Engine Controls Self-Diagnostics - 2.2L: Diagnosis Pontiac Sunfire I

ON-BOARD DIAGNOSTICS

Note. For more information on PCM operation, see THEORY & OPERATION - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.

The PCM constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle performance and emissions. The PCM also performs diagnostic tests on various parts of the system. The PCM can recognize operational problems and alert the driver via the Malfunction Indicator Light (MIL). When the PCM detects a malfunction, the PCM stores a Diagnostic Trouble Code (DTC). The problem area is identified by the particular DTC that is set. The PCM supplies a buffered voltage to various sensors and switches. The input and output devices in the PCM include analog-to-digital converters, signal buffers, counters, and output drivers. The output drivers are electronic switches that complete a ground or voltage circuit when turned on. Most PCM controlled components are operated via output drivers. The PCM monitors these driver circuits for proper operation and, in most cases, can set a DTC corresponding to the controlled device if a problem is detected.

PCM is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, PCM will store a DTC and, if DTC is emissions related, the MIL is illuminated. The following are some of the functions that the PCM controls

1. The engine fueling.
2. The Ignition Control Module (ICM).
3. The Knock Sensor (KS) system.
4. The Evaporative Emissions (EVAP) system.
5. The Secondary Air Injection (AIR) system (if equipped).
6. The Exhaust Gas Recirculation (EGR) system.
7. The automatic transmission functions.
8. The generator.
9. The A/C clutch control.
10. The cooling fan control.

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 PIDs 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.

DTC Status

When the scan tool displays a DTC, the status of the DTC is also displayed. The following DTC statuses are indicated only when they apply to the DTC that is set.

DIAGNOSTIC STARTING POINT - ENGINE CONTROLS

Begin the system diagnosis with Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS . The Diagnostic System Check - Engine Controls will provide the following information

1. The identification of control modules which command the system.
2. The ability of control modules to communicate through serial data circuit.
3. The identification of any stored Diagnostic Trouble Codes (DTC) and the code's statuses.

The use of the Diagnostic System Check - Engine Controls will identify the correct procedure for diagnosing the system and where the procedure is located.

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 DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS . DLC is located below left side of dash.

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.

Diagnostic Procedures

Note. DO NOT perform this test if no driveability condition exists. Search for applicable bulletins before proceeding with the diagnosis. DO NOT turn OFF ignition when performing this diagnostic test procedure. DO NOT clear the DTCs unless the diagnostic instructs you to do so. If there is a condition with the starter system, diagnose starter system. 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.

1. Install scan tool. Does scan tool power up? If yes, go to next step. If no, perform SCAN TOOL DOES NOT POWER UP in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
2. Turn ignition switch to RUN position, engine off. Using scan tool, attempt to establish communication with the Body Control Module (BCM), Electronic Brake Control Module (EBCM), Instrument Panel Cluster (IPC), Powertrain Control Module (PCM) and Sensing and Diagnostic Module (SDM). Does scan tool communicate with all the control modules? If yes, go to next step. If no, perform SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. Attempt to start engine. Does engine start and idle? If yes, go to next step. If no, go to «NO-START DIAGNOSIS»(ref-153407-S39462087592003040400000) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
4. Using scan tool, select the DTC display function for the BCM, EBCM, BCM, PCM and SDM. Does scan tool display any DTCs? If yes, go to next step. If no, go to step 9 .
5. Using scan tool, select CAPTURED INFO to store the powertrain DTC information. When complete, go to next step.
6. Does scan tool display DTCs which begin with a "U"? If yes, go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT. If no, go to next step.
7. Were any of PCM DTCs P0601, P0602 or P1621 set? If yes, go to «DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683 OR P2610: ECU MALFUNCTION»(ref-153397-S00260447672003040400000) under DIAGNOSTIC TESTS. If no, go to next step.
8. Does scan tool display DTC P0562, P0563, P0621 or P0622? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
9. Is customer's concern with the automatic transmission? If yes, see appropriate DIAGNOSIS article in AUTOMATIC TRANSMISSIONS. If no, go to next step.
10. Is customer's concern with the Inspection/Maintenance (I/M) testing? If yes, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) under DRIVE CYCLES. If no, go to next step.
11. Check for the following symptoms: Hard start. Surges/chuggles. Lack of power, sluggishness, or sponginess. Detonation/spark knock. Hesitation, sag, stumble. Cuts out/misses. Poor fuel economy. Rough, unstable, or incorrect idle and stalling. Dieseling/run-on. Backfire. MIL inoperative. For repair, see «MIL INOPERATIVE»(ref-153397-S36308401142003040400000) under SYSTEM TESTS. MIL always on. For repair, see «MIL ALWAYS ON»(ref-153397-S32496662112003040400000) under SYSTEM TESTS. Repair as necessary. If no problem is found, problem is intermittent. See «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

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 non-existent 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 the scan tool DTC mode to display enhanced information available. However, to fully utilize information and procedures requires the use of a Tech 2 scan tool. See scan tool operator's manual for additional information.

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

1. Fail This Ign. (Fail This Ignition) - Indicates that this DTC failed during the present ignition cycle.
2. Last Test Fail - Indicates that this DTC failed the last time the test ran. The last test may have run during a previous ignition cycle if an "A" or "B" type DTC is displayed. For type "C" DTCs, the last failure must have occurred during the current ignition cycle to appear as last test fail.
3. MIL Request - Indicates that this DTC is currently requesting the MIL. This selection will report type "B" DTCs only when they have requested the MIL (failed twice).
4. Test Fail SCC (Test Failed Since Code Clear) - Indicates that this DTC that has reported a failure since the last time DTCs were cleared.
5. History - Indicates that the DTC is stored in the PCM History memory. Type "B" DTCs will not appear in History until they have requested the MIL (failed twice). History will be displayed for all type "A" DTCs and type "B" DTCs (which have requested the MIL) that have failed within the last 40 warm-up cycles. Type "C" DTCs that have failed within the last 40 warm-up cycles will also appear in History.
6. Not Run SCC (Not Run Since Code Clear) - DTCs will be listed in this category if the diagnostic has not run since DTCs were last cleared. This status is not included with the DTC display since the DTC can not be set if the diagnostic has not run. This information is displayed when DTC Info is requested using the scan tool.

Note. Many DTC related repairs will instruct the technician to clear the DTC information. This procedure will reset ALL of the I/M system Status indicators to NO, and require performing the I/M Complete System Set Procedure.

1. Perform powertrain diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. Repair any DTCs or driveability concerns that would prevent the I/M system Status tests from completing. Did you find and repair a DTC or driveability concern? If yes, go to step 3 . If no, go to next step.
2. Review any service bulletins for software updates that may prevent I/M readiness. Perform any reprogramming or repairs indicated by the service bulletins. Was a repair service required? If yes, go to «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-153397-S27800244202003040400000) . If no, go next step.
3. Using scan tool, observe the I/M system Status display. Is more than one test indicating a NO status? If yes, go to «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-153397-S27800244202003040400000) . If no, go to appropriate INSPECTION/MAINTENANCE SYSTEM SET procedure for the indicated system.

Diagnostic Aids

The I/M system Status display provides an indication of when the Powertrain Control Module (PCM) has completed the required tests. This does not necessarily mean that the test has passed, only that a decision was made. If the diagnostic fails, a DTC will indicate the 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. For example, a DTC for the control circuit of the relay controlling an AIR pump may not be listed in the I/M system DTC table because it is a continuous test. If this DTC is set, the Active Tests for the AIR system may not run.

The I/M system status information may be useful for a technician to determine if diagnostics have run when verifying repairs.

Conditions For Running Test (Cold Start)

Ensure vehicle meets the following conditions before performing procedure

1. Barometric pressure is greater than 72 kPa.
2. The ECT sensor parameter is less than 84°F (29°C).
3. The IAT sensor parameter is less than 84°F (29°C).
4. The difference between IAT and ECT is 13°F (7°C) or less.
5. Battery voltage is 9-16 volts.
6. Fuel level is 1/4-3/4.

Test will initiate only after a cold start. A cold start is considered when engine coolant temperature is less than 35°F (2°C).

1. Did you perform the Inspection/Maintenance (I/M) system check? If yes, go to next step. If no, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) .
2. Preprogram the scan tool with the vehicle information before the ignition switch is turned to RUN position. Ensure the vehicle is within the Conditions for Running Test (Cold Start). See «CONDITIONS FOR RUNNING TEST (COLD START)»(ref-153397-S22770259672003040400000) . Turn OFF all of the accessories, e.g., A/C, blower fan, etc. Set vehicle parking brake. Verify the transmission is in Park (A/T) or Neutral (M/T). Start the engine and allow engine to idle for 2 minutes. When complete, go to next step.
3. In order for the next group of tests to run, the vehicle must operate in the following conditions: Accelerate at part throttle to 55 MPH. Maintain this speed without changing throttle position for 8-10 minutes until engine reaches operating temperature. Continue operating under these conditions for additional 6 minutes. When complete, go to next step.
4. In order for this test to run, the vehicle must operate in the following conditions: The vehicle speed is reduced to 45 MPH with this speed maintained for one additional minute. Four decelerations of 25 seconds each from 45 MPH while the following criteria is maintained: The throttle is closed, no brake application on either manual or automatic transmissions, no clutch actuation (M/T), no manual downshifts, and 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. When complete, go to next step.
5. In order for the next group of tests to run, the vehicle must operate in the following conditions: Accelerate at part throttle to 45-55 MPH and maintain this speed for 2 minutes, then decelerate to zero MPH. With engine idling for 2 minutes, the following criteria should be maintained: Service brake depressed, transmission in Drive (A/T) or Neutral (M/T) with clutch pedal depressed. When complete, go to next step.
6. Using a scan tool, observe the I/M system Status display. Did all of the I/M system Status indicators update to YES? If yes, go to next step. If no, go to the I/M system Set Procedure for the indicated systems.
7. Using scan tool, observe emission related DTC portion of I/M system status display. Does the scan tool indicate any emission related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

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

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

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

Conditions For Running Test

1. BARO is more than 72 kPa.
2. ECT sensor parameter is 167-257°F (75-125°C).
3. IAT sensor parameter is -4 to 176°F (-20 to 80°C).
4. Engine is in closed loop.
5. Engine has run 6-8 minutes off idle to initiate test
6. Battery voltage is 9-16 volts.

Diagnostic Procedure

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) . After performing I/M system check, go to next step.
2. Ensure that the vehicle is within the Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S01069292582003040400000) . Turn all of the accessories OFF, such as the A/C, blower fan, etc. Start the engine and allow to idle. In order for this test to run, the vehicle must operate 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 brake applied, A/T in Drive or M/T in Neutral with clutch depressed. Using scan tool, monitor I/M SYSTEM STATUS. Did the Catalyst System Status update to YES? If yes, go to step 5 . If no, go to next step.
3. Using scan tool, observe DTC information. Does scan tool indicate any failed DTCs? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
4. Refer to Inspection/Maintenance (I/M) System DTCs to determine which DTCs are required to run to complete this test. See «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-153397-S13999204262003040400000) . Use scan tool to observe the NOT RAN SINCE CODE CLEARED display. Determine which of DTCs required for a YES status has not run. Enter DTC number in the Specific DTC menu of scan tool. Operate vehicle within Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S01069292582003040400000) . Repeat the procedure until scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Use a scan tool to observe the I/M System Status display. Did the CATALYST SYSTEM STATUS update to YES? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S38513399282003040400000) .
5. Use a scan tool to observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any emission related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

The Powertrain Control Module (PCM) runs a maximum of 6 tests per trip until the Catalyst System Status updates to YES. If the status does not update, the test outlined in this procedure can be repeated until the I/M System Status updates to YES.

The I/M System Status does not indicate whether the test has passed or failed, only that a decision was made. When all of the diagnostics for a specific system have run and passed, the I/M System Status 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 the Malfunction Indicator Light (MIL) is requested. The I/M System Status also registers the number of Diagnostic Trouble Codes (DTCs).

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

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the 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, maintain necessary enable conditions until the system status updates to YES.

Note. This is for non scan tool Service Bay Test equipped vehicles.

1. BARO sensor parameter is greater than 75 kPa.
2. The ECT sensor parameter is 46-167°F (8-75°C).
3. The IAT sensor parameter is 46-122°F (8-50°C).
4. The fuel level is 1/4-3/4.
5. The battery voltage is 11-16 volts.
6. The engine is in Closed Loop fuel control.
7. The vehicle has been driven for 17 minutes.

1. Did you perform the Inspection/Maintenance (I/M) system check? If yes, go to next step. If no, go to «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) .
2. Using a scan tool, select SPECIAL FUNCTIONS. Determine if the vehicle is equipped with a Service Bay Test for the EVAP system. Is the vehicle equipped with EVAP Service Bay Test? If yes, go to next step. If no, go to step 5 .
3. Ensure that the vehicle is within the Conditions for Running. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S33062742342003040400000) . Turn OFF all of the accessories, such as A/C, blower fan, etc. Following the directions on the scan tool, perform the EVAP Service Bay Test. Did the EVAP system pass the Service Bay Test? If yes, go to step 8 . If no, go to next step.
4. Observe the scan tool Service Bay Test for an indication of why the test did not pass, e.g., failed DTC, test aborted, etc. Refer to the appropriate service information for diagnosis and repair of the condition as necessary. After repairs, «INSPECTION/MAINTENANCE COMPLETE SYSTEM SET PROCEDURE»(ref-153397-S27800244202003040400000) .
5. Ensure vehicle is within the Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S33062742342003040400000) . Turn all of the accessories OFF, e.g., A/C, blower fan, etc. Start the engine and let idle. Accelerate at part throttle to 45 MPH and maintained speed until engine reaches operating temperature. This may be up to 8-10 minutes depending on the start up coolant temperature. Continue the operating conditions for an additional 3 minutes after the engine reaches operating temperature, or until the I/M System Status indicator updates to YES. Decelerate to zero MPH. Operate engine at idle 2 minutes. Did the EVAP System Status update to YES? If yes, go to step 8 . If no, go to next step.
6. Using a scan tool, observe the DTC Information. Does the scan tool indicate any failed DTCs? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
7. Determine which DTCs are required to run in order to complete this test. See «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-153397-S13999204262003040400000) . Using a scan tool, observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the SPECIFIC DTC menu of the scan tool. Operate the vehicle within the Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S33062742342003040400000) . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using a scan tool, observe the I/M System Status display. Did the EVAP System Status update to YES? If yes, go to next step.
8. Using a scan tool, observe the emission related DTC portion of the I/M System Status display. Does the scan tool indicate any emission related DTCs set? If yes, «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

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. The ECT sensor parameter is more than 167°F (75°C).
2. Engine is in closed loop.
3. Engine has been running more than 4 minutes.
4. Battery voltage is 10-16 volts.

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) . After performing I/M system check, go to next step.
2. Ensure the vehicle is within the Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S23527483202003040400000) . Turn all of the accessories OFF, e.g., A/C, blower fan, etc. Start the engine and allow to idle. In order for this test to run, the vehicle must operate in the following conditions: Accelerate at part throttle to 45-55 MPH with this speed maintained for 6 minutes. Decelerate to zero MPH, operate engine at idle for 2 minutes. While the following criteria is maintained: Ensure service brake is depressed Transmission in Drive (A/T) or Neutral (M/T) with clutch pedal depressed. Using scan tool, review the I/M System Status display. Did the HO2S/O2S System Status update to YES? If yes, go to step 5 . If no, go to next step.
3. Using scan tool, observe DTC information. If scan tool indicates any failed DTCs, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Determine which DTCs are required to run in order to complete this test. See «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-153397-S13999204262003040400000) . Using a scan tool, observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter DTC number in the Specific DTC menu of scan tool. Operate vehicle within the Conditions for Running Test. See «CONDITIONS FOR RUNNING TEST»(ref-153397-S23527483202003040400000) . Repeat the procedure until scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using scan tool, observe the I/M System Status display. Did the HO2S/O2S System Status update to YES? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S00585315692003040400000) .
5. Using a scan tool, observe the Emission Related DTC portion of the I/M System Status display. Does the scan tool indicate any emission related DTCs set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

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. The ECT sensor parameter is less than 113°F (45°C).
2. The IAT sensor parameter is less than 113°F (45°C).
3. Difference between ECT and IAT is less than 13°F (7°C).
4. Battery voltage is 11.6-16.0 volts.

1. Perform I/M system check. See «INSPECTION/MAINTENANCE SYSTEM CHECK»(ref-153397-S12744205992003040400000) . After performing I/M system check, go to next step.
2. Pre-program scan tool with vehicle information before ignition switch is turned to RUN position. Ensure vehicle is within enable criteria. Set vehicle parking brake. Verify transmission is in Park for A/T and Neutral for M/T. Turn off all of accessories. Start the engine and allow it to idle for 2 minutes or until I/M SYSTEM STATUS indicator updates to YES. If HO2S HEATER SYSTEM STATUS updates to YES, go to step 5 . If HO2S HEATER SYSTEM STATUS 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-153397-S21975802792003040400000) . If scan tool does not indicate any failed DTCs, go to next step.
4. Determine which DTCs are required to run in order to complete this test. See «INSPECTION/MAINTENANCE SYSTEM DTCS»(ref-153397-S13999204262003040400000) . Using scan tool, observe the NOT RAN SINCE CODE CLEARED display. Determine which of the DTCs required for a YES status has not run. Enter the DTC number in the SPECIFIC DTC menu of the scan tool. Operate vehicle within the Conditions for Running Test. «CONDITIONS FOR RUNNING TEST»(ref-153397-S30519910412003040400000) . Repeat the procedure until the scan tool indicates the diagnostic test has run. Repeat this step for any additional required DTCs that have not run. Using scan tool, observe the I/M System Status display. Did the HO2S Heater System Status update to YES? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S38513399282003040400000) .
5. Using scan tool, check for DTCs. If scan tool indicates any DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no DTCs are set, system is okay at this time.

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.

The I/M System Status will update only when an emission related DTC fails the second time, or when all of the tests pass.

If there is an impending failure, the system may require more time to run the diagnostic than was allotted in the set procedure. If the test does not run after numerous attempts and no DTC is set, review the appropriate scan tool data list and the 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, maintain necessary enable conditions until the system status updates to YES.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Note. Use of Tech 2 or generic OBD-II scan tool is required to retrieve DTCs. Refer to user reference manual supplied using scan tool.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Circuit Description

Battery positive voltage is supplied directly to the Malfunction Indicator Light (MIL). The Powertrain Control Module (PCM) turns the MIL ON by grounding the MIL control circuit. There should be a steady MIL with the ignition switch in RUN position and the engine OFF.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Verify whether the instrument cluster is operational. If the Instrument Panel (IP) is completely inoperative, see DIAGNOSTIC SYSTEM CHECK - INSTRUMENT CLUSTER in appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Command the MIL ON and OFF, using scan tool. Does the MIL turn ON and OFF when commanded using a scan tool? If yes, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article. If no, go to next step.
3. Inspect the fuse that supplies battery positive voltage to the MIL. Is the fuse open? If yes, go to step 10 . If no, go to next step.
4. Turn ignition switch to OFF position. Remove the fuse that supplies voltage to the MIL. Disconnect the Powertrain Control Module (PCM) harness connectors. Turn ignition switch to RUN position, engine OFF. Measure voltage between the MIL control circuit in the PCM harness connector and a good ground. Is the voltage less than 0.3 volt? If yes, go to next step. If no, go to step 11 .
5. Turn ignition switch to OFF position. Install the fuse that supplies voltage to the MIL. Turn ignition switch to RUN position, engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit in the PCM harness connector and a good ground. Is the MIL illuminated? If yes, go to step 9 . If no, go to next step.
6. Turn ignition switch to OFF position. Remove the Instrument Panel Cluster (IPC). Go to appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT. Probe the MIL battery positive voltage circuit of the IPC harness connector using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 12 .
7. Check the MIL control circuit for an open or high resistance. Did you find and correct a condition? If yes, go to step 15 . If no, go to next step.
8. Check for an intermittent and for a poor connection at the IPC. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
9. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
10. Repair the short to ground in the battery positive voltage circuit. After repair, go to step 15 .
11. Repair the short to voltage in the MIL control circuit. After repair, go to step 15 .
12. Repair the open in the MIL battery positive voltage circuit. After repair, go to step 15 .
13. Replace the IPC. Go to appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT. After repair, go to step 15 .
14. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After repair, go to next step.
15. Remove all test equipment. Connect any disconnected components or any disconnected fuses. Turn ignition switch to OFF position for 30 seconds. Start the engine and operate the vehicle performance, and driveability. Observe the MIL, the vehicle performance, and the driveability. Does the vehicle operate correctly, without any MIL illumination and without any stored DTCs? If yes, system is okay at this time. If no, diagnose appropriate DTC. Go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) .

Battery positive voltage is supplied directly to the Malfunction Indicator Light (MIL). The PCM turns the MIL ON by grounding the MIL control circuit.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to OFF position. Disconnect PCM harness connectors. Turn ignition switch to RUN position, engine off. Observe the MIL. Is the MIL illuminated? If yes, go to next step. If no, go to step 5 .
3. Check the MIL control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 6 . If no, go to next step.
4. Replace IPC. Go to appropriate INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT. After replacing IPC, go to step 6 .
5. Replace PCM. See appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After repair, go to next step.
6. Turn ignition switch to OFF position for 30 seconds. Start the engine. Does the vehicle operate correctly without any unwanted MIL illumination, and without any stored DTCs? If yes, system is okay at this time. If no, go to «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) .

If the problem is intermittent, refer to go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

DIAGNOSTIC TESTS

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

Conditions For Running DTC

1. DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0171, P0172, P0201-P0204, P0300, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507, P0601, P0602, P1441, P1621 or P1860 are not set.
2. Engine run time is more than 40 seconds.
3. Engine speed is 600-6375 RPM.
4. Torque Converter Clutch (TCC) is stable to within 1.2 percent.
5. Engine speed is stable within 50 RPM.
6. IAC valve is stable within 5 counts.
7. Conditions are present for 1.5 seconds.

Conditions For Setting DTC

The MAP sensor or the TP sensor is out of an expected range defined by the engine calibration for 14 seconds.

Actions Taken When DTC Sets

1. The Powertrain Control Module (PCM) illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions For Clearing MIL/DTC

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Connect scan tool. Turn ignition switch to RUN position, engine off. Observe the TP sensor voltage on the scan tool. Does the scan tool display a TP voltage less than 0.9 volt when throttle is fully closed? If yes, go to next step. If no, go to step 4 .
3. Select TP angle parameter on the scan tool. Monitor scan tool while slowly depressing accelerator pedal to the floor, then slowly release pedal. Repeat the procedure several times. Does the TP angle value increase steadily when accelerator pedal is depressed to more than 98 percent value and decrease steadily, returning to less than one percent value when pedal is released? If yes, go to step 5 . If no, go to step 22 .
4. Check throttle body for binding linkage or damaged linkage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 22 .
5. Do you have access to another vehicle in which the MAP sensor pressure can be observed using a scan tool? If yes, go to next step. If no, go to step 7 .
6. Turn ignition switch to RUN position, engine OFF. Observe the MAP sensor pressure using a scan tool. Observe the MAP sensor pressure in the known good vehicle using a scan tool. Compare the values. Is the difference between the values less than 3 kPa? If yes, go to step 8 . If no, go to step 12 .
7. Turn ignition switch to RUN position, engine OFF. Observe the MAP sensor pressure using a scan tool. See «ALTITUDE VS. BAROMETRIC PRESSURE»(ref-153397-S08332913562003041800000) table. The MAP sensor pressure should be within the range specified for your altitude. Does the MAP sensor indicate the correct barometric pressure? If yes, go to next step. If no, go to step 12 .
8. Start the engine while watching the MAP sensor value using the scan tool. Does the MAP sensor value change while starting the engine? If yes, go to next step. If no, go to step 11 .
9. With the engine running, snap the throttle while watching the MAP sensor display on the scan tool. Does the MAP sensor value change rapidly when the throttle position changes? If yes, go to next step. If no, go to step 11 .
10. Allow the engine to reach operating temperature. Ensure that the transaxle is in Park (A/T) or Neutral (M/T). Turn all accessories OFF. Allow engine to idle. Observe the MAP sensor pressure using a scan tool. Is the MAP sensor pressure 19-39 kPa? If yes, go to «DIAGNOSTIC AIDS»(ref-153397-S08795623272003040400000) . If no, go to next step.
11. Turn ignition switch to OFF position. Remove the MAP sensor from the vacuum source. Inspect the port for vacuum restrictions and vacuum leaks. Did you find and correct the condition? If yes, go to step 41 . If no, go to next step.
12. Turn ignition switch to OFF position. Disconnect the MAP sensor harness connector. Turn ignition switch to RUN position. Observe the MAP sensor voltage on the scan tool. Does the scan tool indicate that the voltage is near zero volt? If yes, go to next step. If no, go to step 16 .
13. Measure the voltage between the 5-volt reference circuit of the MAP sensor and a good ground using a DMM. Is the voltage more than 5.2 volts? If yes, go to step 18 . If no, go to next step.
14. Connect a test light to a good ground. Probe the 5-volt reference circuit of the MAP sensor using the test light. Does the test light illuminate? If yes, go to next step. If no, go to step 19 .
15. Connect a 3-amp fused jumper to the MAP sensor 5-volt reference circuit. Connect the other end of the 3-amp fused jumper to the MAP sensor signal circuit. Does the scan tool indicate that the MAP sensor voltage is near 5 volts? If yes, go to step 17 . If no, go to step 20 .
16. Check the MAP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
17. Remove the jumper wire. Connect a jumper wire between each of the terminals in the MAP sensor harness connector and the corresponding terminal at the MAP sensor. Turn ignition switch to RUN position, engine OFF. Measure the voltage from the low reference circuit of the MAP sensor, at the jumper wire terminal, to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step 21 . If no, go to step 35 .
18. Check all of the 5-volt reference circuits for a short to voltage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
19. Check the 5-volt reference circuit of the MAP sensor for an open, high resistance or a short to ground. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
20. Check the MAP sensor signal circuit for an open, a short to ground or high resistance. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 37 .
21. Check the MAP sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 37 .
22. Turn ignition switch to OFF position. Disconnect the TP sensor harness connector. Turn ignition switch to RUN position, engine off. Observe the TP sensor voltage on the scan tool. Does the scan tool indicate that the TP sensor voltage is near zero volt? If yes, go to next step. If no, go to step 26 .
23. Connect a test light to a good ground. Probe the 5-volt reference circuit of the TP sensor. Does the test light illuminate? If yes, go to next step. If no, go to step 28 .
24. Measure the voltage between the TP sensor 5-volt reference circuit and a good ground. Does the voltage measure more than 5.2 volts? If yes, go to step 31 . If no, go to next step.
25. Connect a 3-amp fused jumper between the TP sensor 5-volt reference circuit and the TP sensor signal circuit. Does the scan tool indicate the TP sensor voltage is near 5 volts? If yes, go to step 27 . If no, go to step 32 .
26. Check the TP sensor signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
27. Remove the jumper wire. Connect a jumper wire between each of the terminals in the TP sensor harness connector and the corresponding terminal at the TP sensor. Turn ignition switch to RUN position, engine OFF. Measure the voltage from the low reference circuit of the TP sensor, at the jumper wire terminal, to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step 33 . If no, go to step 36 .
28. Check the 5-volt reference circuit of the TP sensor for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step 41 . If no, go to next step.
29. Check all of the branches of the 5-volt reference circuits that are shared with the TP sensor for a short to ground. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 30 .
30. Measure the voltage from the 5-volt reference circuit of the TP sensor to the low reference circuit of the TP sensor. Disconnect all of the other sensors that share the 5-volt reference circuit with the TP sensor, one at a time. A change in voltage indicates the faulty component. Replace that component as necessary. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 34 .
31. Check the 5-volt reference circuit of the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 37 .
32. Check the TP sensor signal circuit for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 37 .
33. The TP sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 37 .
34. Check all of the 5-volt reference circuits that are shared with the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
35. Inspect for poor connections at the MAP sensor. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 38 .
36. Inspect for poor connections at the TP sensor harness connector. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 39 .
37. Inspect for poor connections at the PCM. Did you find and correct the condition? If yes, go to step 41 . If no, go to step 40 .
38. Replace the MAP sensor. After repair, go to step 41 .
39. Replace the TP sensor. After repair, go to step 41 .
40. Replace the PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After repair, go to step 42 .
41. Use the scan tool to perform the Fuel Trim Reset procedure. Did you complete the procedure? If yes, go to next step.
42. Clear the DTCs using scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S38693095202003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
43. Observe the CAPTURE INFO using the scan tool. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

(1) ALTITUDE VS. BAROMETRIC PRESSURE

1. If a DTC P0105 cannot be duplicated, information included in FREEZE FRAME/FAILURE RECORDS data can be useful. Use scan tool DTC information data in order to determine status of DTC.
2. A DTC P0105 may set due to any condition that may cause an unreasonably high or low MAP value including incorrect cam timing, restricted exhaust, worn piston rings or low fuel pressure.
3. A TP sensor that is stuck may attempt to auto zero every time engine runs. If this happens, TP percentage will be zero percent and TP voltage will be high.
4. MAP sensor needs a dedicated vacuum source. Check MAP sensor and MAP sensor vacuum source for a vacuum leak.
5. A short on any branch of the 5-volt reference circuit may cause this DTC to set.
6. Inspect for corroded terminals at the MAP sensor, TP sensor and PCM.

1. DTCs P0122 or P0123 are not set.
2. The ignition switch is in RUN position.
3. The engine speed is less than 1000 RPM, Or
4. The engine speed is less than 1000 RPM or the engine speed is more than 1000 RPM and Throttle Position (TP) sensor parameter is more than 15 percent.

The MAP sensor voltage is less than 0.2 volt for at least 6.25 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

Test Conditions

The number below refers to the step number on the diagnostic procedure.

1. 3 - Operate the vehicle within the same conditions which caused the DTC to fail. If you cannot duplicate the DTC, the information included in the Freeze Frame/Failure Records can aid in locating an intermittent condition.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine off. Using a scan tool, observe MAP sensor voltage. Does the scan tool indicate that the voltage is less than 0.2 volt? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S33776173862003040400000) . Does the DTC fail this ignition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S41654304352003040400000) .
4. Turn ignition switch to OFF position. Disconnect MAP sensor harness connector. Turn ignition switch to RUN position, engine off. Probe the 5-volt reference circuit of the MAP sensor using a test light connected to a good ground. Is the test light OFF? If yes, go to step 6 . If no, go to next step.
5. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the MAP sensor and the signal circuit of the MAP sensor. Does the scan tool indicate that the voltage is about 5 volts? If yes, go to step 8 . If no, go to step 7 .
6. Check the 5-volt reference circuit of the MAP sensor for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Check the signal circuit of the MAP sensor for an open, short to ground or high resistance. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Inspect for faulty connections at the MAP sensor. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Inspect for faulty connections at the PCM. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace MAP sensor. After replacing sensor, go to step 12 .
11. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
12. Using scan tool, perform the FUEL TRIM RESET procedure. When complete, go to next step.
13. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S33776173862003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
14. Using scan tool, observe CAPTURE INFO. If any DTCs are displayed that have not been diagnosed, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

If a components 5-volt reference circuit is shorted to ground or shorted to voltage, the other 5-volt reference circuits may be affected.

If this DTC is determined to be intermittent, refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0122 or P0123 are not set.
2. The Throttle Position (TP) sensor parameter is less than 12 percent.
3. The vehicle speed is less than one MPH.
4. The engine run time is more than 40 seconds.

The MAP sensor voltage is more than 3.8 volts for at least 1.25 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Start the engine. Let engine idle. Does the scan tool indicate that the MAP sensor voltage is greater than 3.8 volts? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S28662435212003040400000) . Does the DTC fail this ignition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S01418782302003040400000) .
4. Turn ignition switch to OFF position. Inspect the MAP sensor vacuum source for leaks, faulty connections or restrictions. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
5. Disconnect MAP sensor harness connector. Turn ignition switch to RUN position, engine off. Does the scan tool indicate that the MAP sensor voltage is less than 0.2 volt? If yes, go to next step. If no, go to step 8 .
6. Measure the voltage from the 5-volt reference circuit to the low reference circuit at the MAP sensor harness connector. Does the voltage measure more than 5.2 volts? If yes, go to step 10 . If no, go to next step.
7. Connect a jumper wire between each of the terminals in the MAP sensor harness connector and the corresponding terminal at the MAP sensor. Measure the voltage from the low reference circuit of the MAP sensor at the jumper wire terminal to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to step 9 . If no, go to step 11 .
8. Check the signal circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Check the low reference circuit of the MAP sensor for an open or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Check the 5-volt reference circuit of the MAP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
11. Inspect for faulty connections at the MAP sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Inspect for faulty connections at the PCM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace MAP sensor. After repair, go to step 15 .
14. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to step 16 .
15. Use the scan tool to perform the FUEL TRIM RESET procedure. When complete, go to next step.
16. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S28662435212003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
17. Observe the CAPTURE INFO using a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. If a component's 5-volt reference circuit is shorted to ground or shorted to voltage, the other 5-volt reference circuits may be affected.
2. Inspect the MAP sensor vacuum source for leaks, restrictions or faulty connections.
3. This DTC may set as the result of a misfire.
4. This DTC may set as the result of a misfire.
5. If this DTC is determined to be intermittent, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0117, P0118, P0125, P0502 or P0503 are not set.
2. The engine run time is more than 5 minutes.
3. The Vehicle Speed Sensor (VSS) indicates that vehicle speed is more than 15 MPH.

The IAT sensor signal voltage indicates that the intake air temperature is more than 262°F (128°C) for 6 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Observe the Intake Air Temperature (IAT) sensor parameter using a scan tool. Is the IAT sensor parameter more than 262°F (128°C)? If yes, go to step 4 . If yes, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition witch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S23164186382003040400000) . Does the DTC reset? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S27463240252003040400000) .
4. Turn ignition switch to OFF position. Disconnect IAT sensor. Turn ignition switch to RUN position, engine off. Observe the IAT sensor temperature using a scan tool. Is the IAT sensor temperature less than -38°F (-39°C). If yes, go to step 6 . If no, go to next step.
5. Check the signal circuit of the IAT sensor for a short to ground or a short to IAT low reference circuit. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
6. Check for an intermittent and for a poor connection at the IAT sensor. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
7. Replace the IAT sensor. After repair, go to step 10 .
8. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
9. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
10. Use the scan tool to clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S23164186382003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
11. Using scan tool, observe the CAPTURE INFO. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

When the vehicle is at ambient temperature the IAT sensor and Engine Coolant Temperature (ECT) sensor temperatures should be relatively close to each other. See TEMPERATURE VS. RESISTANCE table.

If an intermittent condition is suspected, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

TEMPERATURE VS. RESISTANCE

1. DTCs P0117, P0118, P0125, P0502 or P0503 are not set.
2. The engine run time is more than 5 minutes.
3. The Vehicle Speed Sensor (VSS) indicates that vehicle speed is less than 15 MPH.

The IAT sensor signal voltage indicates that the intake air temperature is less than -38°F (-39°C) for 6.25 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Connect scan tool. Turn ignition switch to RUN position, with engine off. Observe the IAT sensor parameter. Is the IAT sensor temperature less than -36°F (-38°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S32760049282003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC reset? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S29957883382003040400000) .
4. Turn ignition switch to OFF position. Disconnect IAT sensor harness connector. Connect a Digital Multimeter (DMM) between the signal circuit of the IAT sensor and a good ground. Turn ignition switch to RUN position. Does the DMM voltage measure more than 5.2 volts? If yes, go to next step. If no, go to step 6 .
5. Check the signal circuit for a short to voltage. Repair as necessary. Did you find and correct the condition? If yes, go to step 15 . If no, go to 12 .
6. Turn ignition switch to OFF position. Disconnect IAT sensor harness connector. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor and the low reference circuit at the IAT sensor harness connector. Turn ignition switch to RUN position, engine off. Observe the IAT sensor temperature using a scan tool. Is the IAT sensor temperature more than 262°F (128°C)? If yes, go to step 10 . If no, go to next step.
7. Turn ignition switch to OFF position. Connect a 3-amp fused jumper wire between the signal circuit of the IAT sensor harness connector and a known-good ground. Turn ignition switch to RUN position, engine off. Observe the IAT sensor temperature using a scan tool. Is the IAT sensor temperature more than 262°F (128°C)? If yes, go to step 9 . If no, go to next step.
8. Check the signal circuit of the IAT sensor for an open circuit or high resistance. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Check the IAT sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Check the IAT signal circuit for a short to any 5-volt reference circuit. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
11. Check for an intermittent and for a poor connection at the IAT sensor. Repair as necessary. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Check for an intermittent and for a poor connection at the PCM. Repair as necessary. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the IAT sensor. After repair, go to step 15 .
14. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
15. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S32760049282003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to 2 .
16. Observe the CAPTURE INFO using a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. When the vehicle is at ambient temperature the IAT sensor and ECT sensor temperatures should be relatively close to each other. See «TEMPERATURE VS. RESISTANCE»(ref-153397-S33004112412003040400000) table.
2. If a short to a separate 5-volt source occurs this DTC may set. If this condition exists, a continuity test to all other PCM 5-volt reference circuits will be necessary.
3. If an intermittent condition is suspected, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The engine has been running more than 2 minutes.

The PCM detects that the ECT sensor parameter is more than 280°F (138°C) for more than 6 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Install scan tool. Turn ignition switch to RUN position, engine off. Observe the ECT sensor parameter. Does the scan tool indicate that the ECT sensor temperature is more than 280°F (138°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S07392787562003040400000) . Does the DTC reset? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S36650319882003040400000) .
4. Disconnect ECT sensor. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the ECT sensor temperature. Does the scan tool indicate that the ECT sensor temperature is less than -36°F (-38°C). If yes, go to step 6 . If no, go to next step.
5. Check the signal circuit of the ECT sensor for a short to ground or a short to any low reference circuit. Did you find and correct the condition? If yes, go to step 10 . If no, go to step 8 .
6. Check for an intermittent and for a poor connection at the ECT sensor. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
7. Replace ECT sensor. After repair, go to step 10 .
8. Check for an intermittent and for a poor connection at the Powertrain Control Module (PCM). Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
9. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
10. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S07392787562003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
11. Observe the CAPTURE INFO using a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. An overheating condition may cause DTC to set.
2. After starting engine, ECT sensor temperature should rise steadily to about 194°F (90°C), then stabilize after thermostat opens.
3. Use the Temperature vs. Resistance Value Table to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. See «TEMPERATURE VS. RESISTANCE»(ref-153397-S33004112412003040400000) table.
4. If this DTC is determined to be intermittent, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The engine has been running more than 60 seconds.

The PCM detects that the ECT sensor parameter less than -38°F (-39°C) for more than 6 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Install scan tool. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the ECT sensor parameter. Does the scan tool indicate that the ECT sensor temperature is less than -38°F (-39°C)? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S38842947372003040400000) . Does the DTC reset? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect ECT sensor harness connector. Measure the voltage from the signal circuit of the ECT sensor to a good ground using a DMM. Is the voltage more than 5.2 volts? If yes, go to next step. If no, go to step 6 .
5. Check the ECT signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
6. Connect a 3-amp fused jumper between the signal circuit of the ECT sensor and the low reference circuit. Observe the ECT sensor parameter using the scan tool. Is the ECT sensor parameter more than 280°F (138°C)? If yes, go to step 10 . If no, go to next step.
7. Connect a 3-amp fused jumper wire between the signal circuit of the ECT sensor and a good ground. Observe the ECT sensor parameter using a scan tool. Is the ECT sensor parameter more than 280°F (138°C)? If yes, go to step 9 . If no, go to next step.
8. Check the signal circuit of the ECT sensor for high resistance or an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
9. Check the ECT sensor low reference circuit for high resistance or an open. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 12 .
10. Check the ECT signal circuit for a short to any 5-volt reference circuit. Did you find and correct the condition? If yes, go to step 15 . If no, go to next step.
11. Check for an intermittent and for a poor connection at the ECT sensor. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 13 .
12. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 15 . If no, go to step 14 .
13. Replace the ECT sensor. After repair, go to step 15 .
14. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
15. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S38842947372003040400000) . You may also operate he vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
16. Using scan tool, observe CAPTURE INFO. Does scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. If a short to a separate 5-volt source occurs this DTC may set. If this condition exists, a continuity test to all other PCM circuits will be necessary to diagnose the specific circuit.
2. After starting the engine, the ECT should rise steadily to about 194°F (90°C) then stabilize after the thermostat opens.
3. Use the Temperature vs. Resistance table in order to test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor could result in poor driveability concerns. See «TEMPERATURE VS. RESISTANCE»(ref-153397-S33004112412003040400000) table.
4. If this DTC is determined to be intermittent, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The engine is running.

1. TP sensor signal voltage is less than 0.1 volt.
2. Condition is present for longer than 2 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Connect scan tool. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the TP voltage parameter. Does the scan tool indicate that the TP sensor voltage is less than 0.1 volt? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S09704617452003040400000) . Does the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect TP sensor harness connector. Connect a fused jumper wire between the TP sensor 5-volt reference circuit and the TP sensor signal circuit at the TP sensor harness connector. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the TP sensor voltage parameter. Does the scan tool indicate TP sensor voltage at 5 volts? If yes, go to step 10 . If no, go to next step.
5. Using a Digital Multimeter (DMM), test the TP sensor 5-volt reference circuit for an open or high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
6. Check all 5-volt reference circuits for a short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
7. Connect a DMM between the TP sensor 5-volt reference circuit and the TP sensor low reference circuit. Observe the voltage while disconnecting all sensors, one at a time, that use a 5-volt reference signal. A change in voltage indicates the faulty component. Replace that component as necessary. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
8. Using a DMM, test the TP sensor signal circuit for an open, high resistance, or short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
9. Inspect for faulty connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
10. Check the TP sensor 5-volt reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
11. Inspect for faulty connections at the TP sensor harness connector. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
12. Replace TP sensor. After repair, go to step 14 .
13. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
14. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S09704617452003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
15. Using a scan tool, observe stored information. Does the scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0107 or P0108 are not set.
2. The engine is running.

1. TP sensor signal voltage is more than 4.8 volts. Or
2. TP sensor signal voltage is more than 3.9 volts when the engine speed is less than 1500 RPM and the MAP is less than 60 kPa.
3. Conditions are present for longer than 14 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the TP sensor voltage parameter with the throttle closed. Does the scan tool indicate that the TP sensor voltage is greater than 4.9 volts? If yes, step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Operate the vehicle within the Conditions for Running the DTC or within the conditions in the Freeze Frame/Failure Records. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S21241144002003040400000) . Does the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect TP sensor harness connector. Turn ignition switch to RUN position, engine off. Using a scan tool, observe the TP sensor voltage parameter. Does the scan tool indicate that the TP voltage is zero volts? If yes, go to next step. If no, go to step 7 .
5. Using a Digital Multimeter (DMM), measure the voltage between the 5-volt reference circuit of the TP sensor to a good ground using a DMM. Does the voltage measure more than 5.2 volts? If yes, go to step 9 . If no, go to next step.
6. Connect a jumper wire between each of the terminals in the TP sensor harness connector and the corresponding terminal at the TP sensor. Measure the voltage from the low reference circuit of the TP sensor at the jumper wire terminal to a good ground using a DMM. Is the voltage more than 0.2 volt? If yes, go to next step. If no, go to step 10 .
7. Check the low reference circuit of the TP sensor for a high resistance or an open. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
8. Check the signal circuit of the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 13 . If no, go to next step.
9. Check all of the 5-volt reference circuits that are shared with the TP sensor for a short to voltage. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
10. Inspect for faulty connections at the harness connector of the TP sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Inspect for faulty connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace TP sensor. After repair, go to step 14 .
13. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
14. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S21241144002003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using scan tool, observe stored information. Does scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301-P0304, P0335, P0336, P0440, P0442, P0446, P0452, P0453, P0480, P0502 and P0503 (A/T only), P0601, P0602, P0604, P0606, P0621, P1133, P1441 or P1683 are not set.
2. The engine has run more than 30 seconds and less than 30 minutes.
3. The minimum IAT sensor parameter is more than 19°F (-7°C).
4. The ECT sensor parameter at start-up is less than 95°F (35°C).
5. The average airflow is more than 15 g/s.
6. The vehicle has traveled more than 0.5 miles at a speed of more than 25 MPH.

1. The calibrated amount of airflow has been met.
2. The calibrated amount of engine run time has been met.
3. The minimum ECT for Closed Loop of 104°F (40°C) has not been met.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Is the cooling system coolant low? If yes, go to drain & refill procedures in appropriate SPECIFICATIONS & DRIVE BELT ROUTING article under COOLING SYSTEM (MECHANICAL). If no, go to next step.
3. Check and verify the proper operation of the thermostat. For thermostat specifications, see appropriate SPECIFICATIONS & DRIVE BELT ROUTING article under COOLING SYSTEM (MECHANICAL). Did you find and correct the condition? If yes, go to step 14 .
4. Disconnect the ECT sensor harness connector. Inspect for corrosion on the ECT sensor terminals, improper or corroded terminals at the ECT harness connector and loose terminals in the ECT harness connector. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
5. Measure the voltage from the signal circuit of the ECT sensor to a good ground using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to next step. If no, go to step 8 .
6. Measure the voltage from the signal circuit of the ECT sensor to the low reference circuit of the ECT sensor using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to step 9 . If no, go to next step.
7. Check the ECT sensor low reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
8. Turn ignition switch to OFF position. Remove the ECT sensor. Place the sensor on a work surface away from any heat source. Allow the sensor to reach the ambient air temperature for 30-60 minutes. Observe and record the ambient air temperature of the vehicle environment using an accurate thermometer. Measure the resistance of the ECT sensor and record the value. Compare the resistance measurement of the ECT sensor to the ambient air temperature on the Temperature vs. Resistance table. See «TEMPERATURE VS. RESISTANCE»(ref-153397-S33004112412003040400000) table. Is the resistance measurement of the ECT sensor within the specified range? If yes, go to step 10 . If no, go to step 12 .
9. Check the ECT sensor low reference circuit for a high resistance or an open. Repair circuit as necessary. Did you find and correct the condition? If yes, go to next step. If no, go to 12 .
10. Install the ECT sensor. After installation of ECT sensor is complete, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
11. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Reinstall ECT sensor. After installation, go to step 14 .
13. Replace ECT sensor. After repair, go to next step.
14. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S09509974142003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using the scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301-P0304, P0335, P0336, P0440, P0442, P0446, P0452, P0453, P0480, P0502 and P0503 for A/T only, P0601, P0602, P0604, P0606, P0621, P1133, P1441 or P1683 are not set.
2. The engine has run more than 30 seconds and less than 30 minutes.
3. The minimum IAT sensor parameter is more than 19°F (-7°C).
4. The ECT sensor parameter at start up is less than 158°F (70°C).
5. The average air flow is more than 15 g/s.
6. The vehicle has traveled more than 1.5 miles (2.4 km) over 25 MPH.

1. The calibrated amount of engine run time has been met.
2. The calibrated amount of engine air flow has been met.
3. Enough air flow has entered the engine and the ECT has not risen to 167°F (75°C) for 30 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Is the cooling system coolant low? If yes, go to drain & refill procedures in appropriate SPECIFICATIONS & DRIVE BELT ROUTING article under COOLING SYSTEM (MECHANICAL). If no, go to next step.
3. Check and verify the proper operation of the thermostat. For thermostat specifications, see appropriate SPECIFICATIONS & DRIVE BELT ROUTING article under COOLING SYSTEM (MECHANICAL). Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
4. Disconnect the ECT sensor harness connector. Inspect for corrosion on the ECT sensor terminals, improper or corroded terminals at the ECT harness connector and loose terminals in the ECT harness connector. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
5. Measure the voltage from the signal circuit of the ECT sensor to a good ground using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to next step. If no, go to step 8 .
6. Measure the voltage from the signal circuit of the ECT sensor to the low reference circuit of the ECT sensor using a DMM. Is the voltage 4.8-5.2 volts? If yes, go to step 9 . If no, go to next step.
7. Check the ECT sensor low reference circuit for high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 11 .
8. Check the ECT sensor signal circuit for high resistance. Did you find and correct the condition? If yes, go to step 14 . If no, go to 11 .
9. Turn ignition switch to OFF position. Remove the ECT sensor. Place the sensor on a work surface away from any heat source. Allow the sensor to reach the ambient air temperature for 30-60 minutes. Observe and record the ambient air temperature of the vehicle environment using an accurate thermometer. Measure the resistance of the ECT sensor and record the value. Compare the resistance measurement of the ECT sensor to the ambient air temperature on the Temperature vs. Resistance table. See «TEMPERATURE VS. RESISTANCE»(ref-153397-S33004112412003040400000) table. Is the resistance measurement of the ECT sensor within the specified range? If yes, go to next step. If no, go to step 12 .
10. Install the ECT sensor. After installation, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
11. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
12. Replace ECT sensor. After repair, go to step 14 .
13. Replace the PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
14. Clear the DTCs using the scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S15916975742003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using scan tool, observe CAPTURE INFO. Does scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The engine has been running more than 200 seconds.
3. The engine speed is 1200-3400 RPM.
4. The TP angle is 10-40 percent.
5. The ECT sensor parameter is more than 158°F (70°C).
6. Conditions have been met for 2 seconds.

The PCM detects that the loop status parameter is open for 12.5 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine OFF. Command the HO2S 1 heater ON using a scan tool. Wait 15 seconds to allow the HO2S 1 heater current to stabilize. Observe the HO2S 1 heater current parameter using a scan tool. Is the HO2S 1 heater current parameter 0.217-1.56 amps? If yes, go to next step. If no, go to «DTC P0135: HO2S HEATER PERFORMANCE - SENSOR 1»(ref-153397-S18574627372003040400000) .
3. Start the engine. Allow engine to reach operating temperature. Operate the engine at 2000 RPM for 30 seconds. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter varying above and below 300-600 mV? If yes, go to next step. If no, go to step 5 .
4. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
5. Turn ignition switch to OFF position. Disconnect the HO2S 1 harness connector. Turn ignition switch to RUN position, engine OFF. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter more than 800 mV? If yes, go to next step. If no, go to step 7 .
6. Check the HO2S 1 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
7. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 1 harness connector on the engine harness side and the low signal circuit of the HO2S 1 harness connector on the engine harness side. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter 400-500 mV? If yes, go to step 9 . If no, go to next step.
8. Remove the jumper wire from the previous step. Check the HO2S 1 heater low control circuit for a short to one of the following circuits: The HO2S 1 low signal circuit. The HO2S 1 high signal circuit. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 14 .
9. Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire from the high signal circuit of the HO2S 1 harness connector on the engine harness side and ground. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter 400-500 mV? If yes, go to step 11 . If no, go to next step.
10. Remove the jumper wire from the previous step. Check the HO2S 1 low signal circuit for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
11. Measure the voltage from the high signal circuit of the HO2S 1 harness connector on the engine harness side to a good ground using a DMM. Is the voltage more one volt? If yes, go to next step. If no, go to step 13 .
12. Check the HO2S 1 low signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
13. Check the HO2S 1 high signal circuit for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
14. Check for an intermittent and for a poor connection at the HO2S 1. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
15. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
16. Replace HO2S 1. After repair, go to step 18 .
17. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
18. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S28222952242003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
19. Using scan tool, observe CAPTURE INFO. Does scan tool display any DTCs that have not been diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The ignition 1 signal parameter is more than 10 volts.
4. The fuel level sensor parameter is more than 10 percent.
5. The engine run time parameter is more than 10 seconds.
6. The engine is operating in closed loop.
7. The TP angle is 8-50 percent.
8. The MAP is more than 20 kPa.
9. The engine has been in the above conditions for 4 seconds.

The PCM detects that the HO2S 1 Voltage parameter is less than 52 mV for 125 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine above 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S 1 voltage is less than 52 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect the HO2S sensor harness connector. Turn ignition switch to RUN position, engine OFF. Using a DMM, measure the voltage of the HO2S 1 high signal circuit on the PCM side. Does the voltage measure 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 1 high signal circuit for a short to ground or a short to the HO2S 1 low signal circuit. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 1 is detecting a lean condition or may be contaminated. Check for the following conditions: HO2S connector water intrusion. Silicon-contaminated HO2S. An exhaust leak between the HO2S 1 and the engine. Vacuum leaks. Incorrect fuel pressure. Lean fuel injectors. Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 1 sensor. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the HO2S 1. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using a scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S00338371452003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

Rich Test Enable

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Ignition 1 signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 10 seconds.
6. The Loop Status parameter is closed.
7. The TP sensor parameter is between 8-50 percent.
8. The MAP sensor parameter is more than 20 kPa.
9. The above conditions are met for 4 seconds.

Decel Fuel Cutoff Test Enable

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The Loop Status parameter is closed.
3. The Decel. Fuel Cutoff is active for more than 2.5 seconds.

Rich Test

1. The PCM detects that the HO2S 1 parameter is more than 946 mV for 50 seconds. Or

Decel Fuel Cutoff Test

1. The PCM detects that the HO2S 1 parameter is more than 1042 mV for 50 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine at greater than 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S voltage is more than 946 millivolts? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S27346851352003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 1 sensor harness connector. Turn ignition switch to RUN position, engine off. Using a Digital Multimeter (DMM), measure the voltage of the HO2S 1 high signal circuit on the PCM side. Does the voltage measure 350-550 millivolts? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 1 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 1 is detecting a rich condition or may be contaminated. Check for HO2S connector water intrusion, silicone contaminated HO2S 1, fuel contaminated engine oil, incorrect fuel pressure, leaking fuel pressure regulator, or rich fuel injectors. Repair any conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 1 sensor. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace HO2S 1. When complete, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S27346851352003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 70°C (158°F).
3. The Ignition 1 signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 200 seconds.
6. The Engine Speed parameter is 1000-3500 RPM.
7. The MAP sensor parameter is 10-104 kPa.
8. The Air Flow Calculated parameter is more than 15 g/s.
9. The Loop Status parameter is closed.
10. The TP sensor parameter is 5-40 percent.
11. The EVAP Purge Solenoid command is more than 35 percent.
12. The above conditions are met for more than 60 seconds.

1. The PCM detects that the HO2S 1 rich-to-lean or lean-to-rich average response time is more than a calibrated value.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine at greater than 1200 RPM for two minutes. Using a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S 1 voltage is varying at greater than and less than the specified values of 350-550 millivolts? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S30059821052003040400000) . Does the scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 1 harness connector. Turn ignition switch to RUN position, engine off. Using a Digital Multimeter (DMM), measure the voltage of the HO2S 1 high signal circuit on the PCM side to a good ground. Does the voltage measure 350-550 millivolts? If yes, go to next step. If no, go to step 9 .
5. Turn ignition switch to OFF position. Connect a 3-amp fused jumper wire between the HO2S 1 harness connector high signal circuit and low signal circuit. Turn ignition switch to RUN position, engine off. Use scan tool in order to monitor HO2S 1 voltage for the sensor that applies to this DTC. Does the scan tool indicate that the HO2S 1 voltage is less than 20 millivolts? If yes, go to next step. If no, go to step 10 .
6. Turn ignition switch to OFF position. Remove the 3-amp fused jumper wire. Connect a test light between the ignition 1 voltage circuit and a good ground. DO NOT use the HO2S 1 heater low control. Turn ignition switch to RUN position, engine off. Does the test light illuminate? If yes, go to next step. If no, go to step 11 .
7. Connect a test light between the ignition 1 voltage circuit and the HO2S 1 heater low control circuit. Turn ignition switch to RUN position, engine off. Using a scan tool, command the HO2S 1 heater ON and OFF. Does the test light turn ON and OFF with each command? If yes, go to step 14 . If no, go to next step.
8. Does the test light remain illuminated with each command? If yes, go to step 12 . If no, go to step 13 .
9. Check the HO2S 1 high signal circuit for open, high resistance, short to ground or short to voltage. Did you find and correct the condition. If yes, go to step 19 . If no, go to step 16 .
10. Check the HO2S 1 low signal circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
11. Check the ignition 1 voltage circuit for an open, high resistance or short to ground. Replace ERLS fuse if necessary. Did you find and correct the condition? If yes, go to step 19 . If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
12. Check the HO2S 1 low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
13. Check the HO2S 1 low control circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
14. Inspect for incorrect use of silicone RTV sealant, fuel contamination, exhaust leak, improperly installed HO2S or damaged wiring. Did you find and correct the condition? If yes, go to step 19 . If no, go to next step.
15. Inspect for poor connections at the harness connector of the HO2S 1. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 17 .
16. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
17. Replace HO2S 1. After repair, go to step 19 .
18. Replace PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
19. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S30059821052003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
20. Using a scan tool, observe the stored information, CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Ignition 1 Signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Air Flow Calculated parameter is more than 3 grams per second (g/s).
6. The TP sensor parameter is between 8-56 percent.
7. The MAP Sensor parameter is more than 20 kPa.
8. The Engine Run Time parameter is more than 30 seconds.

The PCM detects that the HO2S 1 parameter is 400-500 mV for 125 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine OFF. Command the HO2S 1 heater ON using a scan tool. Wait 15 seconds to allow the HO2S 1 heater current to stabilize. Observe the HO2S 1 heater current parameter with a scan tool. Is the HO2S 1 heater current parameter 0.217-1.56 amps? If yes, go to next step. If no, go to «DTC P0135: HO2S HEATER PERFORMANCE - SENSOR 1»(ref-153397-S18574627372003040400000) .
3. Start the engine. Allow the engine to reach operating temperature. Operate the engine at 2000 RPM for 30 seconds. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter varying above and below 400-500 mV? If yes, go to next step. If no, go to step 5 .
4. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
5. Turn ignition switch to OFF position. Disconnect the HO2S 1 harness connector. Turn ignition switch to RUN position, engine OFF. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter more than 800 mV? If yes, go to next step. If no, go to step 7 .
6. Check the HO2S 1 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
7. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 1 harness connector on the engine harness side and the low signal circuit of the HO2S 1 harness connector on the engine harness side. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter 400-500 mV? If yes, go to step 9 . If no, go to next step.
8. Remove the jumper wire from the previous step. Check the HO2S 1 heater low control circuit for a short to one of the following circuits: The HO2S 1 low signal circuit. The HO2S 1 high signal circuit. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 14 .
9. Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire from the high signal circuit of the HO2S 1 harness connector on the engine harness side and ground. Observe the HO2S 1 voltage parameter using a scan tool. Is the HO2S 1 voltage parameter 400-500 mV? If yes, go to step 11 . If no, go to next step.
10. Remove the jumper wire from the previous step. Check the HO2S 1 low signal circuit for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
11. Measure the voltage from the high signal circuit of the HO2S 1 harness connector on the engine harness side to a good ground using a DMM. Is the voltage more than one volt? If yes, go to next step. If no, go to step 13 .
12. Check the HO2S 1 low signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 10 .
13. Inspect for improper use of silicone RTV sealant, fuel contamination, exhaust leak, improperly installed HO2S 1 or damaged wiring. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
14. Check for an intermittent and for a poor connection at the HO2S 1. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
15. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
16. Replace HO2S 1. After repair, go to step 18 .
17. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
18. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S03440087942003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
19. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The Ignition 1 signal parameter is 10-17 volts.
3. The ECT Sensor parameter is more than 158°F (70°C).
4. The Air Flow Calculated parameter is less than 16 g/s.
5. The Fuel Level Sensor parameter is more than 10 percent.
6. The Engine Run Time parameter is more than 60 seconds.

1. The PCM detects that the HO2S 1 heater current is less than 0.217 amps or more than 1.56 amps.
2. The above condition is met for 200 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Use a scan tool in order to clear the MIL and the DTC.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine OFF. Command the HO2S 1 heater ON using scan tool. Wait 15 seconds to allow the HO2S 1 heater current to stabilize. Observe the HO2S 1 heater current parameter. Is the HO2S 1 heater current parameter 0.217-1.56 amps? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Inspect the AUTO TRANS fuse (Cavalier & Grand Am) or ERLS fuse (Alero & Sunfire). Is the AUTO TRANS or ERLS fuse open? If yes, go to next step. If no, go to step 6 .
5. Check the ignition 1 voltage circuit for a short to ground. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 8 .
6. Disconnect the HO2S 1 harness connector. Turn ignition switch to RUN position, engine OFF. Probe the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 17 .
7. Connect a test light between the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side and the HO2S heater low control circuit of the HO2S harness connector on the engine harness side. Using scan tool, command the HO2S 1 heater ON and OFF. Does the test light turn ON and OFF with each command? If yes, go to step 9 . If no, go to step 10 .
8. Check the ignition 1 voltage circuit on the sensor side of the HO2S 1 connector for a short to ground. Is the sensor shorted to ground? If yes, go to step 18 . If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
9. Measure the resistance of the following circuits using a DMM: HO2S heater low control circuit. Ignition 1 voltage circuit. Is the resistance of either circuit more than 3 ohms? If yes, go to step 16 . If no, go to step 14 .
10. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step 12 .
11. Check the HO2S heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 15 .
12. Check the HO2S heater low control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
13. Check the HO2S heater low control circuit for an open. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 15 .
14. Check for an intermittent and for a poor connection at the HO2S. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 18 .
15. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
16. Repair the circuit with high resistance. After repair, go to step 20 .
17. Repair the open in the ignition 1 voltage circuit. After repair, go to step 20 .
18. Replace the HO2S 1. After repair, go to step 20 .
19. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
20. Were you sent to this diagnostic from DTC P0134? If yes go to step 18 under DTC P0134: HO2S CIRCUIT - INSUFFICIENT ACTIVITY SENSOR 1 diagnostic procedures. If no, go to next step.
21. Replace the AUTO TRANS or ERLS fuse if necessary. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S19726768622003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
22. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed. If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Ignition 1 signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 10 seconds.
6. The Loop Status parameter is closed.
7. The TP Sensor parameter is between 8-50 percent for 3.8 seconds.
8. The MAP sensor parameter is more than 20 kPa.
9. The above conditions are met for 4 seconds.

The PCM detects that the HO2S 2 parameter is less than 43 mV for 150 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine at greater than 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 2 voltage parameter. Does the scan tool indicate that the HO2S 2 voltage is less than 43 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S40714450912003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 2 sensor harness connector. Turn ignition switch to RUN position, engine off. Measure the voltage of the HO2S 2 high signal circuit on the PCM side. Does the voltage measure within 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 2 high signal circuit for a short to ground or a short to the low signal circuit. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 2 may be detecting a lean exhaust condition. Check for one of the following conditions: HO2S connector water intrusion. An exhaust leak between the HO2S 2 and engine. Vacuum leaks. Incorrect fuel pressure. Lean fuel injectors. An inaccurate MAF sensor. Repair any conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 2 sensor. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace HO2S 2. When complete, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S40714450912003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Ignition 1 signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 10 seconds.
6. The Loop Status parameter is closed.
7. The TP sensor parameter is between 8-50 percent for 3.8 seconds.
8. The MAP sensor parameter is more than 20 kPa.
9. The above conditions are met for 4 seconds.

HO2S 2 voltage is more than 1042 mV for 50-75 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine at greater than 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 2 voltage parameter. Does the scan tool indicate that the HO2S 2 voltage is more than 994 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S24921095802003040400000) . Does the scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 2 sensor harness connector. Turn ignition switch to RUN position, engine off. Using a Digital Multimeter (DMM), measure the voltage of the HO2S 2 high signal circuit on the PCM side. Does the voltage measure 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 2 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 2 is detecting a rich exhaust condition or may be contaminated. Check for HO2S connector water intrusion, a silicone contaminated HO2S 2, fuel contaminated engine oil, incorrect fuel pressure, leaking fuel pressure regulator or rich fuel injectors. Repair any of the conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 2. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace HO2S 2. When complete, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S24921095802003040400000) . Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0201-P0204, P0300, P0301-P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The battery voltage is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The engine run time is more than 10 seconds.
6. The engine is operating in closed loop.
7. The TP angle is 8-50 percent for 3.8 seconds.
8. The MAP sensor parameter is more than 25 kPa.

The PCM detects that the HO2S 2 parameter is more than 1042 mV for 50 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine above 1200 RPM for 2 minutes. Observe the HO2S 2 voltage parameter using the scan tool. Does the scan tool indicate that the HO2S 2 voltage is more than 1042 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR SETTING DTC»(ref-153397-S19581127062003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect the HO2S 2 sensor harness connector. Turn ignition switch to RUN position, engine OFF. Measure the voltage of the HO2S 2 high signal circuit on the PCM side using the DMM. Does the voltage measure 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 2 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 2 is detecting a rich exhaust condition or may be contaminated. Check for one of the following conditions: HO2S connector water intrusion. A silicone contaminated HO2S 2. Fuel contaminated engine oil. Incorrect fuel pressure. A leaking fuel pressure regulator. Rich fuel injectors. Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 2. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace HO2S. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S42782233792003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0141, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Ignition 1 signal parameter is more than 10 volts.
4. The Fuel Level sensor parameter is more than 10 percent.
5. The Engine Run Time parameter is more than 30 seconds.
6. The Air Flow Calculated parameter is more than 5.5 g/s for 70 seconds.
7. The TP sensor parameter is 8-56 percent.
8. The MAP Sensor parameter is more than 20 kPa.
9. The Loop Status parameter is closed.

The PCM detects that the HO2S 2 parameter is 425-473 mV for 125 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine OFF. Using the scan tool, command the HO2S 2 heater ON. Wait 15 seconds to allow the HO2S 2 heater current to stabilize. Observe the HO2S 2 heater current parameter using a scan tool. Is the HO2S 2 heater current parameter 0.217-1.56 amps? If yes, go to next step. If no, go to «DTC P0141: HO2S HEATER PERFORMANCE - SENSOR 2»(ref-153397-S11042258162003040400000) .
3. Start the engine. Operate the engine at normal operating temperature. Operate the engine at 2000 RPM for 30 seconds. Quickly cycle the throttle from closed throttle to wide open throttle 3 times, while observing the HO2S 2 voltage parameter using a scan tool. Did the HO2S 2 change more than 200 mV? If yes, go to next step. If no, go to step 5 .
4. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S23406302542003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
5. Turn ignition switch to OFF position. Disconnect the HO2S 2 harness connector. Turn ignition switch to RUN position, engine off. Observe the HO2S 2 voltage parameter using a scan tool. Is the HO2S 2 voltage parameter more than 800 mV? If yes, go to next step. If no, go to step 7 .
6. Check the HO2S 2 high signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
7. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 2 harness connector on the engine harness side and the low signal circuit of the HO2S 2 harness connector on the engine harness side. Observe the HO2S 2 voltage parameter using a scan tool. Is the HO2S 2 voltage parameter 400-500 mV? If yes, go to step 9 . If no, go to next step.
8. Remove the jumper wire from the previous step. Check the HO2S 2 heater low control circuit for a short to one of the following circuits: The HO2S 2 low signal circuit. The HO2S 2 high signal circuit. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 14 .
9. Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire from the high signal circuit of the HO2S 2 harness connector on the engine harness side and ground. Observe the HO2S 2 voltage parameter using a scan tool. Is the HO2S 2 voltage parameter 400-500 mV? If yes, go to step 11 . If no, go to next step.
10. Remove the jumper wire from the previous step. Check the HO2S 2 low signal circuit for an open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
11. Measure the voltage from the high signal circuit of the HO2S 2 harness connector on the engine harness side to a good ground using a DMM. Is the voltage more than one volt? If yes, go to next step. If no, go to step 13 .
12. Check the HO2S 2 low signal circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
13. Check the HO2S 2 high signal circuit for open. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 15 .
14. Check for an intermittent and for a poor connection at the HO2S 2. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 16 .
15. Check for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 18 . If no, go to step 17 .
16. Replace the HO2S 2. After repair, go to step 18 .
17. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
18. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S23406302542003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
19. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0300, P0301-P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0506, P0507, P0601, P0602, P1441 or P1621 are not set.
2. The Ignition 1 signal parameter is 10-17 volts.
3. The ECT sensor parameter is more than 158°F (70°C).
4. The Air Flow Calculated parameter is less than 40 g/s.
5. The Fuel Level sensor parameter is more than 10 percent.
6. The Engine Run Time parameter is more than 60 seconds.

1. The PCM detects that the HO2S 2 heater current is less than 0.217 amps or more than 1.56 amps.
2. The above condition is met for 200 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine OFF. Using the scan tool, command the HO2S 2 heater ON. Wait 15 seconds to allow the HO2S 2 heater current to stabilize. Observe the HO2S 2 heater current parameter. Is the HO2S 2 heater current parameter 0.217-1056 amps? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S02755858882003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Inspect the O2 HTR fuse (Cavalier & Sunfire) or ERLS fuse (Alero & Grand Am). Is the O2 HTR or ERLS fuse open? If yes, go to next step. If no, go to step 6 .
5. Check the ignition 3 voltage circuit for a short to ground. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 8 .
6. Disconnect the HO2S 2 harness connector. Turn ignition switch to RUN position, engine off. Probe the ignition 3 voltage circuit of the HO2S harness connector on the engine harness side using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 17 .
7. Connect a test light between the ignition 1 voltage circuit of the HO2S harness connector on the engine harness side and the HO2S heater low control circuit of the HO2S harness connector on the engine harness side. Command the HO2S 2 heater ON and OFF using a scan tool. Does the test light turn ON and OFF with each command? If yes, go to step 9 . If no, go to step 10 .
8. Check the ignition 3 voltage circuit on the sensor side of the HO2S connector for a short to ground. Is the sensor shorted to ground? If yes, go to step 18 . If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
9. Measure the resistance of the following circuits using a DMM: HO2S heater low control circuit. Ignition 3 voltage circuit. Is the resistance of either circuit more than 3 ohms? If yes, go to step 16 . If no, go to step 14 .
10. Does the test light remain illuminated with each command? If yes, go to next step. If no, go to step 12 .
11. Check the HO2S heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 15 .
12. Check the HO2S heater low control circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
13. Check the HO2S heater low control circuit for an open. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 15 .
14. Check for an intermittent and for a poor connection at the HO2S. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
15. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 20 . If no, go to step 19 .
16. Repair the circuit with high resistance. After repair, go to step 20 .
17. Repair the open in the ignition 3 voltage circuit. After repair, go to step 20 .
18. Replace the HO2S 2. After repair, go to step 20 .
19. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
20. Were you sent to this diagnostic from DTC P0140? If yes, go to step 18 in DTC P0140: HO2S 2 CIRCUIT - INSUFFICIENT ACTIVITY - SENSOR 2. If no, go to next step.
21. Replace the O2 HTR fuse (Cavalier & Sunfire) or ERLS fuse (Alero & Grand Am) if necessary. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S02755858882003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
22. Using the scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0201-P0204, P0300, P0301-P0304, P0325, P0341, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133 or P1441 are not set.
2. The ECT sensor parameter is 140-239°F (60-115°C).
3. The IAT sensor parameter is -13 to 239°F (-25 to 115°C).
4. The MAP sensor parameter is greater than 4.0 psi (28 kPa).
5. The vehicle speed is less than 82 MPH.
6. The engine speed is 550-3600 RPM.
7. The BARO sensor parameter is more than 10.3 psi (72 kPa).
8. The fuel ethanol composition is less than 88 percent.
9. The Fuel Level sensor parameter is more than 9.8 percent.

The fuel trim index is at more than 20 percent.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Install scan tool. Review the Freeze Frame/Failure Records and record the displayed data for this DTC. Select Fuel Trim Data parameter. Start the engine and observe the Fuel Trim Index. Does the scan tool indicate that the Fuel Trim Index is more than 20 percent? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S32129527992003040400000) .
3. Operate the engine at idle. Using scan tool, observe the HO2S parameters. Does the scan tool indicate that the values are within 200-800 mV and fluctuating? If yes, go to next step. If no, go to step 5 .
4. Turn engine off. Visually and physically inspect the following: Vacuum hoses for splits, kinks, and proper connections. Fuel pressure. If fuel pressure is too low this DTC may set. Check for fuel contamination. Did you find and correct the condition? If yes, go to step 8 . If no, go to step 7 .
5. Turn ignition switch to OFF position. Turn ignition switch to RUN position, engine OFF. Observe the Manifold Absolute Pressure (MAP) sensor pressure parameter using a scan tool. See «ALTITUDE VS. BAROMETRIC PRESSURE»(ref-153397-S09237067502003042200000) table. The MAP sensor pressure should be within the range specified for your altitude. Does the MAP indicate the correct barometric pressure? If yes, go to next step. If no, go to «DTC P0105: MANIFOLD ABSOLUTE PRESSURE SENSOR PERFORMANCE/RANGE»(ref-153397-S36390896992003040400000) .
6. Turn ignition switch to OFF position. Inspect for the following conditions: The O2S for proper installation. Ensure harness connectors and wires are secured and not contacting the exhaust system. A short between the signal circuit and low reference circuit. Did you find and correct the condition? If yes, go to step 8 . If no, diagnose fuel system. See «FUEL SYSTEMS (GASOLINE)»(ref-153404-S11758687802003040400000) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
7. Operate the engine at idle and check for missing, loose, or leaking exhaust components. Check for vacuum leaks at intake manifold, throttle body and injector "O" rings. Check the air induction system and air intake ducts for leaks. Check crankcase ventilation system for leaks. Did you find and correct the condition? If yes, go to next step. If no, check for engine mechanical problem. See appropriate article in ENGINES.
8. Using the scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S17121332742003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
9. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. The system will go lean if an injector is not supplying enough fuel.
2. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel.
3. Using a scan tool, review the Failure Records. If an intermittent condition is suspected, see «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

ALTITUDE VS. BAROMETRIC PRESSURE (1)

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0201-P0204, P0300, P0301-P0304, P0325, P0341, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133 or P1441 are not set.
2. The ECT sensor parameter is 140-239°F (60-115°C).
3. The IAT sensor parameter is -13 to 239°F (-25 to 115°C).
4. The MAP sensor parameter is at greater than 4.0 psi (28 kPa).
5. The vehicle speed is less than 82 MPH.
6. The engine speed is 550-3600 RPM.
7. The BARO sensor parameter is more than 10.3 psi (72 kPa).
8. The fuel ethanol composition is less than 88 percent.
9. The Fuel Level sensor parameter is more than 9.8 percent.

1. The fuel trim index is less than -46 percent.
2. The diagnostics have determined that a rich condition was not due to excessive vapor.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Connect scan tool. Review the Freeze Frame/Failure Records and record displayed data for this DTC. Select FUEL TRIM DATA parameter. Start the engine and observe the FUEL TRIM INDEX. Does the scan tool indicate that the fuel trim index is less than -46 percent? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S32108661212003040400000) .
3. Start the engine. Allow the engine to reach operating temperature. Put the transmission in PARK or NEUTRAL position. Turn all accessories OFF. Allow engine to idle. Observe the Manifold Absolute Pressure (MAP) sensor. Parameter using a scan tool. Is the MAP sensor parameter within the specified range? If yes, go to next step. If no, go to «DTC P0105: MANIFOLD ABSOLUTE PRESSURE SENSOR PERFORMANCE/RANGE»(ref-153397-S36390896992003040400000) .
4. Operate the engine at idle. Observe the oxygen sensor parameters using a scan tool. Does the scan tool indicate the values are 200-800 mV and fluctuating? If yes, go to next step. If no, go to step 6 .
5. Turn engine off. Visually and physically inspect vacuum hoses for splits, kinks, and proper connections. Check the air intake duct for being collapsed or restricted. Check the air filter for being dirty or restricted or for objects blocking throttle body. Repair as necessary. After repair, go to step 8 .
6. Turn engine off. Inspect the HO2S for proper installation. Ensure harness connectors and wires are secured and not contacting the exhaust system. Did you find and correct the condition? If yes, go to step 8 . If no, diagnose fuel system. See «FUEL SYSTEMS (GASOLINE)»(ref-153404-S11758687802003040400000) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
7. Check for excessive fuel in the crankcase. Check evaporative emissions control system and fuel pressure regulator for proper operation. Ensure that all injectors are functioning properly. Perform the fuel injector balance test. See «FUEL INJECTOR BALANCE TEST»(ref-153404-S30411575462003040400000) under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Did you find and correct the condition? If yes, go to next step. If no, diagnose engine mechanical problem. See appropriate article in ENGINES.
8. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S06212317412003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
9. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. Fuel contamination, such as water and alcohol, will affect the fuel trim.
2. The system will go rich if the injectors are supplying too much fuel.
3. Review the Failure Records using a scan tool. If intermittent condition is suspected, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. The engine is running.
2. The ignition voltage is 9-18 volts.

1. The PCM detects an incorrect voltage on the fuel injector control circuit.
2. The condition exists for 30 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S12943231102003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S07989363202003040400000) .
3. Turn ignition switch to OFF position. Remove the air cleaner outlet resonator. Disconnect the fuel injector harness connector. Turn ignition switch to RUN position, engine off. Probe the ignition 1 voltage circuit of the fuel injector using a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to 10 .
4. Connect the Injector Test Light (J 34730-405) between the control circuit and the ignition 1 voltage circuit of the fuel injector. Start the engine. Does the test light flash? If yes, go to step 8 . If no, go to next step.
5. Does the test light remain illuminated at all times? If yes, go to step 7 . If no, go to next step.
6. Check the control circuit of the fuel injector for an open and for a short to voltage. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 9 .
7. Check the control circuit of the fuel injector for a short to ground. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
8. Check for an intermittent and for a poor connection at the fuel injector. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 11 .
9. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 13 . If no, go to step 12 .
10. Repair the open or short to ground in the ignition 1 voltage circuit of the fuel injector. Replace the fuse as necessary. After repair, go to step 13 .
11. Replace the affected fuel injector. After repair, go to step 13 .
12. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
13. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S12943231102003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
14. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. Performing the Fuel Injector Coil test may help isolate an intermittent condition. See «FUEL INJECTOR COIL TEST»(ref-153404-S39822063482003040400000) under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
2. For an intermittent condition, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTC P0105, P0107, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0336, P0340, P0341, P0502, P0503, P0506, P0507, P0601, P0742, P1133 or P1621 are not set.
2. The engine speed is 469-6400 RPM.
3. The battery voltage is 9-17 volts.
4. The ECT sensor parameter is 20-254°F (-7 to 123°C).
5. The engine has been running for more than 5 seconds.
6. The TP sensor has not increased more than 8 percent in one second.
7. The TP has not decreased more than 1.5 percent in 1 second.

The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Start the engine. Allow engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the Misfire counters using the scan tool. Are any of the Misfire Current counters incrementing? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
3. Are any other DTCs set? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
4. Can any abnormal engine noise be heard? If yes, diagnose engine mechanical problem. See appropriate article in ENGINES. If no, go to next step.
5. Start and idle the engine. Compare the Manifold Absolute Pressure (MAP) voltage indicated by the scan tool with the typical scan data. Is the indicated value more than the typical value? If yes, go to «DTC P0108: MANIFOLD ABSOLUTE PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE»(ref-153397-S09830118232003040400000) . If no, go to next step.
6. Inspect the following components: The vacuum hoses and seals for splits, restrictions, and improper connections. The crankcase ventilation system for vacuum leaks. The PCM grounds for corrosion and loose connections. The exhaust system for restrictions. The fuel for contamination. Did you find and correct the condition? If yes, go to step 20 . If no, go to next step.
7. Turn ignition switch to OFF position. Remove the fuel pump relay. Remove the ignition coil housing assembly, keeping the Ignition Control Module (ICM) assembly connected to the harness connector. Connect a jumper wire between the top of the IC module and a good ground. Install the Ignition System Diagnosis Harness (J 36012-A), or equivalent. Install a Spark Tester (J 26792), or equivalent, on the No. 1 spark plug jumper wire. Ground the No. 4 spark plug jumper wire. The No. 4 wire is the companion to No. 1. Crank the engine with the remaining spark plug wires connected. Repeat the above steps by installing the spark tester on No. 4 and grounding No. 1. Do the same for the No. 2 and the No. 3 spark plugs. Ensure the companion wire is grounded. Does the spark tester spark on all cylinders? If yes, go to next step. If no, go to «IGNITION SYSTEMS»(ref-153404-S01773795512003040400000) in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
8. Remove the spark plug from the cylinder that indicated a misfire. Inspect the spark plug. Does the spark plug appear to be OK? If yes, go to next step. If no, go to step 10 .
9. Exchange the suspected spark plug with another cylinder that is operating properly. Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug? If yes, go to step 16 . If no, go to step 13 .
10. Is the spark plug oil or coolant fouled? If yes, diagnose engine mechanical problem. See appropriate article in ENGINES. If no, go to next step.
11. Is the spark plug gas fouled? If yes, go to step 14 . If no, go to next step.
12. Did the spark plug show any signs of being cracked, worn, or improperly gapped? If yes, go to step 14 . If no, go to next step.
13. Perform the fuel injector coil test. Go to «FUEL INJECTOR COIL TEST»(ref-153404-S39822063482003040400000) under FUEL SYSTEMS in SYSTEM & COMPONENT TESTS - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Did you find and correct the condition? If yes, go to step 17 . If no, diagnose engine mechanical problem. See appropriate article in ENGINES.
14. Perform the fuel system diagnosis. Go to «FUEL SYSTEM DIAGNOSIS (GASOLINE)»(ref-153407-S03416773192003120300000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Did you find and correct the condition? If yes, go to step 17 . If no, diagnose engine mechanical problem. See appropriate article in ENGINES.
15. Replace or gap the spark plug. After repair, go to step 17 .
16. Replace the faulty spark plug. After repair, go to step 17 .
17. Was the customer concern the MIL flashing? If yes, go to next step. If no, go to step 19 .
18. Operate the vehicle at 2500 RPM for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420 as specified in the supporting text. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S11224207852003040400000) in DTC P0420: TWC SYSTEM - LOW EFFICIENCY. Does the DTC run and pass? If yes, go to next step. If no go to «DTC P0420: TWC SYSTEM - LOW EFFICIENCY»(ref-153397-S40331374982003040400000) .
19. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S39692629562003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
20. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTC P0105, P0107, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0335, P0341, P0502, P0503, P0506, P0507, P0601, P0742, P1133 or P1621 are not set.
2. The engine speed is 469-6400 RPM.
3. The ignition voltage is 9-17 volts.
4. The ECT sensor parameter is 20-254°F (-7 to 123°C).
5. The engine has been running more than 5 seconds.
6. The TP has not increased more than 8 percent in one second.
7. The TP has not decreased more than 1.5 percent in one second.

The PCM is detecting a crankshaft rotation speed variation indicating a single cylinder misfire rate sufficient to cause emissions levels to exceed mandated standard.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Start the engine. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the misfire counters using the scan tool. Are any of the misfire current counters incrementing? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
3. Are any DTCs other than DTC P0300 set? If yes, go to step 10 . If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
4. Can any abnormal engine noise be heard? If yes, diagnose engine mechanical problem. See appropriate article in ENGINES. If no, go to next step.
5. Turn ignition switch to OFF position. Remove the fuel pump relay. Remove the ignition coil housing assembly. Connect a jumper wire between the IC module and a good ground. Connect the Ignition System Diagnostic Harness (J 36012-A), or equivalent. Install Spark Tester (J 26792), or equivalent, on the affected cylinder spark plug jumper wire. Ground the companion to the affected cylinder spark plug jumper wire. Crank the engine with the remaining spark plug jumper wires connected. Does the spark tester spark? If yes, go to step 7 . If no, go to next step.
6. Inspect the affected cylinder spark plug boot for a missing or damaged ignition coil spring. Did you find and correct the condition? If yes, go to step 16 . If no, go to step 15 .
7. Remove the spark plug from the cylinder that indicated a misfire. Inspect the spark plug. Does the spark plug appear to be okay? If yes, go to next step. If no, go to step 9 .
8. Turn ignition switch to OFF position. Remove the spark plug boots from the affected coil. Inspect the affected cylinder boot for damage or missing spring, and replace as necessary. Did you find and correct the condition? If yes, go to step 10 . If no, go to next step.
9. Is the spark plug oil or coolant fouled? If yes, diagnose engine mechanical problem. See appropriate article in ENGINES. If no, go to step 11 .
10. Is the spark plug gas fouled? If yes, go to step 12 . If no, go to step 11 .
11. Does the spark plug show any signs of being cracked, worn, or improperly gapped? If yes, go to step 13 . If no, go to next step.
12. Perform injector coil test and injector balance test procedure. See «FUEL INJECTOR COIL TEST»(ref-153404-S39822063482003040400000) under FUEL SYSTEMS (GASOLINE) in SYSTEM & COMPONENT TESTING 2.2L - ALERO, CAVALIER, GRAND AM & SUNFIRE article. Did you find and correct the condition? If yes, go to step 16 . If no, diagnose engine mechanical problem. See appropriate article in ENGINES.
13. Replace or gap the spark plug. If an improper gap is found, be sure to gap the spark plugs using a wire type gauge. After repair, go to step 16 .
14. Replace the faulty spark plug. After repair, go to step 16 .
15. Replace ignition coil housing. After repair, go to step 16 .
16. Was the customer concern the MIL flashing? If yes, go to next step. If no, go to step 18 .
17. Operate the vehicle at 2500 RPM for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420 as specified in the supporting text. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S11224207852003040400000) in DTC P0420: TWC SYSTEM - LOW EFFICIENCY. Does the DTC run and pass? If yes, go to next step. If no, go to «DTC P0420: TWC SYSTEM - LOW EFFICIENCY»(ref-153397-S40331374982003040400000) .
18. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S37063008592003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
19. Using scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0117, P0118, P0122, P0123 or P0327 are not set.
2. The engine run time is more than 20 seconds.
3. The ECT sensor parameter is more than 158°F (70°C).
4. The engine speed is 1800-6400 RPM.
5. The MAP sensor parameter is more than 55 kPa.

The PCM detects a malfunction in the KS diagnostic circuitry that will not allow proper diagnosis of the KS system.

1. PCM will illuminate the Malfunction Indicator Light (MIL) during the second consecutive trip in which the diagnostic test has run and failed.
2. PCM will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

1. PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has run and passed.
2. The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
3. Use scan tool to clear the DTCs.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close as possible to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S27437431242003040400000) . Did the DTC fail this ignition? If yes, go to next step. If no, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
3. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
4. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S27437431242003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
5. Use a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0117, P0118, P0122 or P0123 are not set.
2. The engine run time is more than 20 seconds.
3. The ECT sensor parameter is more than 158°F (70°C).
4. The engine speed is 1800-6400 RPM.
5. The MAP sensor parameter is more than 55 kPa.
6. The ignition voltage is more than 10 volts.

The PCM detects that the KS signal is outside of the assigned voltage range, or the KS signal is not present.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Observe the Freeze Frame/Failure Records data for this DTC. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S40353699822003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition cycle? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S36118545662003040400000) .
3. Turn ignition switch to OFF position. Disconnect the Knock Sensor (KS) harness connector. Set the Digital Multi-Meter (DMM) to the ohms scale. Measure the resistance from the KS signal circuit on the sensor side of the KS harness connector to a good ground using the DMM. Measure the resistance from the KS low reference circuit on the sensor side of the KS harness connector to a good ground. Does the DMM display OL for both circuits? If yes, go to next step. If no, go to step 8 .
4. Connect a DMM between the signal circuit of the KS and the low reference circuit of the KS on the sensor side of the KS harness connector. Set the DMM to the AC scale. Start the engine. Idle the engine for 2 minutes with the ECT above 180°F (82°C). Observe the DMM while accelerating the engine from idle to 3000 RPM. Is the voltage below the 20 mV at idle and above 80 mV at 3000 RPM? If yes, go to next step. If no, go to step 8 .
5. Turn ignition switch to RUN position, engine OFF. Set the DMM to the DC scale. On the PCM side of the KS harness connector, measure the voltage from the KS signal circuit to a good ground using a DMM. On the PCM side of the KS harness connector, measure the voltage from the KS low reference circuit to a good ground using a DMM. Is the voltage more than 4.5 volts on any circuit? If yes, go to next step. If no, go to step 7 .
6. Turn ignition switch to OFF position. Disconnect the PCM harness connectors. Check the KS signal circuit and the KS low reference circuit for a short to voltage. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
7. Turn ignition switch to OFF position. Disconnect the PCM harness connectors. Check the KS signal circuit and the KS low reference circuit for an open, high resistance, or short to ground. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 9 .
8. Check for an intermittent and for a poor connection at the KS. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 10 .
9. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 12 . If no, go to step 11 .
10. Replace KS. After repair, go to step 12 .
11. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
12. Using scan tool, clear the DTCs. Turn the ignition OFF for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S40353699822003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
13. Use scan tool to observe the, CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. Inspect the KS for physical damage. A KS that is dropped or damaged may cause a DTC to set.
2. Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material.
3. The KS must be clear of hoses, brackets, and engine electrical wiring.
4. For an intermittent condition, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. The engine is running.
2. DTC P0341 is not set.

The CKP resync counter goes more than 15 times within 4 minutes and 15 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Attempt to start the engine. Does the engine start and run? If yes, go to next step. If no, go to «NO-START DIAGNOSIS»(ref-152426-S09964719712003032400000) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S17521586352003040400000) . Does the DTC fail this ignition? If yes, go to next step. If no, go to step 5 .
4. With engine running, wiggle PCM and CKP harness connectors and related circuits while listening for the engine to stumble. Does the engine stumble? If yes, go to step 6 . If no, go to step 7 .
5. Operate any non-engine related electronic component on the vehicle. Observe the MED. RESOLUTION RESYNC COUNTER using the scan tool. Does the Med. Resolution Resync Counter on the scan tool increment while operating any non-engine related electronic components? If yes, go to step 9 . If no, go to step 4 .
6. Turn ignition switch to OFF position. Check for an intermittent and for a poor connection at the connector that caused the engine to stumble. After repair, go to step 14 .
7. Did the MIL illuminate in step 3 ? If yes, go to next step. If no, go to step «DIAGNOSTIC AIDS»(ref-153397-S37038805222003040400000) .
8. Turn ignition switch to OFF position. Check for rubbed-through wire insulation or for pinched wiring in the PCM or CKP sensor circuits. Repair wiring as necessary. Did you complete the repair? If yes, go to step 14 . If no, go to step 10 .
9. Turn ignition switch to OFF position. Repair circuitry of the malfunctioning or interfering component. Move any wiring that is causing the interference away from the CKP wiring harness. After repair, go to step 14 .
10. Replace CKP sensor. Visually inspect CKP sensor for the following conditions: Any physical damage. A loose or improper installation. Any wiring routed too closely to the secondary ignition components. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
11. Visually inspect the CKP reluctor wheel for damage or looseness. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
12. Replace the CKP sensor. Idle the engine for 5 minutes or until the MIL illuminates. Did the MIL illuminate? If yes, go to next step. If no, go to step 14 .
13. Replace PCM. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, idle the engine for 5 minutes or until the MIL illuminates. Did the MIL illuminate? If yes, go to «DIAGNOSTIC AIDS»(ref-153397-S37038805222003040400000) . If no, go to next step.
14. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S17521586352003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using a scan tool, observe CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. If the complaint was Engine Cranks But Will Not Run, you may set DTC P0336 when attempting to start the engine more than 15 times, and ignition is not turned OFF between attempts.
2. The following conditions may cause this DTC to set: Poor connection or poor terminal tension at the sensor, crankshaft reluctor wheel damage or improper installation, excessive air gap between CKP sensor and reluctor wheel, engine running out of fuel, or foreign material passing between sensor and reluctor wheel.
3. Excess crankshaft end play causes the CKP sensor reluctor wheel to move out of alignment with the CKP sensor. This could result in any one of the following: A no start, a start and stall or erratic performance.
4. For an intermittent, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The engine is running.

The PCM does not detect any change in the CMP sensor signal for 35 crankshaft revolutions, 70 combustion events, when Manifold Absolute Pressure (MAP) is at 55 kPa or more.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Install the scan tool. Start and idle the engine. Using a scan tool, monitor the CMP ACTIVE COUNTER parameter. Does the scan tool indicate the CMP active counter is incrementing? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S13430697522003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC reset? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S39504377282003040400000) .
4. Turn ignition switch to OFF position. Disconnect Ignition Control Module (ICM) harness connector. Using Connector Test Adaptor Kit (J 35616-A), or equivalent, jumper each wire from the ICM harness connector to the ICM except the CMP circuit wire. Touch the CMP circuit at the ICM with one lead of the Digital Multimeter (DMM), and the other lead to a ground. Select the DC voltage duty cycle option on the DMM. Start the engine. Is the duty cycle within 45-55 percent? If yes, go to step 6 . If no, go to next step.
5. Turn ignition switch to OFF position. Remove jumper wires from ICM. Remove ICM from Ignition Coil Cassette. Remove interconnect from in-between the Coil Cassette and ICM. Inspect interconnect for a poor connection at coil cassette or at ICM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 7 .
6. Check the CMP signal circuit for the following conditions: An open. High resistance. A short to ground. A short to voltage. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
7. Check for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the ICM. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S13430697522003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. With a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. The following conditions may cause this DTC to set: Low resistance in both the No. 1 and No. 3 secondary ignition circuits High resistance in both the No. 4 and No. 2 secondary ignition circuits An intermittent Crank Signal.
2. An Intermittent crank signal will result in an interrupted cam signal and may set this DTC.
3. To locate an intermittent problem, use the scan tool to monitor CMP Active Counter while running the engine. The counter should continuously count up to 255, then reset to zero. The counter will stop counting if a fault occurs in the cam signal circuit. If this DTC is determined to be intermittent, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The engine is running.

The PCM detects more than 30 CMP Resync counts in a 256-second window when Manifold Absolute Pressure (MAP) is more than 55 kPa.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Connect scan tool. Turn ignition switch to RUN position, engine off. If any other DTCs are set, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no other DTCs are set, go to next step.
3. Start the engine. Allow the engine to idle. Observe the CMP Resync Counter using the scan tool. Is the CMP Resync Counter incrementing? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S35953981162003040400000) .
4. Turn ignition switch to OFF position. Disconnect Ignition Control Module (ICM) harness connector. Using the Connector Test Adaptor Kit (J 35616-A), or equivalent, jumper each wire from the ICM harness connector to the ICM, except the CMP circuit. Start and idle the engine. Observe the CMP RESYNC on the scan tool. Did the CMP Resync Counter stop incrementing? If yes, go to next step. If no, go to step 6 .
5. Turn ignition switch to OFF position. Check for an intermittent and for a poor connection at the ICM. Did you find and correct the condition? If yes, go to step 9 . If no, go to step 7 .
6. Disconnect the PCM harness connectors. Check for an intermittent and for a poor connection of the CMP signal circuit at the PCM harness connector. Did you find and correct the condition? If yes, go to step 9 . If no, go to step 8 .
7. Replace ICM. After repair, go to step 9 .
8. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
9. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S01679867512003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
10. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. An intermittent fault in the CKP circuits may cause the PCM to resync the cam and may set DTC P0341. If the PCM is resyncing the camshaft, the CMP RESYNC COUNTER on the Scan tool will increment with the engine running.
2. An intermittent short to voltage on the CMP can set this DTC. A direct short to voltage on the CMP signal circuit will set P0340, as there will be no change in the CMP signal input.
3. Electromagnetic Interference (EMI) may also set DTC P0341. Inspect the wiring harness for damage. If the harness appears to be okay, observe the CMP resync counter on the scan tool while moving connectors and wiring harnesses related to the CMP sensor. If the CMP resync counter still does not count, while observing the scan tool, operate any non-engine related electrical components on the vehicle. A change in display will indicate the location of the malfunction.

If this DTC is determined to be intermittent, refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0204, P0300, P0301-P0304, P0336, P0340, P0341, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P0506, P0507, P0601, P0602, P1133, P1336 or P1441 are not set.
2. The engine has been running more than 530 seconds after the throttle has moved.
3. The BARO sensor parameter is more than 72 kPa.
4. The vehicle is in a closed loop operation.
5. The vehicle has been driven at more than 1000 RPM for more than 35 seconds if the vehicle has an automatic transmission.
6. The vehicle has been driven at more than 1000 RPM for more than 45 seconds if the vehicle has a manual transmission.
7. The battery voltage is more than 9 volts.

With vehicle stopped

1. The engine is idling less than 150 RPM from the desired idle.
2. The vehicle is in Drive (A/T) or in Neutral (M/T).
3. The TP sensor parameter is zero percent.
4. The ECT sensor parameter is greater than 156°F (69°C), and less than 257°F (125°C).
5. The IAT is greater than -4°F (-20°C), and less than 176°F (80°C).
6. The short term fuel trim is -28 to 28.
7. The catalytic temperature is greater than 950°F (510°C).
8. The above conditions are present for up to 30 seconds.

The PCM has determined the catalyst efficiency has degraded below a calibrated threshold.

1. The PCM illuminates the Malfunction Indicator Light (MIL) when the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Freeze Frame/Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to RUN position, engine off. Install scan tool. Were any component DTCs are set? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, go to next step.
3. Turn ignition switch to OFF position. Check the following conditions: Inspect the exhaust system for leaks. Inspect the rear Heated Oxygen Sensor (HO2S) 2 for leaks. Did you find a condition? If yes, go to next step. If no, go to step 5 .
4. Repair exhaust system as necessary. After repair, go to step 6 .
5. Replace TWC converter. After repair, go to next step.
6. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S11224207852003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
7. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

The catalyst test may abort due to a change in engine load. Do not change engine load, that is, do not reset A/C, coolant fan, or heater motor while a catalyst test is in progress.

Certain conditions may cause a catalytic converter to degrade. These conditions may include the following conditions

1. Engine misfire.
2. High engine oil or high coolant consumption.
3. Retarded spark timing.
4. Weak spark.
5. Lean fuel system.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0452 or P0453 are not set.
2. The ignition voltage is 10-18 volts.
3. The BARO sensor parameter is more than 75 kPa.
4. The Fuel Level sensor parameter is 15-85 percent.
5. The ECT sensor parameter is 39-86°F (4-30°C).
6. The IAT sensor parameter is 39-86°F (4-30°C).
7. The start-up ECT and IAT are within 16°F (9°C) of each other.
8. The Vehicle Speed Sensor (VSS) parameter is less than 75 MPH.

The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM will turn the Malfunction Indicator Light (MIL) OFF during the first consecutive trip in which the diagnostic has been run and passed.
2. A last test failed (current DTC) clears when the PCM turns OFF the MIL.
3. The history DTC will clear after the PCM runs and passes 40 consecutive warm up cycles with no failure.
4. The DTC can be cleared by using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Inspect the EVAP system for the following conditions: A loose, missing, or damaged service port Schrader valve. A loose, incorrect, missing, or damaged fuel fill cap. A damaged EVAP purge solenoid. Raise the vehicle on a hoist. Inspect the EVAP system for the following conditions: Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses. A damaged EVAP vent solenoid or EVAP canister. Did you find and correct the condition? If yes, go to step 34 . If no, go to next step.
3. Using a scan tool, clear the DTCs. Command the EVAP purge solenoid to 50 percent and back to zero percent using a scan tool. Do you hear or feel a clicking from the EVAP purge solenoid when it is commanded to 50 percent? If yes, go to next step. If no, go to step 5 .
4. Command the EVAP vent solenoid ON and OFF using the scan tool. Do you hear or feel a click as the EVAP vent solenoid is commanded ON and OFF? If yes, go to step 9 . If no, go to step 7 .
5. Disconnect the EVAP purge solenoid harness connector. Turn ignition switch to RUN position, engine OFF. Connect a test light between the ignition 1 voltage circuit of the EVAP purge solenoid and a known good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 25 .
6. Connect a test light between the ignition 1 voltage circuit of the EVAP purge solenoid and the control circuit of the EVAP purge solenoid. Command the EVAP purge solenoid to 50 percent and then to zero percent using a scan tool. Does the test light illuminate or pulsate when the EVAP purge solenoid is commanded to 50 percent and turn OFF when the EVAP purge solenoid is commanded to zero percent? If yes, go to step 20 . If no, go to step 18 .
7. Turn ignition switch to RUN position, engine OFF. Disconnect the EVAP vent solenoid harness connector. Connect a test light between the ignition 1 voltage circuit of the EVAP vent solenoid and a known good ground. Does the test light illuminate? If yes, go to next step. If no, go to step 26 .
8. Connect a test light between the ignition 1 voltage circuit of the EVAP vent solenoid and the control circuit of the EVAP vent solenoid. Command the EVAP vent solenoid ON, using a scan tool. Does the test light illuminate? If yes, go to step 21 . If no, go to step 19 .
9. Turn ignition switch to OFF position. Connect the Evaporative Emissions System Tester (EEST) (J 41413-200), or equivalent, power supply clips to a known good 12-volt source. Install the Fuel Tank Cap Adapter (J 41415-40), or equivalent, to the fuel fill pipe. Connect the fuel fill cap to the fuel tank cap adaptor. Connect the EEST nitrogen/smoke supply hose to the fuel tank cap adaptor. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Turn the nitrogen/smoke valve on the EEST control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the EVAP Service Port Vent Fitting (J 41413-VLV), or equivalent, to open the EVAP service port. Remove the J 41413-VLV once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke using the High Intensity White Light (J 41413-SPT), or equivalent. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step 34 . If no, go to next step.
10. Disconnect the fuel tank cap adaptor from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the EEST nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke using the high intensity White light. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step 34 . If no, go to next step.
11. Use the remote switch to stop introducing smoke. Install the fuel tank cap adaptor to the fuel fill pipe. Connect the EEST nitrogen/smoke supply hose to the fuel tank cap adaptor. Connect the vehicle fuel fill cap to the fuel tank cap adaptor. Command the EVAP vent solenoid open using a scan tool. Compare the Fuel Tank Pressure (FTP) sensor parameter using a scan tool, to the EEST pressure/vacuum gauge. Is the scan tool FTP sensor parameter within 1 in. H2O of the EEST pressure/vacuum gauge? If yes, go to next step. If no, go to step 22 .
12. Seal the EVAP system using the EVAP Purge/Seal function using a scan tool. Turn the nitrogen/smoke valve on the EEST control panel to NITROGEN. Use the EEST to pressurize the EVAP system to 10 in. H2O. Is the FTP sensor parameter more than 5 in. H2O? If yes, go to next step. If no, go to step 22 .
13. Use the remote switch to stop introducing nitrogen into the EVAP system. Increase the EVAP purge solenoid to 100 percent. Is the FTP sensor parameter Less than 1 in. H2O? If yes, go to step «DIAGNOSTIC AIDS»(ref-153397-S04086776432003040400000) . If no, go to next step.
14. Disconnect the EVAP purge vacuum source from the EVAP purge solenoid. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to step 24 . If no, go to next step.
15. Disconnect the EVAP purge pipe from the EVAP purge solenoid. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to step 29 . If no, go to step 17 .
16. Disconnect the EVAP purge pipe at the EVAP canister. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to 27 . If no, go to next step.
17. Disconnect the EVAP vapor pipe at the EVAP canister. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to step 31 . If no, go to step 29 .
18. Check the control circuit of the EVAP purge solenoid for an open or for a short to voltage. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 23 .
19. Check the control circuit of the EVAP vent solenoid for an open or for a short to voltage. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 23 .
20. Check for an intermittent and for a poor connection at the EVAP canister purge solenoid. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 29 .
21. Check for an intermittent and for a poor connection at the EVAP vent solenoid. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 30 .
22. Check for an intermittent and for a poor connection at the FTP sensor. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 32 .
23. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step 34 . If no, go to step 33 .
24. Repair the pinched or obstructed EVAP purge solenoid vacuum source. After repair, go to step 34 .
25. Repair the open or short to ground in the ignition 1 voltage circuit of the EVAP purge solenoid. Replace the fuse as necessary. After repair, go to step 34 .
26. Repair the open or short to ground in the ignition 1 voltage circuit of the EVAP vent solenoid. Replace the fuse as necessary. After repair, go to step 34 .
27. Repair restriction in the EVAP purge pipe. After repair, go to step 34 .
28. Repair the restriction in the EVAP vapor pipe. After repairs, go to step 34 .
29. Replace EVAP purge solenoid. After repairs, go to step 34 .
30. Replace the EVAP vent solenoid. After repairs, go to step 34 .
31. Replace EVAP canister. After repairs, go to step 34 .
32. Replace FTP sensor. After repairs, go to step 34 .
33. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
34. Connect the EEST to the fuel fill pipe. Turn the nitrogen/smoke valve to NITROGEN. Seal the EVAP system using the EVAP purge/seal function using a scan tool. Pressurize the EVAP system to the specified value. Observe the EEST pressure/vacuum gauge for 5 minutes. Does the EEST pressure/vacuum gauge remain constant? If yes, go to next step. If no, go to step 2 .
35. Using a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. To help locate intermittent leaks, use the Evaporative Emissions System Tester (EEST) (J 41413-200) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke using the High Intensity White Light (J 41413-SPT).
2. A temporary blockage in the EVAP purge solenoid, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
3. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles using the high intensity White light.
4. Reviewing the Failure 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.
5. For intermittent conditions, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0452 or P0453 are not set.
2. The ignition voltage is 10-18 volts.
3. The BARO sensor parameter is more than 75 kPa.
4. The fuel level sensor parameter is 15-85 percent.
5. The ECT sensor parameter is 39-86°F (4-30°C).
6. The IAT sensor parameter is 39-86°F (4-30°C).
7. The start up ECT and IAT are within 16°F (9°C) of each other.
8. The Vehicle Speed Sensor (VSS) is less than 75 MPH.

The EVAP system can achieve vacuum but a vacuum decay is detected during the diagnostic test.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Inspect EVAP system for the following conditions: A loose, missing, or damaged service port Schrader valve. A loose, incorrect, missing, or damaged fuel fill cap. A damaged EVAP canister purge solenoid. Raise vehicle on hoist. Inspect EVAP system for the following conditions: Any disconnected, improperly routed, kinked, or damaged EVAP pipes and hoses. A damaged EVAP canister vent solenoid or EVAP canister. Did you find and correct the condition? If yes, go to step 5 . If no, go to next step.
3. Turn ignition switch to OFF position. Connect the Evaporative Emissions System Tester (EEST) (J 41413-200), or equivalent, power supply clips to a known good 12-volt source. Install the Fuel Tank Cap Adapter (J 41415-40), or equivalent, to the fuel fill pipe. Connect the fuel fill cap to the fuel tank cap adapter. Connect the EEST nitrogen/smoke supply hose to the fuel tank cap adapter. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Turn the nitrogen/smoke valve on the EEST control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the EVAP Service Port Vent Fitting (J 41413-VLV), or equivalent, to open the EVAP service port. Remove the EVAP service port vent fitting once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke using the High Intensity White Light (J 41413-SPT), or equivalent. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to step 5 . If no, go to next step.
4. Disconnect the fuel tank cap adapter from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the EEST nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke using the high intensity light. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S37929723092003040400000) .
5. Turn the nitrogen/smoke valve to NITROGEN. Connect the nitrogen/smoke hose to the 0.20" (0.5 mm) test orifice on the bottom-front of the EEST. Use the remote switch to activate the EEST. Align the Red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the EEST. Install the fuel tank cap adapter to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the fuel tank cap adapter. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter's stable floating indicator position to the Red flag. Is the floating indicator below the Red flag? If yes, go to next step. If no, go to 2 .
6. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

To aid in locating intermittent leaks, use the EVAP Pressure/Purge Diagnostic Station (J 41413) to pressurize the EVAP system. Move all EVAP components while testing with the Ultrasonic Leak Detector (J 41416).

1. To help locate intermittent leaks, use the Evaporative Emissions System Tester (EEST) (J 41413-200), or equivalent, to introduce smoke into the EVAP system. Move all EVAP components while observing smoke using the High Intensity White Light (J 41413-SPT), or equivalent.
2. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles using the high intensity White light.
3. For intermittent conditions, go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0452 or P0453 are not set.
2. The ignition voltage is 10-18 volts.
3. The BARO sensor parameter is more than 75 kPa.
4. The Fuel Level sensor parameter is 15-85 percent.
5. The ECT sensor parameter is 39-86°F (4-30°C).
6. The IAT sensor parameter is 39-86°F (4-30°C).
7. The start-up ECT and IAT are within 16°F (9°C) of each other.
8. The VSS parameter is less than 75 MPH.

The FTP is less than -10 in. H2O for as long as 30 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Inspect the EVAP system for the following conditions: A damaged EVAP vent solenoid. A pinched EVAP vent hose. A damaged EVAP canister. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
3. Turn ignition switch to OFF position. Disconnect the EVAP purge line from the EVAP purge solenoid. Turn ignition switch to RUN position, engine OFF. Is the Fuel Tank Pressure (FTP) sensor parameter -1 to 1 in. H2O? If yes, go to next step. If no, go to step 10 .
4. Turn ignition switch to OFF position. Connect the EVAP purge pipe. Connect the Evaporative Emissions System Tester (EEST) (J 41413-200), or equivalent, power supply clips to a known good 12-volt source. Install the Fuel Fill Cap Adapter (J 41415-40) to the fuel fill pipe. Connect the fuel fill cap to the fuel fill cap adapter. Connect the EEST nitrogen/smoke supply hose to the fuel fill cap adapter. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Turn the nitrogen/smoke valve on the EEST control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to 5 in. H2O. Observe the FTP sensor parameter using a scan tool. Command the EVAP vent solenoid open. Is the FTP Sensor parameter less than 1 in. H2O? If yes, go to «DIAGNOSTIC AIDS»(ref-153397-S09135725402003040400000) . If no, go to next step.
5. Command the EVAP vent solenoid ON and OFF using a scan tool. Do you hear or feel the EVAP vent solenoid click when commanded ON and OFF? If yes, go to next step. If no, go to step 8 .
6. Disconnect the EVAP vent hose from the EVAP vent solenoid. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to step 12 . If no, go to next step.
7. Disconnect the EVAP vent hose from the EVAP canister. Is the FTP sensor parameter less than 1 in. H2O? If yes, go to step 14 . If no, go to step 13 .
8. Disconnect the EVAP vent solenoid. Probe the control circuit of the EVAP vent solenoid using a test light connected to battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step 12 .
9. Check the EVAP vent solenoid control circuit for a short to ground. Did you find and correct the condition? If yes, go to 17 . If no, go to step 15 .
10. Check for an intermittent and for a poor connection at the FTP sensor. Did you find and correct the condition? If yes, go to 17 . If no, go to step 15 .
11. Check for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to 17 . If no, go to step 16 .
12. Replace the EVAP vent solenoid. After repair, go to step 17 .
13. Replace the EVAP canister. After repair, go to step 17 .
14. Repair the pinched or restricted EVAP vent hose. After repair, go to step 17 .
15. Replace the FTP sensor. After repair, go to step 17 .
16. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
17. Turn ignition switch to RUN position. Connect all disconnected components. Connect the EEST to the fuel fill pipe. Turn ignition switch to RUN position, engine OFF. Command the EVAP vent solenoid closed using a scan tool. Turn the nitrogen/smoke valve on the EEST control panel to NITROGEN. Use the remote switch to pressurize the EVAP system to 5 in. H2O. Observe the FUEL TANK PRESSURE SENSOR parameter using a scan tool. Command the EVAP vent solenoid open using a scan tool. Is the FTP sensor parameter less than zero in. H2O? If yes, go to next step. If no, go to step 2 .
18. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. The EVAP system tests run when the engine is first started and meets the Conditions for Running the DTC. An intermittent condition could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP vent solenoid inlet or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.
2. Reviewing the Failure 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.
3. For intermittent conditions, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

The ignition switch is in RUN position.

The FTP voltage is less than 0.1 volt for more than 5 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The Malfunction Indicator Light (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
2. A history DTC will clear after 40 consecutive warm-up cycles without a fault.
3. Using scan tool, clear DTCs.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Using scan tool, observe FTP sensor voltage. Is FTP sensor voltage is less than 0.1 volt? If yes, go to step 4 . If no, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S07141864642003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to next step. If no, problem is intermittent. Go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to RUN position, engine off. Disconnect FTP sensor harness connector. Measure the voltage from 5-volt reference circuit of the FTP sensor using a Digital Multimeter (DMM). Does the DMM display 4.8-5.2 volts? If yes, go to step 6 . If no, go to next step.
5. Disconnect following components, while monitoring the DMM: MAP sensor. TP sensor. A/C pressure sensor. Does the DMM display 4.8-5.2 volts when any component is disconnected? If yes, go to step 11 . If no, go to step 7 .
6. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the FTP sensor and the signal circuit of the FTP sensor. Observe the FUEL TANK PRESSURE SENSOR parameter using a scan tool. Is fuel tank pressure sensor parameter 4.8-5.2? If yes, go to step 9 . If no, go to step 8 .
7. Check the 5-volt reference circuit of the FTP sensor for an open or short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
8. Check the signal circuit of the FTP sensor for an open or short to ground. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 10 .
9. Inspect for poor connections at the harness connector of the FTP sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
10. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
11. Replace component that affected the 5-volt reference circuit. After repairs, go to step 14 .
12. Replace FTP sensor. When complete, go to step 14 .
13. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
14. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S07141864642003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

The ignition switch is in RUN position.

The FTP sensor voltage is more than 4.9 volts for more than 5 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The Malfunction Indicator Light (MIL) will turn OFF after 3 consecutive ignition cycles in which the diagnostic runs without a fault.
2. A history DTC will clear after 40 consecutive warm-up cycles without a fault.
3. Using scan tool, clear DTCs.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Turn ignition switch to OFF position. Remove the fuel cap. Turn ignition switch to RUN position, engine off. Monitor the Fuel Tank Pressure (FTP) sensor voltage using the scan tool. Is the FTP sensor voltage greater than 4.3 volts? If yes, go to step 4 . If no, go to next step.
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME/FAILURE RECORDS data that you observed. Does the DTC fail this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Reinstall the fuel cap. Disconnect FTP sensor harness connector. Observe the FTP sensor voltage using the scan tool. Is the FTP sensor voltage less than 0.2 volt? If yes, go to next step. If no, go to step 7 .
5. Probe the ground circuit of the FTP sensor using a test light connected to battery voltage. Does the test light illuminate? If yes, go to next step. If no, go to step 8 .
6. Measure the voltage from the FTP sensor 5-volt reference circuit using a DMM. Is the voltage about 4.8-5.2 volts? If yes, go to step 10 . If no, go to step 11 .
7. Check the FTP sensor signal circuit for a short to voltage or a short to a 5-volt reference circuit. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
8. Check the ground circuit of the FTP sensor for an open. Did you find and correct the condition? If yes, go to step 14 . If no, go to next step.
9. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 13 .
10. Inspect for poor connections at the harness connector of the FTP sensor. Did you find and correct the condition? If yes, go to step 14 . If no, go to step 12 .
11. Repair 5-volt reference circuit for a short to voltage. After repairs, go to step 14 .
12. Replace FTP sensor. After repairs, go to step 14 .
13. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
14. Clear the DTCs using a scan tool. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S36264461502003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
15. Using a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1133 or P1441 are not set.
2. The ECT sensor parameter is more than 104°F (40°C).
3. The BARO sensor parameter sensor parameter is more than 72 kPa.
4. The engine run time is more than 20 seconds.
5. The Ignition 1 voltage is more than 11.0 volts.

1. The actual engine speed is 100 RPM less than the desired engine speed for 13 seconds.
2. The IAC position is more than 145 counts.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Set parking brake and block drive wheels. Install scan tool. Start the engine. Turn off all accessories. Use scan tool RPM control function to slowly increment engine speed to 1700 RPM, then to 600 RPM, then to 1700 RPM. Exit RPM control function. Does engine speed stabilized within 100 RPM? If yes, go to next step. If no, go to step 4 .
3. Observe FREEZE FRAME/FAILURE RECORDS data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within code enable criteria or as close to FREEZE FRAME/FAILURE RECORDS data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S11756285382003040400000) .
4. Turn ignition switch to OFF position. Disconnect IAC valve harness connector. Connect IAC Motor Driver (J 37027-A) to IAC valve. Start the engine. Use IAC motor driver to command IAC valve in until 600 RPM is reached. Use IAC motor driver to command IAC valve out until 1700 RPM is reached. Return engine speed to desired idle as indicated on scan tool data list. Did the engine speed parameter steadily decrease to near 600 RPM and steadily increase to near 1700 RPM when the IAC valve was commanded in and out? If yes, go to next step. If no, go to step 11 .
5. Connect a test light between one of the IAC valve control circuits and a good ground. Start the engine. Observe the IAC Counts parameter using a scan tool. Command high RPM with the IAC Motor Driver until the IAC Counts parameter starts to increment. Command low RPM with the IAC Motor Driver until the IAC Counts parameter starts to increment. Return the Engine Speed parameter to the Desired Idle Speed parameter. Repeat the above procedure for the other three IAC valve control circuits. Did the test light remain illuminated, never flashing, while the IAC Counts were incrementing for any of the IAC valve control circuits? If yes, go to next step. If no, go to step 11 .
6. Did the test light remain OFF, never flashing, while the IAC counts where incrementing at any of the IAC valve control circuits during the test? If yes, go to step 9 . If no, go to next step.
7. Connect a test light between the IAC coil "A" low circuit and the IAC coil "A" high circuit. Observe the IAC Counts parameter using a scan tool and observe the test light. Command high RPM using the IAC Motor Driver until the IAC Counts parameter starts to increment. Command low RPM using the IAC Motor Driver until the IAC Counts parameter starts to increment. Return the Engine Speed parameter to the Desired Idle Speed parameter. Repeat the above procedure using the test light connected between the IAC coil "B" low control circuit and the IAC coil "B" high control circuit. Did the test light stay illuminated and never flashing while the IAC Counts were incrementing for any of the IAC valve control circuits? If yes, go to next step. If no, go to step 16 .
8. Inspect for a poor connection at the IAC valve harness connector. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
9. Turn ignition switch to OFF position. Disconnect PCM harness connectors. Using a DMM, test the circuit where test light remained OFF for an open circuit, short to ground, or short to another IAC valve circuit. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
10. Turn ignition switch to RUN position, engine off. Using a DMM, test the circuit where the test light remained ON for the following: A short to voltage, or short to another IAC valve circuit. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
11. Visually/Physically inspect for the following: Throttle body damage and tampering. Throttle lever screw tampering (if equipped). Restricted air intake system. Inspect for a possible collapsed or clogged air intake duct before and after air filter element, restricted air filter element, or restriction at throttle body intake screen, if equipped. Remove IAC valve. Inspect for the following: A clogged IAC passage. Excessive deposits on throttle plate. Excessive deposits in throttle bore. Excessive deposits on IAC valve pintle. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 14 .
12. Inspect for a poor connection at the PCM harness connectors. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
13. Disconnect PCM harness connectors. Using a DMM, test all IAC valve circuits for high resistance. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
14. Inspect for a poor connection at the IAC valve harness connector. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
15. Replace IAC valve. When complete, go to step 17 .
16. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
17. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S42849937462003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
18. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

Inspect for the following conditions

1. A high resistance in an IAC circuit.
2. A restricted air intake system.
3. Proper operation and installation of all air intake components.
4. Any collapsed, clogged, or loose air intake ducts.
5. A clogged air filter.
6. Proper operation of the MAF sensor, if equipped.
7. A tampered with or damaged throttle stop screw.
8. A tampered with or damaged throttle plate, throttle shaft, or throttle linkage.
9. Any objects blocking the IAC passage or throttle bore.
10. Any excessive deposits in the IAC passage or on the IAC pintle.
11. Any excessive deposits in the throttle bore or on the throttle plate.
12. Any vacuum leaks.
13. A low or unstable idle condition could be caused by a non-IAC system problem that can not be overcome by the IAC valve.

If the problem is determined to be intermittent, go to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. DTCs P0105, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0502, P0503, P1133 or P1441 are not set.
2. The ECT sensor parameter is more than 104°F (40°C).
3. The BARO sensor parameter is more than 72 kPa.
4. The engine run time is more than 20 seconds.
5. The ignition voltage is more than 11.0 volts.

1. The actual engine speed is 200 RPM more than the desired engine speed for more than 12.5 seconds.
2. The IAC position is less than 2 counts.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Set parking brake and block drive wheels. Install scan tool. Start the engine. Turn off all accessories. Use scan tool RPM control function to slowly increment engine speed to 1700 RPM, then to 600 RPM, then to 1700 RPM. Exit RPM control function. Does the engine speed stabilize within 200 RPM of the commanded RPM during the test? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC, and within the parameters observed in the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to next step. If no, see «DIAGNOSTIC AIDS»(ref-153397-S37537873902003040400000) .
4. Turn ignition switch to OFF position. Disconnect IAC valve harness connector. Connect IAC Motor Driver (J 37027-A) to IAC valve. Start the engine. Use IAC motor driver to command IAC valve in until 600 RPM is reached. Use IAC motor driver to command IAC valve out until 1700 RPM is reached. Return engine to desired idle speed as indicated on scan tool data list. Did the engine speed steadily decrease to about 600 RPM and steadily increase to about 1700 RPM when the IAC valve was commanded in and out? If yes, go to next step. If no, go to step 11 .
5. Connect the test light between one of the IAC valve control circuits and a good ground. Start the engine. Observe the IAC Counts parameter using a scan tool and observe the test light. Command high RPM using the IAC Motor Driver until the IAC counts parameter starts to increment. Command low RPM using the IAC Motor Driver until the IAC Counts parameter starts to increment. Return the engine speed parameter to the desired idle speed parameter. Repeat the above procedure for the other three IAC valve control circuits. Did the test light remain ON, never flashing, while the IAC Counts were incrementing for any of the IAC valve control circuits? If yes, go to step 10 . If no, go to next step.
6. Did test light remained off (never flashing) while IAC counts were incrementing at any of IAC valve circuits during the test? If yes, go to step 9 . If no, go to next step.
7. Connect a test light between the IAC coil "A" low control circuit and the IAC coil "A" high control circuit. Observe the IAC counts parameter using a scan tool and observe the test light. Command high RPM using the AC Motor Driver until the IAC counts parameter starts to the increment. Command low RPM using the AC Motor Driver until the IAC Counts parameter starts to increment. Return the Engine Speed parameter to the Desired Idle Speed parameter as indicated on the scan tool data list. Repeat the above procedure using the test light connected between the IAC coil "B" low control circuit and the IAC coil "B" high control circuit. Did the test light stay illuminated and never flashing while the IAC Counts were incrementing for any of the IAC valve control circuits? If yes, go to next step. If no, go to step 16 .
8. Inspect for a poor connection at the IAC valve harness connector. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
9. Turn ignition switch to OFF position. Disconnect PCM harness connectors. Using a DMM, test the circuit where test light remained OFF for an open circuit, short to ground or short to another IAC valve circuit. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
10. Turn ignition switch to RUN position, engine off. Using a DMM, test the circuit where the test light remained ON for a short to voltage or short to another IAC valve circuit. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 12 .
11. Visually/Physically inspect for the following: Throttle body damage and tampering. Throttle lever screw tampering (if equipped). Vacuum leaks. Faulty, incorrectly installed PCV valve and hose (if equipped). Throttle shaft binding. Throttle linkage or cruise control linkage binding (if equipped). Remove IAC valve. Inspect for the following: Debris in the IAC passage. Excessive deposits on throttle plate. Excessive deposits in throttle bore. Excessive deposits on IAC valve pintle. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 14 .
12. Inspect for an intermittent and a poor connection at the PCM harness connectors. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
13. Disconnect PCM harness connectors. Check all IAC valve control circuits for high resistance. Did you find and correct the condition? If yes, go to step 17 . If no, go to step 16 .
14. Inspect for a poor connection at the IAC valve harness connector. Did you find and correct the condition? If yes, go to step 17 . If no, go to next step.
15. Replace IAC valve. When complete, go to step 17 .
16. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
17. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S34647444042003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
18. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

Inspect for the following conditions

1. A high resistance in an IAC circuit.
2. Correct PCV valve, properly installed and properly operating.
3. Proper operation and installation of all air intake components.
4. Proper installation and operation of MAF sensor, if equipped.
5. Tampered with or damaged throttle stop screw.
6. Tampered with or damaged throttle plate, throttle shaft, throttle linkage, or cruise control linkage, if equipped.
7. Skewed high TP sensor.
8. Excessive deposits in IAC passage or on IAC pintle.
9. Excessive deposits in throttle bore or on throttle plate.
10. Vacuum leaks.
11. High or unstable idle condition, could be caused by a non-IAC system problem that cannot be overcome by IAC valve.
12. If the problem is determined to be intermittent, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Is DTC P0602 set? If yes, go to next step. If no, go to step 5 .
3. Program PCM. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. Does DTC P0602 reset? If yes, go to next step. If no, go to step 6 .
4. Ensure all tool connections are secure. Ensure programming equipment is operating correctly. Ensure correct software/calibration package is used. Attempt to program PCM. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. Does DTC P0602 reset? If yes, go to next step. If no, go to step 6 .
5. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
6. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
7. Using a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay.

For complete details on programming the PCM, see POWERTRAIN CONTROL MODULE REPROGRAMMING under PROGRAMMING.

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0220, P0300-P0304, P0315, P0336, P0442, P0446, P0452, P0453, P0455, P0496, P0506, P0507, P0601, P0602 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The engine speed is 1000-3500 RPM.
4. The Ignition 1 signal parameter is more than 11 volts.
5. The Engine Run Time parameter is more than 200 seconds.
6. The engine is operating in closed loop.
7. The TP angle is 6-40 percent.
8. The EVAP control system is commanded open for more than 35 percent.
9. The purge learned memory is more than approximately 0.78.
10. The Fuel Level sensor parameter is more than 10 percent.
11. The MAP sensor parameter is 10-104 kPa.
12. The Air Flow Calculated parameter is more than 15 g/s.
13. The above conditions are met for 60 seconds.

The PCM detects that the HO2S 1 rich-to-lean counts or the lean-to-rich counts is less than a calibrated value.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate engine at normal operating temperature. Operate engine at greater than 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S 1 voltage is varying at greater than and less than 350-550 mV? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR SETTING DTC»(ref-153397-S15464789062003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, problem is intermittent. Go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 1 harness connector. Turn ignition switch to RUN position, engine off. Measure the voltage between the HO2S 1 high signal circuit on the PCM side to a good ground. Does the voltage measure 350-550 mV? If yes, go to next step. If no, go to step 9 .
5. Turn ignition switch to OFF position. Connect a 3-amp fused jumper wire between the HO2S 1 high signal circuit and HO2S 1 low signal circuit. Turn ignition switch to RUN position, engine off. Use a scan tool to monitor the HO2S 1 voltage for the sensor that applies to this DTC. Does scan tool indicate that HO2S 1 voltage is less than 20 mV? If yes, go to next step. If no, go to step 10 .
6. Turn ignition switch to OFF position. Remove the 3-amp fused jumper wire. Connect a test light between ignition 1 voltage circuit and a good ground. DO NOT use the HO2S 1 heater low control. Turn ignition switch to RUN position, engine off. Does test light illuminate? If yes, go to next step. If no, go to step 11 .
7. Connect a test light between ignition 1 voltage circuit and HO2S 1 heater low control circuit. Turn ignition switch to RUN position, engine off. Using a scan tool, command the HO2S 1 heater ON and OFF. Does the test light turn ON and OFF with each command? If yes, go to step 14 . If no, go to next step.
8. Does test light remain illuminated with each command? If yes, go to step 12 . If no, go to step 13 .
9. Check HO2S 1 high signal circuit for open, high resistance, short to ground or short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
10. Check HO2S 1 low signal circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
11. Check ignition 1 voltage circuit for an open, high resistance or short to ground. Replace ERLS fuse (Cavalier & Sunfire) or AUTO TRANS fuse (Alero & Grand Am) if necessary. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 15 .
12. Check HO2S 1 heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
13. Check HO2S 1 heater low control circuit for an open, high resistance or short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
14. Inspect for improper use of incorrect silicone RTV sealant, fuel contamination, exhaust leak, improperly installed HO2S or damaged wiring. Did you find and correct the condition? If yes, go to step 19 . If no, go to next step.
15. Inspect for poor connections at the harness connector of the HO2S 1. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 17 .
16. Inspect for poor connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
17. Replace HO2S 1. After repair, go to step 19 .
18. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
19. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within Conditions for Running DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S00269370982003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
20. Using a scan tool, observe the CAPTURE INFO. Does scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0220, P0300-P0304, P0315, P0336, P0442, P0446, P0452, P0453, P0455, P0496, P0506, P0507, P0601, P0602 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The engine speed is 1000-3500 RPM.
4. The Ignition 1 signal parameter is more than 11 volts.
5. The Engine Run Time parameter is more than 200 seconds.
6. The engine is operating in closed loop.
7. The TP angle is 6-40 percent.
8. The EVAP control system is commanded open for more than 35 percent.
9. The MAP sensor parameter is between 10-104 kPa.
10. The purge learned memory is more than approximately 0.78.
11. The Fuel Level sensor parameter is more than 10 percent.
12. The Air Flow Calculated parameter is more than 15 g/s.
13. The above conditions are met for 60 seconds.

The PCM detects that the difference between the HO2S 1 rich-to-lean average transition time and the lean-to-rich transition time is more than a calibrated value.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine over 1200 RPM for 2 minutes. Using a scan tool, observe the HO2S 1 voltage parameter. Does the scan tool indicate that the HO2S 1 voltage is varying above and below 350-650 mV? If yes, go to next step. If no, go to step 4 .
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, problem is intermittent. Go to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect the HO2S 1 harness connector. Turn ignition switch to RUN position, engine OFF. Using a DMM, measure the voltage of the HO2S 1 high signal circuit on the PCM side to a good ground. Does the voltage measure 350-550 mV? If yes, go to next step. If no, go to step 9 .
5. Turn ignition switch to OFF position. Connect a 3-amp fused jumper wire between the HO2S 1 high signal circuit and the HO2S 1 low signal circuit. Turn ignition switch to RUN position, engine off. Using a scan tool, monitor the HO2S 1 voltage for the sensor that applies to this DTC. Does the scan tool indicate that the HO2S 1 voltage is less than 20 mV? If yes, go to next step. If no, go to step 10 .
6. Turn ignition switch to OFF position. Remove the 3-amp fused jumper wire. Connect a test light between the ignition 1 voltage circuit and a good ground. Do not use the HO2S 1 heater low control. Turn ignition switch to RUN position, engine OFF. Does the test light illuminate? If yes, go to next step. If no, go to step 11 .
7. Connect a test light between the ignition 1 voltage circuit and the HO2S 1 heater low control circuit. Turn ignition switch to RUN position, engine OFF. Using a scan tool, command the HO2S 1 heater ON and OFF. Does the test light turn ON and OFF with each command? If yes, go to step 14 . If no, go to next step.
8. Does the test light remain illuminated with each command? If yes, go to step 12 . If no, go to step 13 .
9. Check the HO2S 1 high signal circuit for the following conditions: Open circuit. High resistance. Short to ground. Short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
10. Check the HO2S 1 low signal circuit for an open, a high resistance, or a short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
11. Check the ignition 1 voltage circuit for an open, a high resistance, or a short to ground. Replace the ERLS fuse (Cavalier & Sunfire) or AUTO TRANS fuse (Alero & Grand AM), if necessary. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 13 .
12. Check the HO2S 1 heater low control circuit for a short to ground. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
13. Check the HO2S 1 heater low control circuit for an open, a high resistance, or a short to voltage. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 16 .
14. Inspect for the following conditions: The use of incorrect silicone RTV sealant. Fuel contamination. An exhaust leak. The HO2S is installed correctly. Damaged wiring. Did you find and correct the condition? If yes, go to step 19 . If no, go to next step.
15. Inspect for poor connections at the harness connector of the HO2S 1. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 17 .
16. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 19 . If no, go to step 18 .
17. Replace the HO2S 1. After repair, go to step 19 .
18. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
19. Using scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within Conditions for Running DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S32011743622003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
20. Using a scan tool, observe the CAPTURE INFO. Does scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0220, P0300-P0304, P0315, P0336, P0442, P0446, P0452, P0453, P0455, P0496, P0506, P0507, P0601, P0602 or P1621 are not set.
2. The ECT sensor parameter is more than 158°F (70°C).
3. The Power Enrichment parameter is active.
4. The Ignition 1 signal parameter is more than 11 volts.
5. The engine is in closed loop.
6. The Fuel Level sensor parameter is more than 10 percent.
7. Engine run time is more than 10 seconds.
8. The above conditions are met for 5 seconds.

The PCM detects that the HO2S 1 parameter is more than 700 mV and the HO2S 2 parameter is less than 399 mV for 9.5 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine above 1200 RPM for 2 minutes. Observe the HO2S 2 voltage parameter using the scan tool. Does the scan tool indicate that the HO2S 2 voltage is less than 399 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S13368759862003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? Does scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect the HO2S 2 sensor harness connector. Turn ignition switch to RUN position, engine OFF. Measure the voltage of the HO2S 2 high signal circuit on the PCM side using a DMM. Does the voltage measure within 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 2 high signal circuit for a short to ground or a short to the low signal circuit. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 2 may be detecting a lean exhaust condition. Check for one of the following conditions: HO2S connector water intrusion. An exhaust leak between the HO2S 2 and the engine. See «SYMPTOMS - ENGINE EXHAUST»(ref-153405-S28471761252003050500000) under SYMPTOMS in TROUBLE SHOOTING - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article. Vacuum leaks. Incorrect fuel pressure. See «FUEL SYSTEMS»(ref-153407-S03923578782003040400000) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Lean fuel injectors. See «FUEL SYSTEM DIAGNOSIS (GASOLINE)»(ref-153407-S03416773192003120300000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. An inaccurate MAF sensor. Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the HO2S 2 sensor harness connector. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the PCM harness connectors. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the HO2S 2. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using a scan tool, clear DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate vehicle within Conditions for Running DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S13368759862003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0201-P0204, P0220, P0300-P0304, P0315, P0336, P0442, P0446, P0452, P0453, P0455, P0496, P0506, P0507, P0601, P0602 or P1621 are not set.
2. The Deceleration Fuel Cut-Off (DFCO) mode is active.
3. The battery voltage is more than 10 volts.
4. The ECT sensor parameter is more than 158°F (70°C).
5. The Fuel Level sensor parameter is more than 10 percent.
6. The engine run time parameter is more than 10 seconds.
7. The above conditions must be present for 7 seconds.

The PCM detects that the HO2S 2 parameter is more than 648 mV for more than 10 seconds.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate engine at normal operating temperature and at greater than 1200 RPM for 2 minutes. Using scan tool, observe HO2S 2 voltage parameter. Does scan tool indicate that HO2S 2 voltage is more than 1042 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC or as close to the Freeze Frame/Failure Records data that you observed. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S28069557062003040400000) . Does the scan tool indicate that this DTC failed this ignition? If yes, go to next step. If no, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.
4. Turn ignition switch to OFF position. Disconnect HO2S 2 harness connector. Turn ignition switch to RUN position, engine off. Using a Digital Multimeter (DMM), measure the voltage of the HO2S high signal circuit on the PCM side. Does the voltage measure within 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 2 high signal circuit for short to ground. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 2 is detecting a rich condition or may be contaminated. Check for HO2S connector water intrusion, silicone contaminated HO2S 2, fuel contaminated engine oil, incorrect fuel pressure, leaking fuel pressure regulator or rich fuel injectors. Repair any of the conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 2. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace HO2S 2. When complete, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S28069557062003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. DTCs P0122, P0123, P0131, P0132, P0133 or P0134 are not set.
2. The ECT sensor parameter is more than 70°F (20°C).
3. Engine Run Time parameter is more than 20 seconds.
4. Engine is operating in a closed loop operation.
5. Power Enrichment (PE) parameter is active.

The PCM detects that the HO2S 1 parameter is less than 300 mV for 5 seconds.

1. The PCM stores the DTC information into memory when the diagnostic runs and fails.
2. The Malfunction Indicator Light (MIL) will not illuminate.
3. The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.
4. The Driver Information Center (DIC), if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Operate the engine at normal operating temperature. Operate the engine above 1200 RPM for 2 minutes. Observe the HO2S 1 voltage parameter using a scan tool. Does the scan tool indicate that the HO2S 1 voltage is less than 300 mV? If yes, go to step 4 . If no, go to next step.
3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S06214885692003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to next step. If no, go «DIAGNOSTIC AIDS»(ref-153397-S15319062772003040400000) .
4. Turn ignition switch to RUN position. Disconnect the HO2S sensor harness connector. Turn ignition switch to RUN position, engine OFF. Measure the voltage of the HO2S 1 high signal circuit on the PCM side using a DMM. Does the voltage measure 350-550 mV? If yes, go to step 6 . If no, go to next step.
5. Check the HO2S 1 high signal circuit for a short to ground or a short to the HO2S 1 low signal circuit. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 8 .
6. The HO2S 1 is detecting a lean condition or may be contaminated. Inspect for the following conditions: HO2S connector water intrusion. Silicone contaminated HO2S. An exhaust leak between the HO2S 1 and the engine. See «SYMPTOMS - ENGINE EXHAUST»(ref-153405-S28471761252003050500000) under SYMPTOMS in TROUBLE SHOOTING - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article. Vacuum leaks. Incorrect fuel pressure. See «FUEL SYSTEMS»(ref-153407-S03923578782003040400000) in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Lean fuel injectors. See «FUEL SYSTEM DIAGNOSIS (GASOLINE)»(ref-153407-S03416773192003120300000) under FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE article. Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the HO2S 1 sensor. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 9 .
8. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
9. Replace the HO2S 1. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Use the scan tool to clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S06214885692003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If no, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If yes, system is okay at this time.

1. A restricted fuel filter can supply adequate amounts of fuel at idle, but may not be able to supply enough fuel during heavy acceleration. Water or alcohol in the fuel may cause low HO2S 1 voltage during acceleration.
2. High resistance in the ignition coil control circuits may cause this condition.
3. MAP sensor. High resistance in the MAP sensor circuits may cause this condition.
4. Inspect for faulty or plugged fuel injectors.

1. DTCs P0336, P0340 or P0341 are not set.
2. The ECT sensor parameter is more than 185°F (85°C).

The crankshaft position system variation values are not stored in the PCM memory.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Perform crankshaft position system variation learn procedure. See «CKP SYSTEM VARIATION LEARN PROCEDURE»(ref-153397-S15830427602003041400000) under PROGRAMMING. Is action complete? If yes, go to next step. If no, go to «DIAGNOSTIC AIDS»(ref-153397-S36190612702003040400000) .
3. Using a scan tool, clear the DTCs. Turn ignition switch to OFF position. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S36099652502003040400000) . You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC run and pass? If yes, go to next step. If no, go to step 2 .
4. Using a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

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

The crankshaft position system variation learn procedure is also required when the following service procedures have been performed, regardless of whether DTC P1336 is set

1. Engine replacement.
2. PCM replacement.
3. A harmonic balancer replacement.
4. Crankshaft replacement.
5. CKP sensor replacement.
6. Any engine repairs which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship.

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

1. A damaged reluctor wheel.
2. Excessive crankshaft runout.
3. A damaged crankshaft.
4. Interference in the signal circuit of the CKP sensor.
5. A coolant temperature that is not within the Conditions for Running the DTC.
6. The ignition switch is in the RUN position until the battery is drained.
7. A PCM power disconnect with the ignition switch in RUN position may erase the stored value and set the DTC P1336.

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0122, P0123, P0125, P0440, P0442, P0446, P0452 or P0453 are not set.
2. The ignition voltage is 10-18 volts.
3. The BARO sensor parameter is more than 75 kPa.
4. The Fuel Level sensor parameter is 15-85 percent.
5. The ECT sensor parameter is 39-86°F (4-30°C).
6. The IAT sensor parameter is 39°-86°F (4-30°C).
7. The start-up ECT and IAT are within 16°F (9°C) of each other.
8. The VSS parameter is less than 75 MPH.

The PCM detects vacuum during a non-purge condition.

1. The PCM illuminates the Malfunction Indicator Light (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the operating conditions to the Freeze Frame and updates the Failure Records.

1. The PCM turns OFF the Malfunction Indicator Light (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and DTC using a scan tool.

1. Perform diagnostic system check - engine controls. See «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-153397-S21035650842003040400000) under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
2. Disconnect the purge pipe from the EVAP purge solenoid. Connect a hand held vacuum gauge to the EVAP purge solenoid purge port. Disconnect the EVAP purge solenoid harness connector. Monitor vacuum on the vacuum gauge. Start the engine and allow the engine to idle. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 8 . If no, go to next step.
3. Connect the EVAP purge solenoid harness connector. Monitor vacuum on the vacuum gauge. Increase the idle to 1200-1500 RPM. Does the vacuum gauge indicate an increase in vacuum? If yes, go to step 5 . If no, go to next step.
4. Turn ignition switch to OFF position. Remove and then install the fuel fill cap. Turn ignition switch to RUN position, engine OFF. Observe the Fuel Tank Pressure (FTP) sensor parameter using a scan tool. Is the FTP sensor parameter -0.5 to 0.5 in. H2O? If yes, go to «DIAGNOSTIC AIDS»(ref-153397-S28323439172003040400000) .
5. Check the EVAP purge solenoid control circuit for a short to ground. Did you find and correct the conditions? If yes, go to step 11 . If no, go to next step.
6. Check for an intermittent and for a poor connection at the EVAP purge solenoid. Did you find and correct the condition? If yes, go to step 11 . If no, go to next step.
7. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step 11 . If no, go to step 10 .
8. Replace the FTP sensor. After repair, go to step 11 .
9. Replace the EVAP purge solenoid. After repair, go to step 11 .
10. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See «POWERTRAIN CONTROL MODULE REPROGRAMMING»(ref-153397-S15572173502003040400000) under PROGRAMMING. After replacing PCM, go to next step.
11. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. See «CONDITIONS FOR RUNNING DTC»(ref-153397-S20560422542003040400000) . Did the DTC fail this ignition? If yes, go to step 2 . If no, go to next step.
12. Using a scan tool, observe the CAPTURE INFO. Does the scan tool display any DTCs that you have not diagnosed? If yes, see «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(ref-153397-S21975802792003040400000) . If no, system is okay at this time.

1. An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge valve or a temporary blockage in the EVAP purge solenoid.
2. For intermittent conditions, refer to «INTERMITTENTS»(ref-153405-S25155180942003040400000) in TROUBLE SHOOTING - NO CODES - 2.2L ALERO, CAVALIER, GRAND AM & SUNFIRE - GASOLINE article.