector C1 terminal No. 8 (Purple/White wire). Repair as necessary. After repairs, go to step 11. If terminal connection is okay, go to next step.
7. Check for incorrect harness routing near secondary ignition components. Check ignition coil arcing to wiring harness or IC module. Check ignition coils for cracks, carbon tracking or other signs of damage. Check secondary ignition wires arcing to wiring harness. Repair or replace as necessary. After repairs, go to step 11. If no problem is found, go to step 10.
8. Turn ignition off. Check for faulty terminal connections at IC module. Repair as necessary. After repairs, go to step 11. If connections are okay, go to next step.
9. Replace IC module. After replacing IC module, go to step 11.
10. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S32462685442001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
12. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for faulty connections or damaged harness. Observe a DVOM connected to 3X reference circuit at PCM harness connector while moving all related harnesses and connectors. A change in voltage indicates fault location.

Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for secondary ignition wire(s) arcing to wiring harness.

Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, diagnose ABS/TCS system. See appropriate ANTI-LOCK article in BRAKES.

If this DTC is set, it indicates that the ABS/TCS system has detected a malfunction which will not allow the EBCM to transmit correct rough data to PCM. Diagnose ABS system. See appropriate ANTI-LOCK article in BRAKES.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on. Using scan tool, select chassis application. Attempt to display ABS data on scan tool. If ABS data be displayed, go to next step. If ABS data cannot be displayed, go to step 4 .
3. Check serial data circuit for open or poor connection between PCM and EBCM. See WIRING DIAGRAMS article. Repair as necessary. Recheck for DTCs. If no DTCs are displayed, system is okay. If DTCs are displayed, see «DIAGNOSTIC AIDS»(ref-117480-S04585534422001090800000) .
4. Turn ignition off. Disconnect EBCM harness connector (located behind left side of dash, near steering column). Turn ignition on. Using a DVOM, check between ground and EBCM harness connector terminal C8 (Light Blue wire). If voltage varies within 1-5 volts, go to next step. If voltage does not vary within 1-5 volts, go to step 6 .
5. Turn ignition off. Check for poor connection at EBCM harness connector. Repair as necessary. After repairs, go to step 7 . If connections are okay, go to next step.
6. Turn ignition off. Check for open in Light Blue wire to EBCM. Repair as necessary. Reconnect EBCM harness connector. After repairs, go to next step. If circuit is okay, diagnose ABS system. See appropriate ANTI-LOCK article in BRAKES.
7. Turn ignition on. Using scan tool, attempt to display ABS data. If ABS data can be displayed and if no DTCs are displayed, system is okay. If ABS data cannot be displayed, go to step 4 .

Setting of this DTC indicates that a misfire was detected and that PCM could not determine if fault was a true misfire or was due to operating vehicle on rough surface. A misfire can be a true misfire with or without setting this DTC. Check PCM or EBCM for poor connections.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0403 is set, diagnose DTC P0403 first. See «DTC P0403»(ref-117480-S24492608462001082000000). Using scan tool, observe EGR position sensor parameter. If EGR position sensor parameter is at zero percent, go to next step. If EGR position sensor parameter is not at zero percent, go to step 5.
3. Turn ignition on, with engine off. Using scan tool, command EGR valve from 0-100 percent. If desired EGR position remains within 15 percent of EGR position sensor at all commanded positions, go to next step. If desired EGR position does not remain within 15 percent of EGR position sensor at all commanded positions, go to step 6.
4. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S39955703172001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, see «DIAGNOSTIC AIDS»(ref-117480-S26111460592001082000000).
5. Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, with engine off. Using scan tool, observe EGR position sensor parameter. If EGR position sensor is at zero percent, go to next step. If EGR position sensor is not at zero percent, go to step 9.
6. Using a DVOM, check voltage between EGR harness connector terminals "B" (Black wire) and "D" (Gray wire). see scheme 9 If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 8.
7. Connect a fused jumper wire between EGR harness connector terminals "C" (Brown wire) and "D" (Gray wire). If scan tool indicates that EGR position sensor value is about 100 percent, go to step 13. If scan tool does not indicate that EGR position sensor value is about 100 percent, go to step 11.
8. Check voltage between ground and EGR harness connector terminal "D" (Gray wire). If voltage reading is about 5 volts, go to step 10. If voltage reading is not about 5 volts, go to step 12.
9. Turn ignition off. Check for short to voltage in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 14.
10. Turn ignition off. Check for open or high resistance in Black wire between EGR harness connector terminal "B" and PCM harness connector C1 terminal No. 31. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 14.
11. Turn ignition off. Check for high resistance or short to ground in Brown wire between EGR harness connector terminal "C" and PCM harness connector C2 terminal No. 28. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 14.
12. Turn ignition off. Check for open, short to ground, or short to voltage in Gray wire between EGR harness connector terminal "D" and PCM harness connector C2 terminal No. 30. Repair as necessary. After repairs, go to step 17. If circuit is okay, go to step 14.
13. Turn ignition off. Check for poor connections at EGR valve harness connector. Repair as necessary. After repairs, go to step 17. If connections are okay, go to step 15.
14. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 17. If connections are okay, go to step 16.
15. Replace EGR valve. After replacing EGR valve, go to step 17.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S39955703172001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
18. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

Check for excessive deposits on EGR valve pintle or seat, causing EGR valve to stick. Check for poor connections at EGR and PCM connector. Check for faulty terminal connections or damaged harness.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Using scan tool, recheck DTCs. If DTCs P0443, P0449, P0452 or P0453 is also set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTCS P0443, P0449, P0452 or P0453 is not set, go to next step.
3. Turn ignition off. Remove fuel fill cap. Turn ignition on, with engine off. Using scan tool, monitor FTP sensor. If scan tool indicates FTP sensor is within -0.5 to 0.5 in. H2O, go to next step. If scan tool does not indicate that FTP sensor is within -0.5 to 0.5 in. H2O, go to «DTC P0453»(ref-117480-S35556477642001082000000) .
4. Turn ignition off. Disconnect purge pipe from EVAP canister purge valve. Install a hand-held vacuum gauge to EVAP canister purge valve purge port. Disconnect EVAP canister purge valve harness connector. Monitor vacuum on vacuum gage. Start and operate engine at idle. Increase engine speed to 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-117480-S02035153032001111200000) .
5. Turn ignition on, with engine off. Using scan tool, review and record FREEZE FRAME/FAILURE RECORDS data and clear DTCs. Using scan tool, perform Service Bay Test. If scan tool indicates that service bay test passed, go to next step. If service bay test does not pass, go to step 3 .
6. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

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

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for DTCs. If DTC P0443, P0449, P0452 or P0453 is also set, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If DTC P0443, P0449, P0452 or P0453 is not set, go to next step.
3. Using scan tool, monitor FTP sensor. If fuel tank pressure is -0.5 to 0.5 in. H2O, go to step 5 . If fuel tank pressure is not -0.5 to 0.5 in. H2O, go to next step.
4. Turn ignition off. Raise and support vehicle. Disconnect fuel tank wiring harness at body pass-through connector. Turn ignition on, with engine off. Using scan tool, observe FTP sensor voltage. If fuel tank pressure is -0.5 to 0.5 in. H2O, go to step 6 . If fuel tank pressure is not -0.5 to 0.5 in. H2O, go to «DTC P0453»(ref-117480-S35556477642001082000000) .
5. Disconnect purge pipe from EVAP canister purge solenoid. EVAP canister is located forward of fuel tank. Install vacuum gauge to EVAP purge port. Disconnect EVAP canister purge solenoid harness connector. Start and operate engine at idle, then increase engine speed to 1200-1500 RPM. Observe vacuum gauge. If vacuum reading increases, go to step 8 . If vacuum reading does not increase, see «DIAGNOSTIC AIDS»(ref-117480-S11479793622001082000000) .
6. Drop fuel tank from vehicle. Disconnect FTP sensor harness connector. Check fuel tank wiring harness for damage, poor connections, or broken wires inside insulation. Repair as necessary. After repairs, go to step 9 . If no problem is found, go to next step.
7. Replace FTP sensor. After replacing sensor, go to step 9 .
8. Replace EVAP canister purge solenoid. After replacing solenoid, go to next step.
9. Using scan tool, review and record FREEZE FRAME/FAILURE RECORDS data and clear DTCs. Using scan tool, perform Service Bay Test. If scan tool indicates that service bay test passed, go to next step. If service bay test does not pass, go to step 3 .
10. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displays any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

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

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition off. Check A/C compressor for free rotation operation. Start engine. Place HVAC control module in OFF position. If A/C compressor is still engaged, diagnose A/C compressor clutch for not disengaging. See appropriate A/C-HEATER SYSTEM article in AIR CONDITIONING & HEATING. If A/C compressor clutch is disengaged, go to next step.
3. Turn ignition on, with engine off. Using scan tool, command the A/C clutch relay on and off. If A/C clutch relay turns on and off with each command, problem is intermittent. If A/C clutch relay does not turn on and off, go to next step.
4. Turn ignition off. Disconnect A/C clutch relay (located in underhood fuse/relay block). Turn ignition on, with engine off. Using a test light connected to ground, probe A/C clutch relay terminal No. 1239 (power circuit). If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
5. Connect test light between A/C clutch relay terminals No. 459 and 1239. Using scan tool, command A/C clutch relay 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, 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. Check for short to voltage in Dark Green/White wire between PCM harness connector C2 terminal No. 39 and underhood fuse/relay block terminal F7. see scheme 4 Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 10.
8. Check for short to ground in Dark Green/White wire between PCM harness connector C2 terminal No. 39 and underhood fuse/relay block terminal F7. see scheme 4 Repair as necessary. After repairs, go to step 14. If circuit is okay, go to step 10.
9. Check for poor connections at A/C clutch relay. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 12.
10. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14. If connections are okay, go to step 13.
11. Repair ignition 1 voltage circuit of A/C clutch relay at fuse/relay block. After repairs, go to step 14.
12. Replace A/C clutch relay. After replacing relay, go to step 14.
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
14. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S25933635802001091700000). If DTC resets, go to step 3. If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Turn ignition off. Check EBCM and PCM ground circuits. See WIRING DIAGRAMS article. Ensure each ground is clean and tightened properly. Repair as necessary. After repairs, go to step 13 . If no problem is found, go to next step.
3. Turn ignition on, with engine off. Using scan tool, observe the TORQUE REQUEST SIGNAL parameter in PCM data list. If scan tool displays a value of less than 100 percent, problem is intermittent. If scan tool does not display a value of less than 100 percent, go to next step.
4. Turn ignition off. Disconnect EBCM harness connector. EBCM is located under left side of dash, near steering column. Install 100-Pin Breakout Box (J-39700) using a Breakout Box Adapter (J-39700-99) between EBCM harness connector and EBCM. Using a DVOM, check the DC duty cycle between the requested torque signal circuit (EBCM connector terminal C9) and a good ground. If duty cycle is 5-95 percent, go to next step. If duty cycle is not 5-95 percent, go to step 6 .
5. Using DVOM in DC Hertz function, check frequency between the requested torque signal circuit (EBCM connector terminal C9) and a good ground. If frequency is 121-134 Hz, go to step 8 . If frequency is not 121-134 Hz, go to next step.
6. Turn ignition off. Disconnect cable adapter from EBCM harness connector. Turn ignition on, with engine off. Check voltage between ground and EBCM harness connector terminal C9 (Orange/Black wire). If voltage reading is 4-6 volts, go to step 10 . If voltage reading is not 4-6 volts, go to next step.
7. Turn ignition off. Disconnect PCM harness connector. Check Orange/Black wire between EBCM harness connector terminal C9 and PCM harness connector C1 terminal No. 71 for short to voltage or short to ground. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 10 .
8. Turn ignition off. Disconnect PCM harness connector. Check Orange/Black wire between EBCM harness connector terminal C9 and PCM harness connector C1 terminal No. 71 for open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
9. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 11 .
10. Turn ignition off. Check for poor connections at EBCM harness connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to step 12 .
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
12. Replace EBCM. After replacing EBCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S12992568682001091700000) . If DTC resets, go to step 2 . If no DTCs are displayed, system is okay.

Check delivered torque circuit for open, short to ground or voltage terminal corrosion, or poor connection. Check for a communication frequency problem or a communication duty cycle problem. Check EBCM not receiving information from PCM. Check for loose or corroded EBCM or PCM ground.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Check if DTC P1631 is also set. If DTC P1631 is set, go to «DTC P1631»(ref-117480-S00142123512001082000000) . If DTC P1631 is not set, go to next step.
3. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
4. Using scan tool, review and record FAIL RECORDS data. Clear DTCs. Attempt to start engine. If engine starts and continues to run, system is okay. If engine does not start, go to step 2 .

Disconnect and inspect PCM connector. Check for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Perform theft deterrent diagnostic system check. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. After performing theft deterrent diagnostic system check, program theft deterrent system. See «PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS»(ref-117480-S35076856702001082000000) under PROGRAMMING.

A replacement PCM is in a functional state to learn the password from the theft deterrent control module. If theft deterrent control module is replaced, PCM must be placed in password learning mode to relearn the new password. Once learned, password becomes permanent information that remains with vehicle. The loss of PCM battery or ignition voltage does not affect the programmed password information.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC B2960 set as a current code, diagnose DTC B2960. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If DTC B2960 is not set, go to next step.
3. Program theft deterrent system. See «PROGRAMMING THEFT DETERRENT SYSTEM COMPONENTS»(ref-117480-S35076856702001082000000) under PROGRAMMING. After programming, go to next step.
4. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S19458692142001091700000) . If DTC resets, go to step 2 . If no DTCs are displayed, system is okay.

This DTC indicates that PCM has detected an incorrect password from theft deterrent control module. This condition can occur if an incorrect key is being used when attempting to start vehicle or if theft deterrent control module has been replaced and PCM's password learn function has not been enabled.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe the FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S27531089342001091700000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Visually and physically inspect PCM and engine grounds. See WIRING DIAGRAMS article. Ensure that grounds are clean and secure. If a problem is found, repair as necessary. After repairs, go to step 13. If no problem is found, go to next step.
4. Turn ignition off. Disconnect EGR valve harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between chassis ground and EGR harness connector terminal "D" (Gray wire). see scheme 9 If voltage reading is about 5 volts, go to step 6. If voltage reading is not about 5 volts, go to next step.
5. If voltage reading is greater than 5 volts, go to step 9. If voltage reading is not greater than 5 volts, go to step 7.
6. Reconnect EGR valve harness connector. Disconnect throttle position sensor harness connector. Using DVOM, check voltage between chassis ground and TP sensor harness connector harness connector terminal "A" (Gray wire). If voltage reading is about 5 volts, problem is intermittent. If voltage reading is not about 5 volts, go to step 10.
7. Monitor DVOM while disconnecting all other devices (A/C Pressure, ECT, EGR, FTP, IAT and MAP sensors) connected to PCM 5-volt reference circuit one at a time. If voltage changes when one of the components is disconnected, replace affected component. After replacing affected component, 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 harness connector. Check the 5-volt reference circuit for a short to ground or any sensor low reference circuit. Repair as necessary. After repairs, go to step 13. If no problem is found, go to step 12.
9. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Check for short to voltage or short to 5-volt reference circuit in MAP and FTP sensor signal circuits. Repair as necessary. After repairs, go to step 13. If circuits are okay, go to step 12.
10. Turn ignition off. Check for short between EGR control high circuit (Red wire) and 5-volt reference circuit (Gray wire). Repair as necessary. After repairs, go to step 13. If circuits are okay, go to next step.
11. Replace EGR valve. After replacing EGR valve, go to step 13.
12. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
13. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S27531089342001091700000). If DTC runs and passes, go to next step. If DTC resets, go to step 2.
14. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S03744769852001111200000) . If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Visually and physically inspect PCM and engine grounds. See WIRING DIAGRAMS article. Ensure that grounds are clean and secure. Repair as necessary. After repairs, go to step 12 . If no problem is found, go to next step.
4. Turn ignition off. Disconnect A/C pressure sensor harness connector. Connect a DVOM between a known-good ground and A/C pressure sensor harness connector terminal "B" (Gray wire). Turn ignition on, with engine off. If voltage reading is about 5 volts, go to step 10 . If voltage reading is not about 5 volts, go to next step.
5. If voltage reading is greater than 5 volts, go to next step. If voltage reading is not greater than 5 volts, go to step 7 .
6. Turn ignition off. Disconnect PCM harness connector. Check for short to voltage on Gray wire between A/C pressure sensor and PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
7. Turn ignition off. Using DVOM, check continuity between A/C pressure sensor harness connector terminals "A" (Black wire) and "B" (Gray wire). If resistance is infinite, go to next step. If resistance is not infinite, go to step 9 .
8. Leave ignition off. Using DVOM, check continuity between a known-good ground and A/C pressure sensor harness connector "B" (Gray wire). If resistance is infinite, go to step 11 . If resistance is not infinite, go to next step.
9. Repair circuit for short to chassis ground or short to Black wire in A/C pressure sensor circuit. After repairs, go to step 12 .
10. Replace A/C pressure sensor. After replacing sensor, go to step 12 .
11. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repair is completed, go to next step.
12. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S03744769852001111200000) . If DTC runs and passes, go to next step. If DTC resets, go to step 2 .
13. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC or as close to FREEZE FRAME/FAILURE RECORDS data observed. See «CODE ENABLE CRITERIA»(ref-117480-S28837611262001100600000). If DTC fails this ignition, go to next step. If DTC does not fail this ignition, problem is intermittent.
3. Visually and physically inspect PCM and engine grounds. See WIRING DIAGRAMS article. Ensure that grounds are clean and secure. Repair as necessary. After repairs, go to step 17. If no problem is found, go to next step.
4. Turn ignition off. Disconnect A/C pressure sensor harness connector. Connect a DVOM between a known-good ground and A/C pressure sensor harness connector terminal "B" (Gray wire). Turn ignition on, with engine off. If voltage reading is about 5 volts, go to next step. If voltage reading is not about 5 volts, go to step 6.
5. Turn ignition off. Reconnect A/C pressure sensor harness connector. Disconnect Fuel Tank Pressure (FTP) sensor harness connector (located near fuel tank). Connect DVOM between a known-good ground and FTP sensor harness connector terminal "C" (Gray wire). Turn ignition on, with engine off. If voltage reading is about 5 volts, problem is intermittent. If voltage reading is not about 5 volts, go to step 13.
6. If voltage reading is greater than 5 volts, go to next step. If voltage reading is not greater than 5 volts, go to step 8.
7. Turn ignition off. Leave DVOM connected. Disconnect PCM harness connector. Turn ignition on, with engine off. If voltage reading is zero volts, go to step 15. If voltage reading is not zero volts, go to step 12.
8. Turn ignition off. Leave DVOM connected. Disconnect FTP sensor harness connector. Turn ignition on, with engine off. If voltage reading is about 5 volts, go to step 14. If voltage reading is not about 5 volts, go to next step.
9. Turn ignition off. Using DVOM, check continuity of Gray wire between A/C pressure sensor harness connector terminal "B" and PCM harness connector C2, No. 33. Check continuity of Black between A/C pressure sensor harness connector terminal "A" and PCM harness connector C1 terminal No. 80. Check continuity of Gray wire between FTP sensor harness connector terminal "C" and PCM harness connector C2 terminal No. 34. Check continuity of Black wire between FTP sensor harness connector terminal "A" and PCM harness connector C2 terminal No. 35. see scheme 4 If continuity exists, go to step 11. If continuity does not exist, go to next step.
10. Using DVOM, check Gray wire for continuity to a known-good ground and PCM harness connector C2 terminal No. 34. If continuity exists, go to next step. If continuity does not exist, go to step 15.
11. Repair Gray wire for short to chassis ground or short to Black wire at PCM harness connector C1 terminal No. 35 or 80. After repairs, go to step 17.
12. Locate and repair short to voltage in Gray wire. After repairs, go to step 17.
13. Replace A/C pressure sensor. After replacing sensor, go to step 17.
14. Replace FTP sensor. After replacing sensor, go to step 17.
15. Check Gray wire for open, short to chassis ground, or for a poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 17. If circuit is okay, so to next step.
16. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After repair is completed, go to next step.
17. Turn ignition on, with engine off. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running this DTC. If DTC runs and passes, go to next step. See «CODE ENABLE CRITERIA»(ref-117480-S28837611262001100600000). If DTC resets, go to step 2.
18. Using a scan tool, observe stored information and CAPTURE INFO. If scan tool displayed any undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000). If no DTCs are displayed, system is okay.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0560 is set, go to «DTC P0560»(ref-117480-S32588340832001082000000) . If DTC P0560 is not set, go to next step.
3. Using scan tool, select OUTPUT DRIVER DATA LIST. Observe parameters on scan tool. If parameter indicates a fault is present, go to next step. If parameter does not indicate that a fault is present, go to step 5 .
4. Turn ignition off. Check for short to voltage on control circuit of the component that indicated a fault. Repair as necessary. After repairs, go to step 6 . If no problem is found, go to next step.
5. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
6. Turn ignition on, with engine off. Using scan tool, clear DTCs. Warm engine to normal operating temperature. Allow engine to idle. Using scan tool, select DTC and SPECIFIC DTC function. Enter DTC which was set. Operate vehicle within conditions for setting the DTC, until scan tool indicates that diagnostic ran. If scan tool indicates that diagnostic passed, go to next step. If DTC resets, go to step 2 .
7. If scan tool displays any additional undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

An overcharging condition may set this DTC. Check any circuit that is suspected of causing the intermittent complaint. Repair as necessary.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0560 is set, go to «DTC P0560»(ref-117480-S32588340832001082000000) . If DTC P0560 is not set, go to next step.
3. Using scan tool, select OUTPUT DRIVER DATA LIST. Observe parameters on scan tool. If parameter indicates a fault is present, go to next step. If parameter does not indicate that a fault is present, go to step 5 .
4. Check for short to voltage on control circuit of the component that indicated a fault. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 6 . If no problem is found, go to next step.
5. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
6. Turn ignition on, with engine off. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Allow engine to idle. Using scan tool, select DTC and SPECIFIC DTC function. Enter DTC which was set. Operate vehicle within conditions for setting the DTC, until scan tool indicates that diagnostic ran. If scan tool indicates that diagnostic passed, go to next step. If DTC resets, go to step 2 .
7. If scan tool displays any additional undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

An overcharging condition may set this DTC. Check any circuitry that is suspected of causing the intermittent complaint. Repair as necessary.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0560 is set, go to «DTC P0560»(ref-117480-S32588340832001082000000) . If DTC P0560 is not set, go to next step.
3. Using scan tool, select OUTPUT DRIVER DATA LIST. Observe parameters on scan tool. If parameter indicates a fault is present, go to next step. If parameter does not indicate that a fault is present, go to step 5 .
4. Check for short to voltage on control circuit of the component that indicated a fault. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 6 . If no problem is found, go to next step.
5. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
6. Turn ignition on, with engine off. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Allow engine to idle. Using scan tool, select DTC and SPECIFIC DTC function. Enter DTC which was set. Operate vehicle within conditions for setting the DTC, until scan tool indicates that diagnostic ran. If scan tool indicates that diagnostic passed, go to next step. If DTC resets, go to step 2 .
7. If scan tool displays any additional undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

An overcharging condition may set this DTC. Check any circuitry that is suspected of causing the intermittent complaint. Repair as necessary.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. If DTC P0560 is set, go to «DTC P0560»(ref-117480-S32588340832001082000000) . If DTC P0560 is not set, go to next step.
3. Using scan tool, select OUTPUT DRIVER DATA LIST. Observe parameters on scan tool. If parameter indicates a fault is present, go to next step. If parameter does not indicate that a fault is present, go to step 5 .
4. Turn ignition off. Check for short to voltage on control circuit of the component that indicated a fault. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 6 . If no problem is found, go to next step.
5. Turn ignition off. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM, go to next step.
6. Turn ignition on, with engine off. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Allow engine to idle. Using scan tool, select DTC and SPECIFIC DTC function. Enter DTC which was set. Operate vehicle within conditions for setting the DTC, until scan tool indicates that diagnostic ran. If scan tool indicates that diagnostic passed, go to next step. If DTC resets, go to step 2 .
7. If scan tool displays any additional undiagnosed DTCs, diagnose affected DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-117480-S38151331832001082000000) . If no DTCs are displayed, system is okay.

An overcharging condition may set this DTC. Check any circuitry that is suspected of causing the intermittent complaint. Repair as necessary.

1. Perform powertrain diagnostic system check. See «POWERTRAIN DIAGNOSTIC SYSTEM CHECK»(ref-117480-S09475862442001082000000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check, go to next step.
2. Check EBCM ground and PCM ground, making sure each ground is clean and torqued properly. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 11 . If no problem is found, go to next step.
3. Turn ignition on, with engine off. Using scan tool, observe PCM to EBTCM delivered parameter in the TCS DATA LIST. If scan tool displays 90 percent, go to next step. If scan tool does not display 90 percent, problem is intermittent.
4. Turn ignition off. Disconnect EBCM harness connector. Install 100-Pin Breakout Box (J-39700) and Breakout Box Adapter (J-39700-99) between EBCM harness connector and EBCM connector. Disconnect PCM harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between a known-good ground and delivered torque signal circuit (EBCM connector terminal C9) on breakout box adapter. If voltage reading is about battery voltage, go to next step. If voltage reading is not about battery voltage, go to step 6 .
5. Turn ignition off. Disconnect breakout box adapter from EBCM connector. Turn ignition on, with engine off. Using DVOM, check for short to voltage in Tan/Black wire between PCM harness connector C2 terminal No. 9 and EBTCM harness connector terminal C1. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to step 7 .
6. Turn ignition off. Disconnect breakout box adapter from EBCM connector. Check for open, high resistance, or short to ground in Tan/Black wire between PCM harness connector C2 terminal No. 9 and EBTCM harness connector terminal C1. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to step 8 .
7. Inspect for poor connections PCM harness connector. Repair as necessary. After repairs, go to step 11 . If connections are okay, go to step 9 .
8. Check for poor connections the EBCM harness connector. Repair as necessary. After repairs, go to step 11 . If connections are okay, go to step 10 .
9. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE»(ref-117480-S27791892072001082000000) under PROGRAMMING. After replacing PCM , go to next step.
10. Replace EBCM. After replacing EBCM, go to next step.
11. Turn ignition on, with engine off. Using scan tool, clear DTCs. Operate vehicle within the conditions for running this DTC. See «CODE ENABLE CRITERIA»(ref-117480-S08930497822001091700000) . If DTC resets, go to step 2 . If no DTCs are displayed, system is okay.

Check for poor terminal connection. Check harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to check proper tension. Check wiring harness for damage. If harness inspection does not reveal a problem, observe display on scan tool while moving connectors and wiring harnesses related to sensor. A change in scan tool display may indicate location of fault. Check PCM and engine grounds for clean and secure connections.