Engine Controls Self-Diagnostics - 2.2l & 2.4l Chevrolet Cavalier III

MODEL IDENTIFICATION

Vehicle model is identified by fourth character of Vehicle Identification Number (VIN). VIN is stamped on metal pad on top of left end of instrument panel, near windshield. See MODEL IDENTIFICATION table.

MODEL IDENTIFICATION

INTRODUCTION

Most engine control problems are the result of mechanical breakdowns, poor electrical connections or damaged vacuum hoses. Before considering the computer system as a possible cause of problems, perform basic diagnostic procedures in appropriate BASIC DIAGNOSTIC PROCEDURES article. Failure to do so may result in lost diagnostic time.

If no faults were found while performing basic diagnostic procedures, go to DIAGNOSTIC PROCEDURE under SELF-DIAGNOSTIC SYSTEM. If no fault codes are present and driveability problems exist, go to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). If only intermittent codes are present, see INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

DESCRIPTION

Note. Powertrain Control Module (PCM) may also be referred to as Vehicle Control Module (VCM) in some diagnostic text and illustrations. Terms may be used interchangeably.

PCM is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, PCM will store a Diagnostic Trouble Code (DTC) and, in most cases, illuminate the Malfunction Indicator Light (MIL) located on instrument cluster. Malfunctions are recorded as hard failures or intermittent failures.

There are 4 types of DTC categories

1. Type "A" Emissions related. Illuminates MIL the first time DTC sets.
2. Type "B" Emissions related. Illuminates MIL if fault is active for 2 consecutive driving cycles.
3. Type "C" Non-emissions related. Does not illuminate MIL, but will illuminate SERVICE light.
4. Type "D" Non-emissions related. Does not illuminate MIL or SERVICE light.

Hard Failures

Most hard failures cause MIL to illuminate and remain on until malfunction is repaired. If MIL illuminates and remains on (light may flash) during vehicle operation, cause of malfunction must be determined. See DIAGNOSTIC PROCEDURE .

If a sensor fails, PCM will use a substitute value in its calculations to continue engine operation. In this condition, vehicle is functional, but it will most likely display degraded driveability.

Intermittent Failures

Intermittent failures cause MIL to flicker or glow and turn off about 10 seconds after intermittent fault goes away. Corresponding DTC, however, will be retained in PCM memory. If related fault does not reoccur within 50 engine starts, DTC will be erased from PCM memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in appropriate TROUBLE SHOOTING - NO CODES article.

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 1 or Tech 2 scan tool. See scan tool operator's manual for additional information.

The following are Tech 1 or Tech 2 scan tool sub-menus in the DTC INFO and SPECIFIC DTC modes

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

DIAGNOSTIC PROCEDURE

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

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. On-Board Diagnostic (OBD) system check must be performed before using specific DTC testing procedure. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) .
2. If DTCs were displayed, determine whether codes are hard or intermittent. Hard codes will cause MIL to illuminate continuously while engine is running. See «HARD OR INTERMITTENT TROUBLE CODE DETERMINATION»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__hard-or-intermittent-trouble-code-determination) . For diagnosing hard codes, proceed to appropriate DTC test. See DIAGNOSTIC TESTS. For diagnosing intermittent codes, see appropriate TROUBLE SHOOTING - NO CODES article.
3. If no DTCs are present and a driveability problem exists, refer to SYMPTOMS in appropriate TROUBLE SHOOTING - NO CODES article. Doing so will help identify proper system or component to check in appropriate SYSTEM & COMPONENT TESTING article.
4. After necessary repairs are made, clear DTCs, verify vehicle will enter "closed loop" operation and ensure DTC does not reset.

RETRIEVING DIAGNOSTIC TROUBLE CODES

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

Scheme 1

ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

Note. Tech 1 or Tech 2 scan tool is required to perform OBD system check.

The OBD system check determines

1. If Malfunction Indicator Light (MIL) operates.
2. If PCM is operating and can recognize a fault.
3. If any DTCs are stored.

After performing procedures in PRELIMINARY INSPECTION & ADJUSTMENTS, BASIC FUEL SYSTEM CHECKS and BASIC IGNITION SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article, this is the starting point for utilizing the self-diagnostic system for determining computer-related problems. After performing necessary tests as described in the OBD system check, if no codes are indicated and driveability problems still exist, see appropriate TROUBLE SHOOTING - NO CODES article and SCAN TOOL USAGE .

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

1. Connect scan tool. Turn ignition on, with engine off. If scan tool powers up, go to next step. If scan tool does not power up, go to «DLC DIAGNOSIS OR NO SCAN TOOL DATA»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dlc-diagnosis-or-no-scan-tool) .
2. If scan tool displays PCM data, go to next step. If scan tool does not display PCM data, go to «DLC DIAGNOSIS OR NO SCAN TOOL DATA»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dlc-diagnosis-or-no-scan-tool) .
3. Using scan tool, check for DTCs. If any LAST TEST FAIL, HISTORY or MIL request DTCs are present, go to next step. If no DTCs are present, go to step 5 .
4. Using scan tool, record FREEZE FRAME and FAILURE RECORDS information. Identify DTCs. See «DIAGNOSTIC TROUBLE CODE DEFINITIONS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__diagnostic-trouble-code-definitions) . After identification, diagnose DTCs. See DIAGNOSTIC TESTS.
5. Observe MIL. If MIL is illuminated, go to next step. If MIL is not illuminated, go to «MIL INOPERATIVE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__mil-inoperative) .
6. Using scan tool, command MIL off. If MIL turns off, go to next step. If MIL does not turn off, go to «MIL ON STEADY»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__mil-on-steady) .
7. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then stalls, go to NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
8. Allow engine to idle. During engine warm-up, check ECT, TP, MAP, O2 sensors and IAC valve for proper operation. Compare actual scan tool data with typical scan tool data values. If values are within limits, see appropriate TROUBLE SHOOTING - NO CODES article. If values are not within limits, go to appropriate SYSTEM & COMPONENT TESTING article.

MIL INOPERATIVE

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. If MIL is illuminated, go to next step. If MIL is not illuminated, go to step 4 .
3. Check for poor connections at battery feed circuit and ignition positive voltage 2 circuit. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 22 . If circuits are okay, go to step 5 .
4. Attempt to start engine. If engine starts, go to step 6 . If engine does not start, go to step 7 .
5. Check for poor PCM ground connections at PCM and engine block. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 22 .
6. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using a test light connected to ground, probe MIL control circuit at PCM harness connector. See WIRING DIAGRAMS article. If MIL illuminates, go to step 8 . If MIL does not illuminate, go to step 9 .
7. Check ignition and battery feed fuses. If fuses are okay, go to step 10 . If fuses are open, go to step 11 .
8. Check for poor battery feed, ignition positive voltage 2 or MIL control circuit connections. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 22 . If circuits are okay, go to step 12 .
9. If test light illuminates, go to step 13 . If test light does not illuminate, go to step 14 .
10. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Using a test light connected to ground, probe ignition positive voltage 2 circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 15 . If test light does not illuminate, go to step 16 .
11. Check for short to ground in fuse circuit that was open. Repair as necessary and replace fuse. After repairs, go to step 22 .
12. Replace PCM. Perform PCM relearn procedures. After repairs, go to step 22 .
13. Repair short to voltage in MIL control circuit. After repairs, go to step 22 .
14. Check for open or poor connection in MIL control circuit. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 22 . If circuit is okay, go to step 17 .
15. Using a test light connected to ground, probe PCM battery positive feed circuit at PCM harness connector. See WIRING DIAGRAMS article. If test light illuminates, go to step 18 . If test light does not illuminate, go to step 19 .
16. Repair open in ignition positive voltage 2 circuit. After repairs, go to step 22 .
17. Check for open in battery positive or ignition positive voltage 2 circuits. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 22 . If circuits are okay, go to step 20 .
18. Check for poor connections at battery positive voltage or ignition positive voltage 2 circuit. Repair as necessary. After repairs, go to step 22 . If circuits are okay, go to step 21 .
19. Repair open in PCM battery positive voltage circuit. After repairs, go to step 22 .
20. Replace Instrument Panel Cluster (IPC). After IPC replacement, go to step 22 .
21. Check for poor PCM ground connections at PCM and engine block. Repair as necessary. After repairs, go to next step. If connections are okay, go to step 12 .
22. Start engine and allow it to reach normal operating temperature. Using scan tool, check for DTCs. If DTCs are present, diagnose DTCs. See DIAGNOSTIC TESTS. If DTCs are not present, system is okay.

MIL ON STEADY

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. If MIL illuminates, go to next step. If MIL does not illuminate, go to «MIL INOPERATIVE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__mil-inoperative) .
3. Connect scan tool. Using scan tool, command MIL on and off. If MIL turns on and off as commanded, go to step 8 . If MIL does not turn on and off as commanded, go to next step.
4. Turn ignition off. Disconnect PCM connectors. Turn ignition on. If MIL does not illuminate, go to step 7 . If MIL illuminates, go to next step.
5. Check for short to ground in MIL control circuit. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to next step.
6. Replace instrument cluster. After repairs, go to step 8 .
7. Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
8. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step 1 .
9. Allow engine to reach normal operating temperature. Using scan tool, check for DTCs. If DTCs are present, diagnose DTCs. See DIAGNOSTIC TESTS. If DTCs are not present, system is okay.

DLC DIAGNOSIS OR NO SCAN TOOL DATA

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. If MIL illuminates, go to next step. If MIL does not illuminate, go to «MIL INOPERATIVE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__mil-inoperative) .
3. Connect scan tool. If scan tool powers up, go to next step. If scan tool does not power up, go to step 6 .
4. Using scan tool, attempt to communicate with Body Control Module (BCM) and Electronic Brake Control Module (EBCM). If scan tool communicates with both control modules, go to step 11 . If scan tool does not communicate with both control modules, go to next step.
5. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using scan tool, attempt to communicate with BCM and EBCM. If scan tool communicates with both control modules, go to step 13 . If scan tool does not communicate with both control modules, go to step 12 .
6. Using a DVOM, measure voltage between ground and DLC battery feed circuit at DLC. See WIRING DIAGRAMS article. If voltage is about battery voltage, go to next step. If voltage is not as specified, go to step 8 .
7. Using a DVOM, measure voltage between battery positive and both DLC ground circuits at DLC. See WIRING DIAGRAMS article. If voltage is about battery voltage at both circuits, go to step 9 . If voltage is not as specified, go to step 10 .
8. Repair poor connection, open or short to ground in battery feed circuit. After repairs, go to step 17 .
9. Check for open battery feed fuse and poor connections at DLC. Repair as necessary. After repairs, go to step 17 . If no problem is found, go to step 14 .
10. Repair open or poor connections in DLC ground circuits. After repairs, go to step 17 .
11. Check class 2 serial data line for an open or poor connection between PCM and circuit splice. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 13 .
12. Check class 2 serial data line for an open, short to power, short to ground or poor connection between PCM and DLC. See WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step 17 . If circuit is okay, go to step 14 .
13. Turn ignition off. Replace PCM. Perform PCM relearn procedures. After repairs, go to step 16 .
14. Install scan tool on another vehicle equipped with class 2 serial data and check for proper operation. If scan tool operates properly, go to appropriate TROUBLE SHOOTING - NO CODES article. If scan tool does not operate properly, go to next step.
15. Scan tool is malfunctioning. Refer to scan tool manufacturer's instructions. After repairs, go to step 17 .
16. Ensure PCM and CKP relearn procedures were performed if PCM was replaced. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then stalls, go to step 2 .
17. Allow engine to reach normal operating temperature. Using scan tool, check for DTCs. If DTCs are present, diagnose DTCs. See DIAGNOSTIC TESTS. If DTCs are not present, system is okay.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

Note. Use of Tech 1 or Tech 2 scan tool is required to retrieve DTCs. Refer to user reference manual supplied with scan tool.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

HARD OR INTERMITTENT TROUBLE CODE DETERMINATION

During any diagnostic procedure, determine if DTC(s) are hard failure codes or intermittent failure codes. Diagnostic procedures will not always help analyze intermittent codes. To determine hard codes and intermittent codes

1. Enter diagnostic mode. Read and record all stored DTCs. Exit diagnostic mode and clear DTCs. See «CLEARING DIAGNOSTIC TROUBLE CODES»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__clearing-diagnostic-trouble-codes) .
2. Apply parking brake and place transmission in Neutral or Park. Block drive wheels and start engine. MIL should turn off. Allow engine to reach normal operating temperature and continue to run for 2 minutes and note MIL.
3. If MIL illuminates, enter diagnostic mode. Read and record DTCs. This will reveal hard failure codes. Oxygen sensor related DTCs may require a road test to reset hard failures after DTCs were cleared.
4. If MIL does not illuminate, all stored DTCs were intermittent failures.

Note. DTCs will be recorded at various operating times. Some DTCs require operation of that sensor or switch for 5 seconds; others require operation for 5 minutes or longer at normal operating temperature, vehicle speed and load. Therefore, some DTCs may not set in a service bay operational mode and may require road testing vehicle in order to duplicate conditions under which code will set.

CLEARING DIAGNOSTIC TROUBLE CODES

To clear DTCs from memory, use scan tool, following scan tool manufacturer's instructions. Codes may also be cleared by disconnecting power supply to PCM for at least 30 seconds.

PCM LOCATION

PCM is located behind right side of dash.

Diagnostic Aids

Diagnostic aids are additional tips used to help diagnose trouble codes when inspected circuit is okay. Diagnostic aids may help lead to a definitive solution to trouble code problem.

SPECIAL TOOLS (DIAGNOSTIC)

Note. For scan data values, refer to scan tool manufacturer owner's manual or compare values with a known-good component or vehicle.

Note. A scan tool connected to DLC is used to read DTCs and check voltages in system on serial data line. A scan tool is required to retrieve vehicle information.

Computerized engine control system is most easily diagnosed using scan tool; however, other tools may aid in diagnosing problems. These tools are a tachometer, test light, ohmmeter, digital voltmeter with a 10-megohm input impedance (minimum), vacuum pump, vacuum gauge, fuel injector test light, and jumper wires with appropriate terminal ends and length. A test light, rather than a voltmeter, must be used when indicated by a diagnostic test. In addition, special jumper harnesses or testers may be required by manufacturer to facilitate diagnosis.

SCAN TOOL USAGE

Note. Before connecting scan tool to vehicle, diagnostic system should be checked to determine if system is operating properly and if information received will be accurate. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . If vehicle does not pass OBD system check, information received may be invalid.

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. About 80 percent of driveability problems occur without setting DTCs. Sensors that are out of calibration will not set a DTC but will cause driveability problems.

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.

SUMMARY

If no hard fault codes are present, driveability symptoms exist or intermittent DTC(s) exist, proceed to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

DIAGNOSTIC TESTS

Note. Before clearing DTCs, perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . Record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared.

Note. If PCM is replaced, NEW PCM must be programmed using special manufacturer's equipment.

Note. For component locations and PCM connector terminal identification, see appropriate SYSTEM & COMPONENT TESTING article.

DTC P0105: MAP/TP SENSOR PERFORMANCE/RANGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Circuit Description

PCM supplies a 5-volt reference signal and a ground circuit to both the MAP sensor and TP sensor. MAP sensor returns a signal to PCM relative to intake manifold pressure, and TP sensor returns a signal to PCM relative to throttle plate opening.

PCM can determine if sensors are out of range by comparing sensor values to expected limits predetermined by PCM during all modes of operation. DTC P0105 will set if MAP sensor is out of an expected range as determined by engine calibration.

For duplication of DTC, ensure

1. DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0440, P0442, P0502, P0506, P0507 or P1441 is not set.
2. Ensure engine speed is greater than 600 RPM.
3. TCC is stable within one percent.
4. Engine speed is stable within 50 RPM.
5. IAC valve is stable within 5 counts.
6. TP sensor is stable within 2 percent.

Diagnostic Procedures

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other MAP, TP, A/C or fuel tank pressure sensor DTCs are set, go to applicable DTC test. If specified DTCs are not set, go to next step.
3. Inspect condition of MAP and TP sensors and harnesses. Repair as necessary. After repairs, go to step 28 . If no problems are found, go to next step.
4. Using scan tool, monitor TP sensor voltage with throttle fully closed. If voltage is less than 0.9 volt, go to next step. If voltage is not as specified, go to step 6 .
5. Using scan tool, select TP ANGLE parameter. Monitor scan tool display while slowly depressing accelerator pedal to the floor and releasing (repeat several times). If value displayed on scan tool smoothly increases to greater than 98 percent and decreases to less than one percent according to accelerator pedal movement, go to step 7 . If value on scan tool does not change as specified, go to step 19 .
6. Check throttle body incorrect air rate adjustment, and binding or damaged linkage. Repair as necessary. After repairs, go to step 28 . If no problem is found, go to step 19 .
7. Using scan tool, compare BARO reading with a known-good vehicle. BARO reading should be within 3 kPa of other vehicle. Ensure readings are within specification for the present altitude. If readings are as specified, go to next step. If readings are not as specified, go to step 11 .
8. Using scan tool, monitor MAP sensor value while starting engine. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 10 .
9. With engine running, snap throttle while monitoring MAP sensor display on scan tool. If MAP sensor value changes rapidly, go to step 28 . If MAP sensor value does not change rapidly, go to next step.
10. Turn engine off. Turn ignition on. Remove MAP sensor or vacuum hose (if applicable) from manifold port. Check for leaks or restrictions. Repair as necessary. After repairs, go to step 28 . If no problem is found, go to next step.
11. Turn ignition off. Disconnect MAP sensor harness connector. Turn ignition on. If MAP sensor value on scan tool is zero volts, go to next step. If MAP sensor value on scan tool is not zero volts, go to step 13 .
12. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at MAP sensor harness connector. If MAP sensor value on scan tool is 5.0 volts, go to step 14 . If MAP sensor value on scan tool is not 5.0 volts, go to step 15 .
13. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check MAP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
14. Using a test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 16 . If test light does not illuminate, go to step 18 .
15. Check MAP sensor 5-volt reference circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 28 . If connection is okay, go to step 27 .
16. Check for poor connections at MAP sensor. Repair as necessary. After repairs, go to step 28 . If connections are okay, go to next step.
17. Replace MAP sensor. After repairs, go to step 28 .
18. Check MAP sensor ground circuit for poor connections. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
19. Turn ignition off. Disconnect TP sensor harness connector. Turn ignition on. If TP sensor value on scan tool is zero volts, go to next step. If TP sensor value on scan tool is not zero volts, go to step 21 .
20. Using a fused jumper wire, jumper 5-volt reference circuit to signal circuit at TP sensor harness connector. If TP sensor value on scan tool is 5 volts, go to step 22 . If TP sensor value on scan tool is not 5 volts, go to step 23 .
21. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Check TP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 27 .
22. Using a test light connected to battery positive, probe ground circuit at TP sensor harness connector. If test light illuminates, go to step 24 . If test light does not illuminate, go to step 25 .
23. Check TP sensor 5-volt reference or signal circuit for poor connections. Repair as necessary. After repairs, go to step 28 . If circuits are okay, go to step 27 .
24. Check for poor connections at TP sensor. Repair as necessary. After repairs, go to step 28 . If connections are okay, go to next step.
25. Replace TP sensor. After repairs, go to step 28 .
26. Check TP sensor ground circuit for poor connection or high resistance at TP sensor harness connector. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to next step.
27. Replace PCM. Program replacement PCM using necessary equipment. After repairs, go to next step.
28. Using scan tool, clear DTCs. Start engine and allow it to reach normal operating temperature. Select DTC, SPECIFIC, and then enter DTC P0105. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
29. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. If no undiagnosed DTCs are displayed, system is okay.

Turn ignition on, with engine off. MAP sensor voltage signal should be 4.5-4.8 volts. Compare this reading with a known-good vehicle with same style MAP sensor. Voltage readings should be within .4 volt of each other.

Ensure TP sensor is not stuck and MAP sensor has a dedicated vacuum source free of restriction or leaks. Check connections at all related components. Slight resistance in circuits or connections can set DTC P0105.

Other engine conditions such as incorrect cam timing, restricted exhaust, worn piston rings, and low fuel pressure may result in excessively high or low MAP values, causing DTC P0105 to set.

DTC P0107: MAP SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Manifold Absolute Pressure (MAP) sensor. As manifold pressure changes, monitored MAP sensor signal voltage changes. MAP sensor signal voltage should be 1.0-1.5 volts at idle and 4.5-4.8 volts at Wide Open Throttle (WOT). If MAP value is less than 11.8 kPa for at least 6.25 seconds, DTC P0107 will set.

For duplication of DTC, ensure DTCs P0122 or P0123 are not set, engine speed is less than 1000 RPM, or greater than 1000 RPM with Throttle Position (TP) sensor angle greater than 15 percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start and run engine at idle. Using scan tool, observe MAP sensor voltage. If voltage is less than .25 volt, go to next step. If voltage is not less than .25 volt, go to step 4 .
3. Turn ignition off. Disconnect MAP sensor connector. Connect a fused jumper wire between MAP sensor signal circuit and 5-volt reference circuit terminals at MAP sensor harness connector. Turn ignition on. Observe scan tool. If voltage is greater than 4.7 volts, go to step 5 . If voltage is not greater than 4.7 volts, go to step 6 .
4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MAP sensor voltage is less than .25 volt, go to step 3 . If MAP sensor voltage is not less than .25 volt, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
5. Turn ignition off. Disconnect and inspect MAP sensor connector. If connections are faulty, go to step 8 . If connections are okay, go to step 11 .
6. Turn ignition off. Disconnect jumper wire from MAP sensor connector. Using a test light connected to battery positive, probe MAP sensor signal circuit terminal at MAP sensor harness connector. Turn ignition on, engine off. Observe scan tool. If MAP sensor voltage is greater than 4 volts, go to next step. If MAP sensor voltage is not greater than 4 volts, go to step 13 .
7. Check MAP sensor 5-volt reference circuit for an open or short to ground. If 5-volt reference circuit is faulty, go to step 10 . If 5-volt reference circuit is okay, go to step 12 .
8. Repair connector pins and/or wiring as necessary. After repairs, go to step 15 .
9. Replace MAP sensor. After repairs, go to step 15 .
10. Repair 5-volt reference circuit to MAP sensor. After repairs, go to step 15 .
11. Remove MAP sensor vacuum hose from intake manifold. Check manifold port and hose for restriction. Repair as necessary. After repairs, go to step 15 . If manifold port and hose are okay, go to step 9 .
12. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 15 .
13. Turn ignition off. Check MAP sensor signal circuit for an open or short to chassis or sensor ground. If circuit is open or shorted to ground, go to next step. If circuit is okay, go to step 12 .
14. Repair MAP sensor signal circuit. After repairs, go to next step.
15. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates that this DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC test ran and passed, go to step 2 .
16. Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Turn ignition on, with engine off. MAP sensor voltage signal should be 4.5-4.8 volts. Compare this reading with a known-good vehicle with same style MAP sensor. Voltage readings should be within .4 volt of each other. After repairs are completed, use scan tool and access FUEL TRIM RESET function. Reset long term fuel trim to 128.

DTC P0108: MAP SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Manifold Absolute Pressure (MAP) sensor. PCM monitors a signal circuit from MAP sensor. As manifold pressure changes, MAP sensor signal voltage changes. MAP sensor signal voltage should be 1.0-1.5 volts at idle and 4.5-4.8 volts at Wide Open Throttle (WOT). If MAP value is greater than 82 kPa for at least 1.25 seconds.

For duplication of DTC, ensure DTCs P0122 or P0123 are not set, engine is running, Throttle Position (TP) sensor angle is less than 12 percent, and Vehicle Speed Sensor (VSS) signal is less than one MPH.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start and operate engine at idle. Using scan tool, observe MAP sensor voltage. If voltage is 4 volts or greater, go to next step. If voltage is not as specified, go to step 4 .
3. Turn ignition off. Disconnect MAP sensor connector. Turn ignition on. Using scan tool, observe MAP sensor voltage. If voltage is one volt or less, go to step 5 . If voltage is not as specified, go to step 6 .
4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MAP sensor voltage is 4 volts or greater, go to step 3 . If MAP sensor voltage is not as specified, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
5. Using test light connected to battery positive, probe ground circuit at MAP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 11 .
6. Turn ignition off. Check MAP sensor signal circuit for a short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 12 .
7. Using DVOM, measure voltage between ground and 5-volt reference circuit at MAP sensor harness connector. If voltage is about 5 volts, go to next step. If voltage is not as specified, go to step 9 .
8. Check for plugged or leaking MAP sensor vacuum hose. Repair as necessary. After repairs, go to step 10 . If vacuum hose is okay, go to step 13 .
9. Turn ignition off. Check 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 12 .
10. Repair vacuum source. After repairs, go to step 14 .
11. Check for an open in MAP sensor ground circuit or poor connection at PCM. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
13. Check for poor ground circuit connection at MAP sensor. Repair as necessary. If connection is okay, replace MAP sensor. After repairs, go to next step.
14. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates that this DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC test ran and passed, go to step 2 .
15. Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

Turn ignition on, with engine off. MAP sensor voltage signal should be 4.5-4.8 volts. Compare this reading with a known-good vehicle with same style MAP sensor. Voltage readings should be within .4 volt of each other. Check 5-volt reference for short to battery voltage. After repairs are completed, use scan tool and access FUEL TRIM RESET function. Reset long term fuel trim to 128.

DTC P0112: IAT SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies and monitors a 5-volt reference signal and a ground circuit to Intake Air Temperature (IAT) sensor. When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When PCM senses a signal voltage lower (temperature higher) than the normal operating range of the sensor, DTC P0112 will set.

For duplication of DTC, ensure engine has been running for more than 6 minutes, vehicle speed is greater than 15 MPH, and IAT sensor signal voltage indicates IAT temperature is greater than 262°F (128°C).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe IAT sensor value. If IAT sensor value is greater than 262°F (128°C), go to step 4 . If IAT sensor value is not greater than 262°F (128°C), go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Turn ignition off for about 15 seconds. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 262°F (128°C), go to next step. If IAT value is not greater than 262°F (128°C), no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Disconnect IAT sensor connector. Note IAT sensor value displayed on scan tool. If IAT sensor value is less than -22°F (-30°C), go to next step. If IAT sensor value is not less than -22°F (-30°C), go to step 6 .
5. Replace IAT sensor. After repairs, go to step 10 .
6. Turn ignition off. Connect a test light between positive battery terminal and signal circuit terminal at IAT sensor harness connector. If test light illuminates, go to next. If test light does not illuminate, go to step 9 .
7. Turn ignition off. Disconnect PCM harness connector. Connect test light between battery positive terminal and signal circuit at IAT sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
8. Repair short to ground in IAT sensor signal circuit. After repairs, go to step 10 .
9. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
10. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates that this DTC test ran and passed, go to next step. If scan tool does not indicate that this DTC test ran and passed , go to step 2 .
11. Check if additional DTCs are set. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If sensor temperatures are not within a few degrees of each other, test IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0113: IAT SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies and monitors a 5-volt reference signal and a ground circuit to Intake Air Temperature (IAT) sensor. When intake air is cold, sensor resistance is high and when intake air is warm, sensor resistance low. When IAT sensor signal voltage indicates an intake air temperature less than -40°F (-40°C) for greater than 3 seconds, DTC P0113 will set.

For duplication of DTC, ensure engine has been running for more than 6 minutes, engine coolant temperature is greater than -40°F (-40°C), and vehicle speed is greater than 24 MPH.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe IAT sensor value. If IAT sensor value is less than -22°F (-30°C), go to step 4 . If IAT sensor value is not less than -22°F (-30°C), go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Note IAT sensor value displayed on scan tool. If IAT sensor value is less than -22°F (-30°C), go to next step. If IAT value is not less than -22°F (-30°C), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Turn ignition off. Disconnect IAT sensor connector. Connect a jumper wire between signal circuit and sensor ground circuit terminals at IAT sensor harness connector. Turn ignition on. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 266°F (130°C), go to step 6 . If IAT sensor value is not greater than 266°F (130°C), go to next step.
5. Connect a jumper wire between ground and signal circuit terminal at IAT sensor harness connector. Note IAT sensor value displayed on scan tool. If IAT sensor value is greater than 266°F (130°C), go to step 7 . If IAT sensor value is not greater than 266°F (130°C), go to step 8 .
6. Turn ignition off. Check for poor connection at IAT sensor. Repair as necessary. After repairs, go to step 12 . If connection is okay, go to step 10 .
7. Turn ignition off. Check for an open IAT sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
8. Turn ignition off. Check for an open or short to voltage in IAT sensor signal circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
9. Check for poor IAT sensor ground or a poor IAT sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuits are okay, go to step 11 .
10. Replace IAT sensor. After repairs, go to step 12 .
11. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0113. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed through wire insulation or broken wire inside insulation.

If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within a few degrees of each other, test IAT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0117: ECT SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies and monitors a 5-volt reference signal and a ground circuit to Engine Coolant Temperature (ECT) sensor. With engine cold, sensor resistance is high and when engine is warm, sensor resistance is low. When ECT sensor indicates engine coolant temperature is greater than 280°F (138°C) for more than 6 seconds, DTC P0117 will set. For duplication of DTC, ensure engine has been running for more than 2 minutes.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe ECT sensor value. If ECT sensor value is greater than 266°F (130°C), go to step 4 . If ECT sensor value is not greater than 266°F (130°C), go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe ECT sensor value. If ECT sensor value is greater than 266°F (130°C), go to next step. If ECT sensor value is not greater than 266°F (130°C), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Turn ignition off. Disconnect ECT sensor connector. Turn ignition on, with engine off. Observe ECT sensor value. If ECT sensor value is less than - 22°F (- 30°C), go to step 6 . If ECT sensor value is not less than - 22°F (- 30°C), go to next step.
5. Check for short to ground in ECT sensor signal circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to step 7 .
6. Replace ECT sensor. After repairs, go to step 8 .
7. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
8. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0117. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
9. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within a few degrees of each other, test ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0118: ECT SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies and monitors a 5-volt reference signal and a ground circuit to Engine Coolant Temperature (ECT) sensor. With engine cold, sensor resistance is high and when engine is warm, sensor resistance is low. When ECT sensor indicates engine coolant temperature less than -40°F (-40°C) for more than 6 seconds, DTC P0118 will set. For duplication of DTC, ensure engine has been running for more than one minute.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe ECT sensor value. If ECT sensor value is less than - 22°F (- 30°C), go to step 4 . If ECT sensor value is not less than - 22°F (- 30°C), go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe ECT sensor value. If ECT sensor value is less than - 22°F (- 30°C), go to next step. If ECT sensor value is not less than - 22°F (- 30°C), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Turn ignition off. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT sensor signal circuit and sensor ground circuit terminals at ECT sensor harness connector. Turn ignition on, with engine off. If ECT sensor value is greater than 266°F (130°C), go to step 6 . If ECT value is not greater than 266°F (130°C), go to next step.
5. Connect a jumper wire between ground and signal circuit terminal at ECT sensor harness connector. If ECT sensor value is greater than 266°F (130°C), go to step 7 . If ECT sensor value is not greater than 266°F (130°C), go to step 8 .
6. Turn ignition off. Disconnect and inspect ECT sensor connector. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 10 .
7. Turn ignition off. Check for open ECT sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
8. Turn ignition off. Check ECT sensor signal circuit for an open or short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
9. Check for poor ECT sensor ground or a poor ECT sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuits are okay, go to step 11 .
10. Replace ECT sensor. After repairs, go to step 12 .
11. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0118. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM.

If engine is allowed to sit overnight, ECT and IAT sensor values should be within a few degrees of each other. If temperatures are not within a few degrees of each other, test ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0122: TP SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor throttle angle. TP sensor signal voltage should be less than one volt at idle and greater than 4.5 volts at wide open throttle. DTC P0122 will set if TP sensor voltage is less than 0.1 volt for more than 6 seconds. For duplication of DTC, ensure engine is running.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe TP sensor voltage. If voltage is less than .2 volt, go to step 4 . If voltage is not less than .2 volt, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If TP sensor voltage is less than .2 volt, go to next step. If TP sensor voltage is not less than .2 volt, go to step 12 .
4. Turn ignition off. Disconnect TP sensor connector. Connect a jumper wire between signal circuit and 5-volt reference circuit terminals at TP sensor harness connector. Turn ignition on. Observe TP sensor voltage. If voltage is greater than 4 volts, go to step 10 . If voltage is not greater than 4 volts, go to next step.
5. Remove jumper wire. Connect a test light between battery positive and signal circuit terminal at TP sensor harness connector. If voltage is greater than 4 volts, go to next step. If voltage is not greater than 4 volts, go to step 8 .
6. Check 5-volt reference circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
7. Check 5-volt reference circuit terminal for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit terminal is okay, go to step 11 .
8. Check TP sensor signal circuit for an open or short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
9. Check for poor TP sensor signal circuit terminal connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
10. Replace TP sensor. After repairs, go to step 12 .
11. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0122. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation.

If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. PCM 5-volt reference circuits are internally connected within PCM. Also, using FREEZE FRAME data may aid in determining conditions when DTC was set.

DTC P0123: TP SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies a 5-volt reference signal and a ground circuit to Throttle Position (TP) sensor, and a signal circuit to monitor throttle angle. TP sensor signal voltage should be about .5 volt at idle and 4.5 volts or greater at wide open throttle.

DTC P0123 will set if TP sensor voltage is greater than 3.9 volts for 14 seconds with engine speed less than 1500 RPM, or if TP sensor voltage is greater than 4.8 volts with engine speed greater than 1500 RPM.

For duplication of DTC, ensure DTC P0107 or P0108 is not set, engine is running, MAP is less than 60 kPa, and engine speed is less than 1500 RPM, or MAP is greater than 60 kPa and engine speed is greater than 1500 RPM.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off (throttle closed). Using scan tool, observe TP sensor voltage. If TP sensor voltage is greater than 0.8 volt, go to step 4 . If voltage is not greater than 0.8 volt, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If TP sensor voltage is greater than 3.9 volts, go to next step. If TP sensor voltage is not greater than 3.9 volts, go to step 12 .
4. Turn ignition off. Disconnect TP sensor connector. Turn ignition on, with engine off. Observe TP sensor voltage. If voltage is less than 0.3 volt, go to next step. If voltage is not less than 0.3 volt, go to step 6 .
5. Connect a test light between battery positive and sensor ground circuit terminal at TP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
6. Turn ignition off. Check for short to voltage in TP sensor signal circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
7. Check for short to battery voltage in 5-volt reference circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
8. Disconnect and inspect TP sensor connector. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 10 .
9. Check for open in ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 11 .
10. Replace TP sensor. After repairs, go to step 12 .
11. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0123. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
13. If any other DTCs are set, diagnose affected DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. If other DTCs are set for components that share the same ground and/or 5-volt reference circuit, check for faulty connections or wiring. The PCM 5-volt reference circuits are internally connected within PCM. Also, using FREEZE FRAME data may aid in determining conditions when DTC was set.

DTC P0125: ECT EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL

Note. For circuit reference, See WIRING DIAGRAMS article.

The purpose of the engine cooling system is to maintain an efficient engine coolant temperature level during all engine operating conditions. The Engine Coolant Temperature (ECT) sensor monitors the temperature of the engine coolant. The PCM uses the ECT sensor input for engine control and enabling criteria for some diagnostics.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0420, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503, P0506 or P1441 are not set.
2. Engine running for greater than 30 seconds, but less than 20 minutes.
3. ECT is greater than 95°F (35°C).
4. Minimum IAT is greater than 95°F (35°C).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check if any DTCs are set. If any DTCs are set, diagnose affected DTC(s). If no other DTCs are set, go to next step.
3. Using scan tool, check engine coolant temperature. If coolant temperature is 165°F (73°C) or greater, go to next step. If coolant temperature is not 165°F (73°C) or greater, go to step 5 .
4. Check thermostat for proper operation. If thermostat is okay or after replacing thermostat, go to next step.
5. Cool engine to ambient temperature. Turn ignition on, with engine off. Using scan tool, compare ECT and IAT sensor readings. If readings are close to each other, go to step 7 . If readings are not close to each other, go to next step.
6. Turn ignition off. Disconnect ECT sensor harness connector. Using a DVOM, check resistance between ECT sensor terminals. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT resistance value is as specified, go to next step. If ECT resistance value is not as specified, go to step 12
7. Turn ignition on, with engine off. Using scan tool, check ECT sensor value. If scan tool reading is less than - 22°F (- 30°C), go to next step. If scan tool reading is not - 22°F (- 30°C), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Using a jumper wire, connect jumper wire between ECT sensor harness connector terminals. If ECT sensor value is greater than 266°F (130°C), go to next step. If scan tool value is not greater than 266°F (130°C), go to step 10 .
9. Check coolant level and thermostat operation. Repair as necessary. After repairs, go to step 13 . If no problems were found, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
10. Turn ignition off. Check for poor connections at ECT sensor and PCM. Repair as necessary. After repairs, go to step 13 . If connectors are okay, go to next step.
11. If PCM connectors are okay, replace PCM. Program replacement using required equipment. Perform CKP SYSTEM VARIATION LEARN PROCEDURE. See «DTC P1336: CKP SYSTEM VARIATION NOT LEARNED»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p1336-ckp-system-variation-not) . After repairs, go to step 13 .
12. Turn ignition off. Replace ECT sensor. After replacing sensor, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0125. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Check and repair wiring as necessary. If wiring is okay, connect a DVOM between signal circuit terminal at ECT sensor harness connector and ground circuit terminal at PCM harness connector. Observe DVOM and bend, wiggle and twist related connectors and wiring harness. If a fault is induced, resistance reading will change.

Check for a skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0128: ECT LESS THAN THERMOSTAT REGULATING TEMPERATURE (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The purpose of the engine cooling system is to maintain an efficient engine coolant temperature level during all engine operating conditions. The Engine Coolant Temperature (ECT) sensor monitors the temperature of the engine coolant. The PCM uses the ECT sensor input for engine control and enabling criteria for some diagnostics.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0420, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503, P0506 or P1441 are not set.
2. Engine running for greater than 30 seconds, but less than 20 minutes.
3. ECT is less than 149°F (65°C).
4. Minimum IAT is greater than 27°F (- 7°C).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check if any DTCs are set. If any DTCs are set, diagnose affected DTC(s). If no other DTCs are set, go to next step.
3. Using scan tool, check engine coolant temperature. If coolant temperature is 165°F (73°C) or greater, go to next step. If coolant temperature is not 165°F (73°C) or greater, go to step 5 .
4. Check thermostat for proper operation. If thermostat is okay or after replacing thermostat, go to next step.
5. Cool engine to ambient temperature. Turn ignition on, with engine off. Using scan tool, compare ECT and IAT sensor readings. If readings are close to each other, go to step 7 . If readings are not close to each other, go to next step.
6. Turn ignition off. Disconnect ECT sensor harness connector. Using a DVOM, check resistance between ECT sensor terminals. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT resistance value is as specified, go to next step. If ECT resistance value is not as specified, go to step 12
7. Turn ignition on, with engine off. Using scan tool, check ECT sensor value. If scan tool reading is less than - 22°F (- 30°C), go to next step. If scan tool reading is not - 22°F (- 30°C), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Using a jumper wire, connect jumper wire between ECT sensor harness connector terminals. If ECT sensor value is greater than 266°F (130°C), go to next step. If scan tool value is not greater than 266°F (130°C), go to step 10 .
9. Check coolant level and thermostat operation. Repair as necessary. After repairs, go to step 13 . If no problems were found, see .
10. Turn ignition off. Check for poor connections at ECT sensor and PCM. Repair as necessary. After repairs, go to step 13 . If connectors are okay, go to next step.
11. If PCM connectors are okay, replace PCM. Program replacement using required equipment. Perform CKP SYSTEM VARIATION LEARN PROCEDURE. See «DTC P1336: CKP SYSTEM VARIATION NOT LEARNED»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p1336-ckp-system-variation-not) . After repairs, go to step 13 .
12. Turn ignition off. Replace ECT sensor. After replacing sensor, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0125. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Check and repair wiring as necessary. If wiring is okay, connect a DVOM between signal circuit terminal at ECT sensor harness connector and ground circuit terminal at PCM harness connector. Observe DVOM and bend, wiggle and twist related connectors and wiring harness. If a fault is induced, resistance reading will change.

Check for a skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0128: ECT LESS THAN THERMOSTAT REGULATING TEMPERATURE (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

The purpose of the engine cooling system is to maintain an efficient engine coolant temperature level during all engine operating conditions. The Engine Coolant Temperature (ECT) sensor monitors the temperature of the engine coolant. The PCM uses the ECT sensor input for engine control and enabling criteria for some diagnostics.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0130, P0131, P0132, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0420, P0440, P0442, P0446, P0452, P0453, P0480, P0502, P0503, P0506 or P1441 are not set.
2. Engine running for greater than 30 seconds, but less than 20 minutes.
3. ECT is less than 149°F (65°C).
4. Minimum IAT is greater than 27°F (-7°C).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check if this DTC was set during this ignition cycle. If this DTC was set in this ignition cycle, go to step 4 . If this DTC was not set during this ignition cycle, go to next step.
3. Cool engine until IAT value is within 10°F (6°C) of ECT. Operate vehicle within the conditions for setting this DTC. Check if DTC P0128 resets. If this DTC resets, go to next step. If this DTC does not reset, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Using scan tool, observe ECT reading. Turn ignition off. Disconnect ECT sensor harness connector. Using a DVOM, check resistance between ECT sensor terminals. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT resistance value is not as specified, go to next step. If ECT resistance value is as specified, diagnose thermostat or vehicle cooling system.
5. Replace ECT sensor. After replacing ECT sensor, go to next step.
6. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, system is okay. If scan tool does not indicate this test ran and passed, repeat step 2 .

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Check and repair wiring as necessary. If wiring is okay, connect a DVOM between signal circuit terminal at ECT sensor harness connector and ground circuit terminal at PCM harness connector. Observe DVOM and bend, wiggle and twist related connectors and wiring harness. If a fault is induced, resistance reading will change.

Check for a skewed ECT sensor. See appropriate SENSOR OPERATING RANGE CHARTS article.

DTC P0130: O2S 1 CIRCUIT CLOSED-LOOP PERFORMANCE (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

When engine is first started, engine operates in open-loop operation, ignoring O2S signal and calculating air/fuel ratio based on inputs from the ECT, TP and MAP sensors only. PCM will begin using O2S signal for controlling fuel delivery (closed-loop) when O2S has a varying voltage output showing that it is hot enough to operate properly and ECT has increased a minimum amount based on ECT at engine start-up.

For duplication of DTC, ensure

1. DTCs P0107, P0108, P0117, P0118, P0122, P0123, P0131, P0132, P0134, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0325, P0336, P0440, P0442, P0446, P0502, P0601, P0602, P1441 or P1621 are not set.
2. Engine running for greater than 65 seconds.
3. Engine speed at 1200-3400 RPM.
4. TP sensor angle is 10-40 percent.
5. ECT greater than 149°F (65°C).
6. Above conditions have been met for 2 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for DTCs. If any other DTCs are set, diagnose affected DTC(s) first. Start and operate engine at 1200 RPM or greater for 2 minutes. Using scan tool, observe HO2S voltage parameter. Voltage reading should be varying within a range of 400-500 mV. If voltage reading is varying outside of specified value, go to next step. If voltage reading is varying within the specified value, go to step 4
3. Operate vehicle within the Fail Safe Records conditions. If scan tool indicates that this DTC failed in this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Check for exhaust leaks, improperly installed HO2S or damaged sensor wiring. Repair as necessary. After repairs, go to step 13 . If no problems were found, go to next step.
5. Turn ignition off. Disconnect oxygen sensor harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between chassis ground and HO2S signal circuit at harness connector. If voltage reading is about 450 mV, go to next step. If voltage reading is not about 450 mV, go to step 8
6. Connect a jumper wire between HO2S harness connector terminals. Using scan tool, monitor HO2S voltage. If voltage reading is about zero millivolt, go to step 9 . If voltage reading is not about zero millivolt, go to next step.
7. Check HO2S low circuit for open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
8. Check HO2S signal circuit for open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
9. Check for poor connections at HO2S connectors. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
10. Check for alcohol contaminated fuel or improper use of RTV sealant, affecting HO2S. Repair cause of contamination and replace HO2S. After repairs, go to step 13 .
11. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Setting of this DTC or slow O2S response is most likely caused by high fuel pressure, leaking injector, faulty MAP sensor, faulty fuel pressure regulator or O2S contamination.

DTC P0131: O2S 1 CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies about .45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 varies voltage from about one volt when exhaust is rich to about .10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage is less than predetermined voltage, DTC P0131 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602, or P1441 are not set.
2. Airflow is greater than 3 gm/s.
3. ECT is greater than 158°F (70°C).
4. System is in closed-loop operation.
5. TP sensor angle is 5-50 percent.
6. Engine has met above conditions for 20 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start engine and allow it to reach normal operating temperature. Using scan tool, observe O2S 1 voltage. If voltage remains less than 44 mV (440 mV on 2.4L), go to step 4 . If voltage does not remain less than 44 mV (440 mV on 2.4L), go to next step.
3. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe O2S 1 voltage. If voltage remains less than 44 mV (440 mV on 2.4L), go to next step. If voltage does not remain less than 44 mV (440 mV on 2.4L), go to step 7 .
4. Turn ignition off. Disconnect O2S 1 connector. Turn ignition on, engine off. Observe O2S 1 voltage. If voltage is 407-509 mV (less than 400 mV on 2.4L), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If voltage is not 407-509 mV (less than 400 mV on 2.4L), go to next step.
5. Check for short to ground in O2S 1 signal circuit. Repair as necessary. After repairs, go to step 7 . If circuit is okay, go to next step.
6. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
7. Reconnect O2S 1 connector. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0131. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
8. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

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

DTC P0132: O2S 1 CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies about .45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 varies voltage from about one volt when exhaust is rich to about .10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage is less than predetermined voltage, DTC P0132 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 3 gm/s.
3. ECT is greater than 158°F (70°C).
4. Engine is operating in closed loop.
5. TP sensor angle is 5-50 percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Ensure engine is at normal operating temperature. Using scan tool, observe O2S 1 sensor voltage. If voltage remains greater than 1042 mV (greater than 600 mV on 2.4L engines), go to step 4 . If voltage does not remain greater than 1042 mV (greater than 600 mV on 2.4L engines), go to next step.
3. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Observe O2S 1 sensor voltage. If voltage remains greater than 1042 mV (greater than 110 mV on 2.4L engines), go to next step. If voltage does not remain greater than 1042 mV (greater than 110 mV on 2.4L engines), go to step 7 .
4. Turn ignition on, with engine off. Disconnect O2S 1 connector. Measure voltage between ground and O2S 1 harness connector. Observe O2S 1 voltage. If voltage is 500-600 mV, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If voltage is not 500-600 mV, go to next step.
5. Check for short to ground in O2S 1 signal circuit. Repair as necessary. After repairs, go to step 7 . If wiring is okay, go to next step.
6. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
7. Reconnect O2S 1 harness connector. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
8. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check if fuel pressure is too high. PCM can compensate for some increase, however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP system for fuel saturation. Disconnect MAP sensor harness connector and see if rich condition is corrected. If rich condition is corrected, check for faulty MAP sensor. Check for oxygen sensor silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P0133: O2S 1 CIRCUIT - SLOW RESPONSE (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times O2S 1 switches from rich to lean and from lean to rich. PCM then adds amount of time O2S 1 took to complete all switches. With this information, an average time for all switches can be determined. Whenever average time to switch is too slow, DTC P0133 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. ECT is greater than 167°F (75°C).
3. Engine speed is 1800-2300 RPM.
4. Engine is operating in closed loop.
5. TP sensor angle is 8-15 percent.
6. Evaporative emission control system is commanded open for greater than 80 percent.
7. Purge learned memory is greater than about 0.86.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTCs. If no other DTCs are present, go to next step.
3. Start engine. Ensure engine is at normal operating temperature. Operate vehicle within the conditions required for setting this DTC. Using scan tool, monitor O2S 1 for the following: LEAN/RICH AVG. (ms). RICH/LEAN AVG. (ms). RICH/LEAN-to-LEAN/RICH RATIO (greater than, less than). If AVG. values are less than 249 ms, or RATIO is greater than 0.2 or less than 6.0, go to next step. If readings are not as specified, go to step 17 .
4. Turn ignition off. Check O2S 1 for proper installation. Check condition of O2S 1 circuits and connections. If a problem is found, go to step 9 . If no problems are found, go to next step.
5. Check exhaust manifold for leaks. Repair as necessary. After repairs, go to step 3 . If no leaks are found, go to next step.
6. Disconnect O2S 1 connector. Turn ignition on. Using scan tool, monitor O2S 1 voltage. If voltage is 407-509 mV, go to next step. If voltage is not 407-509 mV, go to step 10 .
7. Connect a jumper wire between ground and signal circuit terminal at O2S 1 harness connector (PCM side). If voltage is less than 200 mV, go to next step. If voltage is 200 mV or greater, go to step 11 .
8. Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After repairs, go to step 17 .
9. Repair condition as necessary. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is found, replace oxygen sensor. After repairs, go to step 17 .
10. Repair short to ground in O2S 1 signal circuit. After repairs, go to step 17 .
11. Remove jumper wire. Measure voltage between ground and signal circuit at O2S 1 harness connector. If voltage is greater than 407 mV, go to next step. If voltage is not greater than 407 mV, go to step 13 .
12. Turn ignition off. Reconnect O2S 1 connector. Disconnect PCM harness connectors. Measure resistance between ground and O2S 1 ground circuit terminal at PCM harness connector. If resistance is less than 5 ohms, go to step 14 . If resistance is not less than 5 ohms, repair open in ground circuit. After repairs, go to step 17 .
13. Turn ignition off. Disconnect PCM harness connectors. Measure resistance of signal circuit between O2S 1 harness connector and PCM harness connector. If resistance is less than 5 ohms, go to step 15 . If resistance is not less than 5 ohms, repair open in sensor signal circuit. After repairs, go to step 17 .
14. Check O2S 1 low signal circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 17 . If low signal circuit terminal is okay, go to step 16 .
15. Check O2S 1 signal circuit terminal connection at PCM harness connector. Repair as necessary. After repairs, go to step 17 . If signal circuit terminal is okay, go to next step.
16. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
17. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0133. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
18. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check if fuel pressure is too high. PCM can compensate for some increase; however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP system for fuel saturation. Disconnect MAP sensor harness connector and see if rich condition is corrected. If rich condition is corrected, check for faulty MAP sensor. Check for oxygen sensor silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P0133: O2S 1 CIRCUIT - SLOW RESPONSE (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times O2S 1 switches from rich to lean and from lean to rich. PCM then adds amount of time O2S 1 took to complete all switches. With this information, an average time for all switches can be determined. Whenever average time to switch is too slow, this DTC will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. ECT is greater than 167°F (75°C).
3. Engine speed is 1800-2300 RPM.
4. Engine is operating in closed-loop.
5. TP sensor angle is 8-15 percent.
6. Evaporative emission control system is commanded open for greater than 80 percent.
7. Purge learned memory is greater than about 0.86.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTCs before proceeding with test. If no other DTCs are present, start engine and warm engine to normal operating temperature. Operate engine at greater than 1200 RPM for 2 minutes. Using scan tool, monitor HO2S voltage parameter. HO2S voltage should be varying within a range of 400-500 mV. If voltage is varying out of specified range, go to next step. If voltage is not varying out of range, go to step 4 .
3. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this DTC failed in this ignition cycle, go to next step. If scan tool does not indicates that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Check for exhaust leaks, improperly installed HO2S or faulty wiring. Repair as necessary. After repairs, go to step 13 . If no problems were found, go to next step.
5. Turn ignition off. Disconnect HO2S harness connector. Turn ignition on. Using a DVOM, check voltage between chassis ground and signal circuit at HO2S harness connector. If voltage reading is about 450 mV, go to next step. If voltage reading is not about 450 mV, go to step 8 .
6. Connect a jumper wire between ground and low circuit signal circuit at HO2S harness connector. If scan tool indicates HO2S voltage at about zero millivolts, go to step 9 . If scan tool does not indicate HO2S voltage at about zero millivolts, go to step 11 .
7. Check the low circuit for an open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
8. Check the signal circuit for an open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
9. Check for poor connections at HO2S connector. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
10. Check for alcohol contamination in fuel, improper use of RTV sealant or faulty HO2S. Repair as necessary, after repairs, go to step 13 .
11. Check for poor connections at PCM connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check if fuel pressure is too high. PCM can compensate for some increase; however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP system for fuel saturation. Disconnect MAP sensor harness connector and see if rich condition is corrected. If rich condition is corrected, check for faulty MAP sensor. Check for oxygen sensor silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P0134: O2S 1 CIRCUIT - INSUFFICIENT ACTIVITY (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies about .45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 supplies a varying voltage from about one volt when exhaust is rich to about .10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage remains at or about .45 volt for an extended period, DTC P0134 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 3 gm/s.
3. ECT is greater than 158°F (70°C).
4. TP sensor angle is 4-56 percent for 20 seconds.
5. Engine run time is greater than 30 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Ensure engine is at normal operating temperature. Start engine. Increase engine speed to 1200 RPM for 2 minutes. If scan tool indicates closed loop, go to next step. If scan tool does not indicate closed loop, go to step 4 .
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If scan tool indicates closed loop, go to step 12 . If scan tool does not indicate closed loop, go to next step.
4. Turn ignition on, with engine off. Disconnect O2S 1 connector. Connect a jumper wire between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is less than 50 mV, go to next step. If voltage is not less than 50 mV, go to step 6 .
5. Turn ignition off. Inspect O2S 1 harness connector for faulty terminals or poor connection. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to step 9 .
6. Turn ignition on, with engine off. Disconnect jumper wire. Using DVOM, measure voltage between ground and sensor signal circuit terminal at O2S 1 harness connector. If voltage is greater than 600 mV, go to step 10 . If voltage is not greater than 600 mV, go to next step.
7. If voltage reading is less than 300 mV, go to step 11 . If voltage reading is not less than 300 mV, go to next step.
8. Replace PCM. Program PCM using required equipment. After repairs, go to step 12 .
9. Replace oxygen sensor. After repairs, go to step 12 .
10. Check O2S 1 ground circuit for open or poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 8 .
11. Check O2S 1 signal circuit for open or poor connection at PCM. Repair as necessary. After repairs, go to next step. If circuit is okay, go to step 8 .
12. Reconnect oxygen sensor. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0134. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0134: O2S 1 CIRCUIT - INSUFFICIENT ACTIVITY (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies about .45 volt to Oxygen Sensor 1 (O2S 1). The O2S 1 supplies a varying voltage from about one volt when exhaust is rich to about .10 volt when exhaust is lean. PCM monitors and stores sensor voltage information and evaluates the voltage samples to determine amount of time sensor voltage is out of range. If PCM detects O2S 1 voltage remains at or about .45 volt for an extended period, DTC P0134 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 3 gm/s.
3. ECT is greater than 158°F (70°C).
4. TP sensor angle is 8-56 percent for 20 seconds.
5. Engine run time is greater than 30 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Warm engine to normal operating temperature. Operate engine to 1200 RPM for 2 minutes. Using scan tool, monitor HO2S voltage parameter. HO2S voltage should be varying between 400-500 mV. If voltage is varying out of specified range, go to next step. If voltage is not varying out of range, go to step 4 .
3. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this DTC failed in this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed in this ignition cycle, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Check for exhaust leaks, improperly installed HO2S or faulty wiring. Repair as necessary. After repairs, go to step 13 . If no problems were found, go to next step.
5. Turn ignition off. Disconnect HO2S harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between chassis ground and HO2S signal circuit at harness connector. If voltage reading is about 250 mV, go to next step. If voltage is not about 450 mV, go to step 8 .
6. Using a jumper wire, jumper HO2S harness connector terminals. Using scan tool, observe HO2S voltage. Voltage reading should be about zero millivolt. If voltage reading is as specified, go to step 9 . If voltage reading is not as specified, go to next step.
7. Check HO2S low circuit for open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
8. Check HO2S signal circuit for open or high resistance. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 11 .
9. Check for poor connections at HO2S connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
10. Check for alcohol contamination in fuel, improper use of RTV sealant or faulty HO2S. Repair as necessary. After repairs, go to step 13 .
11. Check for poor connections at PCM connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
12. Replace PCM. Program PCM using required equipment. After repairs, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, repeat step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent ground in signal wire between sensor connector and sensor. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damaged, replace oxygen sensor.

DTC P0137: HO2S 2 CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

The Heated Oxygen Sensor 2 (HO2S 2), located rear of catalytic converter, produces an output signal relative to oxygen storage capacity of catalytic converter. HO2S 2 signal is less active than signal produced by front oxygen sensor. DTC P0137 will set if HO2S 2 voltage remains less than 22 mV for 150 seconds.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 5.5 gm/s.
3. ECT is greater than 104°F (40°C).
4. TP sensor angle is 5-50 percent for 4 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe HO2S 2 voltage. If voltage is less than 200 mV, go to step 4 . If voltage is not less than 200 mV, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe HO2S 2 voltage. If voltage is less than 40 mV, go to next step. If voltage is not less than 40 mV, go to step 8 .
4. Turn ignition off. Disconnect HO2S 2 connector. Connect a jumper wire between ground and ground circuit terminal at HO2S 2 harness connector. Turn ignition on, with engine off. If voltage is 350-550 mV, go to step 7 . If voltage is not 350-550 mV, go to next step.
5. Turn ignition off. Disconnect PCM harness connectors. Check HO2S 2 signal circuit for a short to ground or a short to sensor ground circuit. Repair as necessary. After repairs, go to step 8 . If circuit is okay, go to next step.
6. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 8 .
7. Replace HO2S 2. After repairs, go to next step.
8. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0137. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
9. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Inspect exhaust system for leaks. Check oxygen sensor pigtail wire for breaks, contamination or grounding on exhaust manifold. Check for intermittent short to ground in HO2S 2 signal circuit wire. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0138: HO2S 2 CIRCUIT - VOLTAGE HIGH

Note. For circuit reference, See WIRING DIAGRAMS article.

The Heated Oxygen Sensor 2 (HO2S 2), located at rear of catalytic converter, produces an output signal relative to oxygen storage capacity of catalytic converter. HO2S 2 signal is less active than signal produced by front oxygen sensor. If HO2S 2 voltage remains greater than 1042 mV for 50-75 seconds, DTC P0138 will set.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 5.5 gm/s.
3. ECT is greater than 104°F (40°C).
4. TP sensor angle is 5-50 percent for 4 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, observe HO2S 2 voltage. If voltage is greater than 1042 mV, go to step 4 . If voltage is not greater than 1042 mV, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, observe HO2S 2 voltage. If voltage is greater than 1042 mV, go to next step. If voltage is not greater than 1042 mV, go to step 9 .
4. Turn ignition off. Disconnect HO2S 2 harness connector. Disconnect PCM harness connectors. Using a DVOM, measure voltage between ground and signal circuit terminal at HO2S 2 harness connector. If voltage is zero volts, go to next step. If voltage is not zero volts, go to step 6 .
5. Reconnect PCM harness connectors. Turn ignition on, engine off. Using a jumper wire, jumper HO2S 2 ground circuit and signal circuit to ground. If voltage is less than 100 mV, go to step 7 . If measured voltage is not less than 100 mV, go to step 8 .
6. Repair short to voltage in HO2S 2 signal circuit. After repairs, go to step 9 .
7. Replace HO2S 2. After repairs, go to step 9 .
8. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
9. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0138. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
10. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks and contamination. Check for intermittent short to voltage in HO2S 2 ground circuit wire. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. Check for an overly rich condition or contaminated HO2S 2.

DTC P0140: HO2S 2 CIRCUIT - INSUFFICIENT ACTIVITY

Note. For circuit reference, See WIRING DIAGRAMS article.

The Heated Oxygen Sensor 2 (HO2S 2), located at rear of catalytic converter, produces an output signal relative to oxygen storage capacity of catalytic converter. HO2S 2 signal is less active than signal produced by front oxygen sensor. DTC P0140 will set if HO2S 2 signal voltage remains at 425-460 mV for a predetermined amount of time.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0440, P0442, P0446, P0506, P0507, P0601, P0602 or P1441 are not set.
2. Airflow is greater than 5.5 gm/s.
3. ECT is greater than 104°F (40°C).
4. TP sensor angle is 4-56 percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Ensure engine is at normal operating temperature. Start engine. Increase engine speed to 1200 RPM for 2 minutes. Observe HO2S 2 voltage. If voltage is 425-460 mV, go to step 4 . If voltage is not 425-460 mV, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Observe HO2S 2 voltage. If voltage is 425-460 mV, go to next step. If voltage is not 425-460 mV, go to step 11 .
4. Turn ignition on, with engine off. Disconnect HO2S 2 harness connector. Connect a jumper wire between ground and signal circuit and ground circuit terminals at HO2S 2 harness connector. If voltage is less than 100 mV, go to next step. If voltage is not less than 100 mV, go to step 6 .
5. Turn ignition off. Check for open or poor connection at HO2S 2 harness connector. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to step 7 .
6. Turn ignition off. Remove jumper wire. Using a test light connected to battery positive, probe ground circuit at HO2S 2 harness connector. If test light illuminates, go to step 8 . If test light does not illuminate, go to step 9 .
7. Replace HO2S 2. After repairs, go to step 11 .
8. Check HO2S 2 signal circuit for an open or poor connection. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to step 10 .
9. Repair open in HO2S 2 ground circuit. After repairs, go to step 11 .
10. Replace PCM. Program replacement PCM using required equipment. After repairs, go to next step.
11. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0140. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
12. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks and contamination. An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. Check for intermittent open in HO2S 2 signal circuit wire. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0141: HO2S 2 HEATER CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Heated Oxygen Sensor 2 (HO2S 2), located at rear of catalytic converter, produces an output signal relative to oxygen storage capacity of catalytic converter. HO2S 2 signal is less active than signal produced by front Oxygen Sensor 1 (O2S 1). DTC P0141 will set if HO2S 2 voltage increase is less than 150 mV in 100-190 seconds.

For duplication of DTC, ensure ECT and IAT is less than 113°F (45°C), difference between ECT and IAT is less than 45°F (7°C), and TP angle is less than 18 percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step. NOTE: If engine has been operating, turn ignition off and allow engine to cool down for about 1/2 hour before proceeding.
2. Turn ignition on, with engine off. Using scan tool, observe HO2S 2 voltage reading. If voltage gradually changes toward zero or one volt, go to step 13 . If voltage does not gradually change toward zero or one volt, go to next step.
3. Disconnect HO2S 2 harness connector. Connect a test light between ground and ignition feed circuit terminal at HO2S 2 harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 5 .
4. Connect a test light between ground circuit and ignition feed circuit terminals at HO2S 2 harness connector. If test light illuminates, go to step 6 . If test light does not illuminate, go to step 7 .
5. Remove and inspect fuse for HO2S 2 ignition feed circuit. If fuse is open, go to step 8 . If fuse is okay, go to step 9 .
6. Turn ignition off. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair as necessary. After repairs, go to step 13 . If connector is okay, go to step 10 .
7. Turn ignition off. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair as necessary. After repairs, go to step 13 . If connector is okay, go to step 11 .
8. Check for short to ground in HO2S 2 ignition feed circuit. Repair as necessary. After repairs, replace fuse and go to step 13 .
9. Turn ignition off. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair as necessary. After repairs, go to step 13 .
10. Replace HO2S 2. After repairs, go to step 13 .
11. Repair open in ground circuit. After repairs, go to step 13 .
12. Repair open in ignition feed circuit. After repairs, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0141. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks and contamination. An intermittent problem can be caused by misrouted harness, rubbed through wire insulation or broken wire inside insulation. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0141: HO2S 2 HEATER CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Heated Oxygen Sensor 2 (HO2S 2), located at rear of catalytic converter, produces an output signal relative to oxygen storage capacity of catalytic converter. HO2S 2 signal is less active than signal produced by front Oxygen Sensor 1 (O2S 1). DTC P0141 will set if HO2S 2 voltage increase is less than 150 mV in 100-190 seconds.

For duplication of DTC, ensure ECT and IAT is less than 113°F (45°C), difference between ECT and IAT is less than 45°F (7°C), and TP angle is less than 18 percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step. NOTE: If engine has been operating, turn ignition off and allow engine to cool down for about 1/2 hour before proceeding.
2. Turn ignition on, with engine off. Using scan tool, observe HO2S 2 voltage reading. If voltage gradually changes toward zero or one volt, go to see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If voltage does not gradually change toward zero or one volt, go to next step.
3. Remove and inspect ERLS fuse for HO2S 2 ignition feed circuit. If fuse is open, go to next step. If fuse is okay, go to step 5 .
4. Turn ignition off. Allow engine to cool down for 10 minutes. Disconnect HO2S 2 harness connector. Using a DVOM, Check resistance between HO2S 2 harness connector ignition feed and ground circuits. If resistance is 4-6 ohms, go to step 9 . If resistance is not 4-6 ohms, go to step 10 .
5. Turn ignition off. Disconnect HO2S 2 harness connector. Turn ignition on, with engine off. Using a test light connected to chassis ground, probe test light to sensor harness connector ignition feed circuit terminal. If test light illuminates, go to next step. If test light doe snot illuminate, go to step 7 .
6. Connect test light between sensor harness connector ground and ignition feed circuit. If test light illuminates, go to step 10 . If test light does not illuminate, go to step 8 .
7. Turn ignition off. Inspect HO2S 2 ignition feed circuit for open or poor connections. Repair as necessary. After repairs or inspection of circuit, go to step 11 .
8. Turn ignition off. Check HO2S 2 ground circuit for open or poor connections. Repair as necessary. After repairs or inspection of circuit, go to step 11 .
9. Repair short to ground in HO2S 2 ignition feed circuit. Replace fuse. After repairs, go to step 11 .
10. Replace HO2S 2. Check HO2S 2 fuse. Replace fuse as necessary. After repairs, go to next step.
11. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
12. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Check oxygen sensor pigtail wire for breaks and contamination. An intermittent problem can be caused by misrouted harness, rubbed through wire insulation or broken wire inside insulation. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

PCM monitors oxygen sensor signal voltage and adjusts fuel delivery based on signal voltage. A change made to fuel delivery is indicated by the long and short term fuel trim values. Ideal fuel trim value is about 128 (zero percent).

A fuel trim value of greater than 128 indicates that PCM is adding fuel to compensate for a lean condition. A fuel trim value less than 128 indicates that PCM is reducing amount of fuel to compensate for rich condition. This DTC will set if PCM detects an excessively lean condition.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131-P0134, P0200, P0300-P0304, P0325, P0335, P0341, P0342, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133 or P1441 are not set.
2. IAT is -13 to 175°F (-25 to 115°C).
3. ECT is 140-239°F (60-115°C).
4. Engine speed is 550-3400 RPM.
5. Vehicle speed is less than 82 MPH.
6. MAP is greater than 28 kPa.
7. BARO is greater than 72 kPa.
8. EVAP purge is not occurring.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Start and warm engine to normal operating temperature. Ensure system is in closed loop. Using scan tool, select FUEL TRIM INDEX. If fuel trim index is less than 29 percent, go to next step. If fuel trim index is not less than 29 percent, go to step 5 .
4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If fuel trim index is less than 29 percent, go to step 16 . If fuel trim index is not less than 29 percent, go to next step.
5. Check vacuum hoses for splits, kinks and proper routing. Check PCV valve for proper installation. Check for fuel contamination. Check PCM and sensor grounds. Check O2S 1 for correct installation and ensure O2S 1 wiring is not in contact with exhaust manifold. If no problems are found, go to next step. If any problem is found, go to step 7 .
6. Disconnect MAP sensor harness connector. Operate vehicle in closed loop while monitoring FUEL INDEX TRIM. If fuel trim index is less than 29 percent, go to step 15 . If fuel trim index is not less than 29 percent, go to step 9 .
7. Repair fault that was detected in step 5 . Operate vehicle in closed loop while monitoring FUEL INDEX TRIM. If fuel trim index is less than 29 percent, go to next step. If fuel trim index is not less than 29 percent, go to step 9 .
8. Lean condition is not present at this time. If a driveability problem exists, see appropriate TROUBLE SHOOTING - NO CODES article. If no driveability problem exist, go to step 16 .
9. Check vacuum hoses for splits, kinks and proper routing. Check throttle body, intake manifold and injector "O" rings for vacuum leaks. Repair as necessary. After repairs, go to step 16 . If no problem is found, go to next step.
10. Start engine and allow it to idle. Using scan tool, check IAC count. If IAC count is greater than 5, go to next step. If IAC count is not greater than 5, go to step 12 .
11. Check for fuel contamination. Repair as necessary. After repairs, go to step 16 . If fuel is okay, go to step 13 .
12. Turn ignition off. Perform DTC P0506 or P0507 to check IAC valve performance. Repair as necessary. After repairs, go to step 16 . If IAC valve is okay, go to next step.
13. Connect a fuel pressure gauge to fuel system. Cycle ignition switch 2-3 times. With fuel pump running, observe fuel pressure. If fuel pressure is 42-55 psi (290-379 kPa), go to next step. If fuel pressure is not as specified, repair fuel system as necessary. See appropriate SYSTEM & COMPONENT TESTING article.
14. Ensure engine is at normal operating temperature. Start engine and allow it to idle. Observe fuel pressure. Fuel pressure noted in step 13 should drop 3-10 psi (21-69 kPa). If fuel pressure is as specified, perform injector balance test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If fuel pressure is not as specified, see BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
15. Replace MAP sensor. After repairs, go to next step.
16. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC P0171. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
17. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

If DTC P0171 cannot be duplicated, problem may have been caused by engine running out of fuel. A fuel delivery malfunction will cause DTC to set. Check all items that can cause a lean condition.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

PCM monitors oxygen sensor signal voltage and adjusts fuel delivery based on signal voltage. A change made to fuel delivery is indicated by the long and short term fuel trim values. Ideal fuel trim value is about 128 (zero percent).

A fuel trim value of greater than 128 indicates that PCM is adding fuel to compensate for a lean condition. A fuel trim value less than 128 indicates that PCM is reducing amount of fuel to compensate for rich condition. This DTC will set if PCM detects an excessively lean condition.

For duplication of DTC, ensure

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131-P0134, P0200, P0200-P0204, P0300, P0325, P0335, P0341, P0342, P0446, P0502, P0503, P0506, P0507, P0601, P0602, P1133 , P1404 or P1441 are not set.
2. IAT is -13 to 175°F (-25 to 115°C).
3. ECT is 140-239°F (60-115°C).
4. Engine speed is 550-3400 RPM.
5. Vehicle speed is less than 82 MPH.
6. MAP is greater than 28 kPa.
7. BARO is greater than 72 kPa.
8. EVAP purge is not occurring.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Start and warm engine to normal operating temperature. Ensure system is in closed-loop. Using scan tool, select FUEL TRIM INDEX. If fuel trim index is less than 32 percent, go to next step. If fuel trim index is not less than 32 percent, go to step 5 .
4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If fuel trim index is less than 32 percent, go to see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If fuel trim index is not less than 32 percent, go to next step.
5. Check vacuum hoses for splits, kinks and proper routing. Check PCV valve for proper installation. Check for fuel contamination. Check PCM and sensor grounds. Check O2S 1 for correct installation and ensure O2S 1 wiring is not in contact with exhaust manifold. If no problems are found, go to next step. If any problem is found, go to step 7 .
6. Disconnect MAP sensor harness connector. Operate vehicle in closed-loop while monitoring FUEL INDEX TRIM. If fuel trim index is less than 32 percent, go to step 12 . If fuel trim index is not less than 32 percent, go to step 8 .
7. Repair fault as necessary. After repairs, operate vehicle in closed-loop while monitoring FUEL INDEX TRIM. If fuel trim index is less than 32 percent, go to step 13 . If fuel trim index is not less than 32 percent, go to next step.
8. Start and operate engine at idle. Check vacuum for leaks at throttle body, intake manifold and injector "O" rings. Repair as necessary. After repairs, go to step 13 . If no problem is found, go to next step.
9. Start and operate engine at idle. Using scan tool, check IAC count. If IAC count is greater than 5, go to next step. If IAC count is not greater than 5, go to step 13 .
10. Perform IAC valve performance test. Refer to «DTC P0506: IDLE SPEED LOW (2.4L "J" & "N" BODIES)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0506-idle-speed-low-24l) and «DTC P0507: IDLE SPEED HIGH (2.4L "N" BODY)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0507-idle-speed-high-24l) . If a problem is found, repair as necessary. After repairs, go to step 13 . If IAC valve is okay, go to next step.
11. Perform fuel system diagnosis. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary. After repairs, go to step 13 .
12. Replace MAP sensor. After repairs, go to next step.
13. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates this test ran and passed, go to next step. If scan tool does not indicate this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

If this DTC cannot be duplicated, problem may have been caused by engine running out of fuel. A fuel delivery malfunction will cause DTC to set. Check all items that can cause a lean condition, such as a plugged fuel filter.

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0172: FUEL TRIM SYSTEM RICH

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM monitors oxygen sensor signal voltage and adjusts fuel delivery based on signal voltage. A change made to fuel delivery is indicated by the long and short term fuel trim values. Ideal fuel trim value is about 128 (zero percent).

A fuel trim value greater than 128 indicates that PCM is adding fuel to compensate for a lean condition. A fuel trim value less than 128 indicates that PCM is reducing amount of fuel to compensate for rich condition. DTC will set if PCM detects an excessively rich condition.

For duplication of DTC, ensure

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0335, P0341, P0342, P0401, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0602, P1404, P1133 or P1441 are not set.
2. IAT is -13 to 175°F (-25 to115°C).
3. ECT is 140-239°F (60-115°C).
4. MAP greater than 26 kPa.
5. Vehicle speed is less than 72 MPH.
6. Engine speed is 550-3400 RPM.
7. Fuel trim index is less than 70 percent.
8. EVAP purge is not occurring.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Start and warm engine to normal operating temperature. Ensure system is in closed loop. Using scan tool, select FUEL TRIM INDEX. If fuel trim index is not greater than - 46 percent, go to next step 5 . If fuel trim index is greater than - 46 percent, go to next step.
4. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If fuel trim index is greater than - 46 percent, go to step 21 . If fuel trim index is not greater than - 46 percent, go to next step.
5. Turn ignition off. Check air filter. Replace filter as necessary. After repairs, go to step 21 . If air filter is okay, go to next step.
6. Check for collapsed or restricted air intake duct. Repair as necessary. After repairs, go to step 21 . If air intake duct is okay, go to next step.
7. Inspect throttle body inlet from damage of foreign objects that may partially block airflow. Repair as necessary. After repairs, go to step 21 . If no repair is necessary, go to next step.
8. Inspect throttle body bore, throttle plate and IAC passages for coking and foreign objects. Repair as necessary. After repairs, go to step 21 . If no repair is necessary, go to next step.
9. Start engine. Ensure all accessories are off. Note idle condition. If idle is low or unstable, go to next step. If idle is okay, go to step 12 .
10. Using scan tool, check IAC count. If IAC count is less than 100, go to step 12 . If IAC count is not less than 100, go to next step.
11. Disconnect MAP sensor harness connector. Start and warm engine to normal operating temperature. Ensure system is in closed loop. Using scan tool, select FUEL TRIM INDEX display. If fuel trim index is greater than - 46 percent, go to step 20 . If fuel trim index is not greater than - 46 percent, go to next step.
12. Turn ignition off. Perform IAC calve performance test, Refer to «DTC P0506: IDLE SPEED LOW (2.4L "J" & "N" BODIES)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0506-idle-speed-low-24l) and «DTC P0507: IDLE SPEED HIGH (EXCEPT 2.4L "N" BODY)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0507-idle-speed-high-except) or «DTC P0507: IDLE SPEED HIGH (2.4L "N" BODY)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0507-idle-speed-high-24l) . Repair as necessary. After repairs, go to step 21 . If IAC valve is okay, go to next step.
13. Disconnect fuel pressure regulator vacuum hose. Check vacuum hose for presence of fuel. If fuel is present, replace fuel pressure regulator. After repairs, go to step 21 . If fuel pressure regulator is okay, go to next step.
14. Turn ignition on, with engine off. Using scan tool, monitor THROT POSITION display while slowly depressing accelerator pedal. If reading increases steadily from minimum voltage to maximum voltage at wide open throttle, go to next step. If reading does not increase steadily from minimum voltage to maximum voltage, go to step 19 .
15. Diagnose fuel system. See appropriate BASIC DIAGNOSTIC PROCEDURES article. Repair fuel system as necessary. After repairs, go to step 21 . If fuel system is okay, go to next step.
16. Check fuel evaporation system for proper operation. Ensure canister purge solenoid is functioning properly. See appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary. After repairs, go to step 21 . If fuel evaporation system is functioning properly, go to next step.
17. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article. Repair as necessary. After repairs, go to step 21 . If no problems are found, go to next step.
18. Remove and inspect O2S 1 for silicone contamination. If contamination exists, a powdery White deposit on portion of sensor exposed to exhaust system will be present. If silicone contamination is present, locate and repair source of contamination. Replace O2S 1. After repairs, go to step 21 . If no contamination exists, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
19. Check TP sensor mounting screws. Tighten or replace screws as necessary. If mounting screws are okay, replace TP sensor. After repairs, go to step 21 .
20. Replace MAP sensor. After repairs, go to next step.
21. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
22. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

Disconnect and inspect PCM harness connector. Inspect for damaged pins, corrosion and loose wires. Check oxygen sensor wiring harness for intermittent. An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor.

DTC P0201: INJECTOR 1 CONTROL CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) has 4 injector driver circuits, one for each injector. PCM monitors current in each driver circuit by measuring a voltage drop through a fixed resistor and is able to control it. Current through each driver is allowed to rise to a peak or 2 amps to quickly open injectors. Current is then reduced to 1/2 amp to keep injector open. If current cannot reach 2 amps or injector driver is shorted to voltage, this DTC will set.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 1 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 8 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 14 .
7. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
8. Using a test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
9. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light does not illuminate, go to step 11 . If test light illuminates, go to step 12 .
10. Turn ignition off. Repair open in ignition feed circuit. After repairs, go to step 14 .
11. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 7 .
12. Turn ignition off. Repair short to voltage in fuel injector driver circuit. After repairs, go to step 14 .
13. Repair open or faulty connection in fuel injector driver circuit. After repairs, go to next step.
14. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
15. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0201: INJECTOR 1 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) controls the fuel injectors by using a ground circuit driver within the PCM. If an electrical malfunction occurs in the fuel injector circuit, DTC will set. DTC will set when injector current is less than one amp or is continuously high for about 7 seconds.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 1 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 7 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 13 .
7. Using test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
8. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 10 .
9. Turn ignition off. Repair open or poor connection in ignition feed circuit. After repairs, go to step 13 .
10. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 12 .
11. Turn ignition off. Check for short to voltage in fuel injector driver circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
13. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0202: INJECTOR 2 CONTROL CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) has 4 injector driver circuits, one for each injector. PCM monitors current in each driver circuit by measuring a voltage drop through a fixed resistor and is able to control it. Current through each driver is allowed to rise to a peak or 2 amps to quickly open injectors. Current is then reduced to 1/2 amp to keep injector open. If current cannot reach 2 amps or injector driver is shorted to voltage, this DTC will set.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 2 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 8 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 14 .
7. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
8. Using a test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
9. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light does not illuminate, go to step 11 . If test light illuminates, go to step 12 .
10. Turn ignition off. Repair open in ignition feed circuit. After repairs, go to step 14 .
11. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 7 .
12. Turn ignition off. Repair short to voltage in fuel injector driver circuit. After repairs, go to step 14 .
13. Repair open or faulty connection in fuel injector driver circuit. After repairs, go to next step.
14. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
15. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0202: INJECTOR 2 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) controls the fuel injectors by using a ground circuit driver within the PCM. If an electrical malfunction occurs in the fuel injector circuit, DTC will set. DTC will set when injector current is less than one amp or is continuously high for about 7 seconds.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 2 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 7 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 13 .
7. Using test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
8. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 10 .
9. Turn ignition off. Repair open or poor connection in ignition feed circuit. After repairs, go to step 13 .
10. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 12 .
11. Turn ignition off. Check for short to voltage in fuel injector driver circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
13. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0203: INJECTOR 3 CONTROL CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) has 4 injector driver circuits, one for each injector. PCM monitors current in each driver circuit by measuring a voltage drop through a fixed resistor and is able to control it. Current through each driver is allowed to rise to a peak or 2 amps to quickly open injectors. Current is then reduced to 1/2 amp to keep injector open. If current cannot reach 2 amps or injector driver is shorted to voltage, this DTC will set.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 3 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 8 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 14 .
7. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
8. Using a test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
9. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light does not illuminate, go to step 11 . If test light illuminates, go to step 12 .
10. Turn ignition off. Repair open in ignition feed circuit. After repairs, go to step 14 .
11. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 7 .
12. Turn ignition off. Repair short to voltage in fuel injector driver circuit. After repairs, go to step 14 .
13. Repair open or faulty connection in fuel injector driver circuit. After repairs, go to next step.
14. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
15. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0203: INJECTOR 3 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) controls the fuel injectors by using a ground circuit driver within the PCM. If an electrical malfunction occurs in the fuel injector circuit, DTC will set. DTC will set when injector current is less than one amp or is continuously high for about 7 seconds.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 3 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 7 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 13 .
7. Using test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
8. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 10 .
9. Turn ignition off. Repair open or poor connection in ignition feed circuit. After repairs, go to step 13 .
10. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 12 .
11. Turn ignition off. Check for short to voltage in fuel injector driver circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
13. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0204: INJECTOR 4 CONTROL CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) has 4 injector driver circuits, one for each injector. PCM monitors current in each driver circuit by measuring a voltage drop through a fixed resistor and is able to control it. Current through each driver is allowed to rise to a peak or 2 amps to quickly open injectors. Current is then reduced to 1/2 amp to keep injector open. If current cannot reach 2 amps or injector driver is shorted to voltage, this DTC will set.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 4 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 8 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 7 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 14 .
7. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 14 .
8. Using a test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 10 .
9. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light does not illuminate, go to step 11 . If test light illuminates, go to step 12 .
10. Turn ignition off. Repair open in ignition feed circuit. After repairs, go to step 14 .
11. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 7 .
12. Turn ignition off. Repair short to voltage in fuel injector driver circuit. After repairs, go to step 14 .
13. Repair open or faulty connection in fuel injector driver circuit. After repairs, go to next step.
14. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
15. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0204: INJECTOR 4 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) controls the fuel injectors by using a ground circuit driver within the PCM. If an electrical malfunction occurs in the fuel injector circuit, DTC will set. DTC will set when injector current is less than one amp or is continuously high for about 7 seconds.

For duplication of DTC, ensure engine is running and battery voltage is greater than 9 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, see NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
3. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light on No. 4 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes on all injectors, perform injector coil test. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If test light does not flash on all injectors, go to next step.
4. If test light did not flash in step 3 but was on steady, go to next step. If test light did not flash in step 3 and was off, go to step 7 .
5. Remove injector test light from affected circuit. Turn ignition off. Disconnect PCM harness connector containing affected fuel injector circuit. Using a test light connected to battery positive, probe affected fuel injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 12 .
6. Repair short to ground in fuel injector driver circuit. After repairs, go to step 13 .
7. Using test light connected to ground, probe ignition feed circuit terminal at affected fuel injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 9 .
8. With test light still connected to ground, probe fuel injector driver circuit terminal at affected injector harness connector. Crank engine. If test light illuminates, go to step 11 . If test light does not illuminate, go to step 10 .
9. Turn ignition off. Repair open or poor connection in ignition feed circuit. After repairs, go to step 13 .
10. Turn ignition off. Check for open or faulty connection in fuel injector driver circuit. If a problem is found, go to step 13 . If circuit is okay, go to step 12 .
11. Turn ignition off. Check for short to voltage in fuel injector driver circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to next step.
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
13. Reconnect all fuel injector harness connectors. Using scan tool, clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function, and then enter DTC which was set. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An injector that is shorted to voltage or is disconnected while engine is operating will cause this DTC to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0300: ENGINE MISFIRE DETECTED (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL) indicating that catalytic converter damage is possible. Conditions for setting this DTC

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 or P1621 not set.
2. Misfire total is 12 counts or more.
3. Engine speed is 469-6406 RPM.
4. Battery voltage 9-17 volts.
5. ECT 20-254°F (-7 to123°C).
6. Engine run time longer than 15 seconds.
7. TP sensor angle has not changed more than 8 percent in one second.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If DTC P0200 is also set, diagnose that DTC before proceeding. If DTC P0200 is not set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 31 . If no problems are found, go to next step.
4. Start and allow engine to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If any MISFIRE CURRENT counters are incrementing, go to next step. If any MISFIRE CURRENT counters are not incrementing, go step 6 .
5. If all counters are equal (within a percentage of each other), go to step 7 . If counters are not equal (within a percentage of each other), go to step 11 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If any of MISFIRE CURRENT counters are incrementing, go to step 5 . If MISFIRE CURRENT counters are not incrementing, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
7. Turn ignition off. Install fuel pressure gauge. Start engine and allow it to idle. If fuel pressure is 41-47 psi (2.9-3.3 kg/cm 2 ), go to next step. If fuel pressure is not 41-47 psi (2.9-3.3 kg/cm 2 ), see BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
8. Check for fuel contamination. If fuel is contaminated, go to step 10 . If fuel is not contaminated, go to next step.
9. Check for a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 31 .
10. Replace contaminated fuel. After repairs, go to step 31 .
11. Turn ignition off. Disconnect fuel injector harness connector. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) to spark plug jumper for each cylinder, one at a time. Disconnect spark plug boot from companion cylinder at ignition coil housing and install a jumper wire between ground and spark plug connector at ignition coil housing (1-4 or 2-3). Crank engine and check for spark. If spark is present at all cylinders, go to next step. If spark is not present at one or more cylinders, go to step 20 .
12. Check for faulty spark plugs. Replace defective spark plug(s) as necessary. After repairs, go to step 31 . If spark plugs are okay, go to next step.
13. Turn ignition off. Disconnect fuel injector connectors from injectors. Install an injector test light on injector harness connector for cylinders that had misfired. Crank engine and note test light. If injector test light blinks, go to next step. If injector test light does not blink, go to step 15 .
14. Perform fuel injector test. See appropriate SYSTEM & COMPONENT TESTING article. If injectors are okay, go to step 9 . If injectors are not okay, go to step 16 .
15. Disconnect injector test light. Using a standard test light connected to ground, probe ignition feed of injector harness connector for each affected/misfiring injector. Crank engine. If test light illuminates, go to step 17 . If test light does not illuminate, go to step 19 .
16. Replace any faulty fuel injector(s). After replacing injector(s), go to step 31 .
17. Check affected fuel injector driver circuit(s) for an open, short to ground or short to voltage. If problem is found, go to next step. If circuit is okay, go to step 28 .
18. Repair as necessary. After repairs, go to step 31 .
19. Repair open ignition feed circuit between fuel injector harness connector and fuel injector. After repairs, go to step 31 .
20. Check resistance of spark plug cable on affected cylinder. If resistance is less than 30,000 ohms, go to next step. If resistance is not less than 30,000 ohms, go to step 28 .
21. Turn ignition off. Disconnect PCM harness connector. Reconnect Spark Tester (J-26792) on affected spark plug wire. Turn ignition on. Connect a fused jumper wire to battery voltage. Momentarily touch jumper to affected IC circuit at PCM harness connector. DO NOT leave jumper wire connected for longer than 5 seconds. If spark is present at spark tester when jumper is removed from IC circuit, go to step 26 . If spark is not present at spark tester when jumper is removed from IC circuit, go to next step.
22. Turn ignition off. Disconnect ICM harness connector. Check affected IC circuit for an open or short. Repair as necessary. After repairs, go to step 30 . If circuit is okay, go to next step.
23. Remove ignition coil from cylinder that did no have a spark. Check secondary coil resistance. If coil resistance is 5000-8000 ohms, go to next step. If coil resistance is not 5000-8000 ohms, go to step 29 .
24. Install a known-good ignition coil. Reconnect ICM harness connector. Connect spark tester to affected cylinder. Turn ignition on. Momentarily touch jumper wire to affected IC circuit at PCM connector. If spark is present at spark tester, go to step 30 . If spark is not present at spark tester, go to next step.
25. Check for poor connection at ICM. Repair a necessary. If connection is okay, replace ICM. After replacing ICM, go to step 30 .
26. Check for poor PCM connection. Repair as necessary. After repairs, go to step 30 . If connection is okay, go to next step.
27. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 30 .
28. Replace spark plug cables. After replacing spark plug cables, go to step 30 .
29. Replace faulty ignition coil. After replacing ignition coil, go to next step.
30. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0300. If scan tool indicates that test RAN AND PASSED, go to next step. If scan tool does not indicate that test RAN AND PASSED, repeat step 2 .
31. If any other DTCs are set, diagnose affected DTCs. If no other DTCs are set, system is okay.

A intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0300: ENGINE MISFIRE DETECTED (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL) indicating that catalytic converter damage is possible. Conditions for setting this DTC

1. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133 and P1621 not set.
2. Misfire total is 8 counts or more.
3. Engine speed is 469-6400 RPM.
4. Battery voltage 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. Engine running longer than 5 seconds.
7. TP sensor angle has not increased more than 8 percent in one second.
8. TP sensor angle has not decreased more than 1.5 percent in one second.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for any injector related DTC. If an injector related DTC is set, diagnose affected DTC before proceeding. If no injector related DTC is set, go to next step.
3. Turn ignition off. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 28 . If no problems were found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If any MISFIRE CURRENT counters are incrementing, go to step 6 . If MISFIRE CURRENT counters are not incrementing, go to next step.
5. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If any of MISFIRE CURRENT counters are incrementing, go to next step. If MISFIRE CURRENT counters are not incrementing, go to step 28 .
6. If all counters are equal (within one percent of each other), go to next step. If all counters are not equal, go to step 11 .
7. Turn ignition off. Install fuel pressure gauge. Start engine and allow it to idle. Fuel pressure should be 42-55 psi (2.9-3.9 kg/cm 2 ). If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, see BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article.
8. Check for fuel contamination. If fuel is contaminated, go to step 10 . If fuel is not contaminated, go to next step.
9. Check for a basic engine problem (compression, cam timing, throttle body leak, restricted airflow etc.). Repair as necessary. After repairs, go to step 28 .
10. Replace contaminated fuel. After repairs, go to step 28 .
11. Turn ignition off. Disconnect all fuel injector harness connector. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) to spark plug jumper for each cylinder, one at a time. Disconnect spark plug boot from companion cylinder at ignition coil housing and install a fused jumper wire between ground and spark plug connector at ignition coil housing (1-4 or 2-3). Crank engine and check for spark. If spark is present at all cylinders, go to next step. If spark is not present at one or more cylinders, go to step 14 .
12. Check for faulty spark plugs. Replace defective spark plug(s) as necessary. After repairs, go to step 28 . If spark plugs are okay, go to step 9 .
13. Turn ignition off. Disconnect PCM harness connector. Remove boot assemblies from companion cylinder of affected ignition coil. Connect a fused jumper wire to ground and companion cylinder spark plug connector ignition coil housing. Turn ignition on, with engine off. Using a test light connected to battery positive, momentarily touch the affected IC circuit at the PCM harness connector (terminals C1-25 or C1-26). A spark should be present when test light is removed from IC circuit. If spark is present, go to step 25 . If spark is not present, go to next step.
14. Turn ignition off. Remove spark plug boot assemblies from affected coil at IC housing. Connect a DVOM between the secondary ignition coil terminals (spark plug connectors 1-4 or 2-3) at ignition coil housing. Resistance should be 4000-8000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 16 .
15. Remove ignition coil housing from cover. Disconnect ignition coil harness connector at ICM. Using another test light connected to battery voltage, probe coil control terminal that did not have a spark at the ICM. Turn ignition on, with engine off. Momentarily touch test light to the affected IC circuit at the PCM harness connector (terminals C1-25 or C1-26). Watch the other test light. If the other test light blinked, go to step 17 . If the other test light did not blink, go to step 18 .
16. Remove ignition coil housing. Disconnect ignition coil connector from ICM. Remove ignition coil from housing. Check resistance between ignition coil secondary terminals. Resistance should be 4000-8000 ohms. If resistance is as specified, go to step 20 . If resistance is not as specified, go to step 22 .
17. Turn ignition off. Repair open, shorted or poor connection at ignition coil or ICM. Check for short to ignition coil. Repair as necessary. After repairs, go to step 28 . If circuits and connections are okay, go to step 19 .
18. Turn ignition off. Disconnect ICM 11-pin harness connector. Check affected circuit IC input circuit between ICM and PCM for an open circuit, short to ground or short to voltage. Repair as necessary. After repairs, go to step 28 . If circuit is okay, go to step 24 .
19. Remove ignition coils from housing. Disconnect ignition coil harness connector from ignition coils. Reconnect ignition coil harness connector to ICM. Connect a test light to ground. Turn ignition on, with engine off. Using test light, probe ignition feed circuit to ignition coils at both coil harness connector terminal "B". If test light illuminates on both circuits, go to next step. If test light does not illuminate on both circuits, go to step 23 .
20. Check affected spark plug boot assemblies, ignition coil springs or ignition coil housing. Repair or replace or necessary. After repairs, go to step 28 . If no problem is found, go to next step.
21. Check spark plug boot. Repair or replace as necessary. After repairs, go to step 28 . If boot is okay, go to next step.
22. Check PCM harness connector terminals for poor connections. Repair as necessary. After repairs, go to step 28 . If terminal connections are okay, replace affected ignition coil. After replacing ignition coil, go to step 28 .
23. Turn ignition off. Repair open in ignition feed circuit between cylinders No. 1-4 and No. 2-3 ignition coil harness connectors. After repairs, go to step 28 .
24. Replace ICM. After replacing ICM, go to step 28 .
25. Turn ignition off. Check PCM harness connector and connector terminals. If a problem is found, go to next step. If no problem is found, go to step 27 .
26. Repair connector or connector terminals. After repairs, go to step 28 .
27. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
28. Reinstall previously disconnected components. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates that test RAN AND PASSED, go to next step. If scan tool does not indicate that test RAN AND PASSED, repeat step 2 .
29. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

A intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0301: CYLINDER NO. 1 MISFIRE DETECTED (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL) indicating that catalytic converter damage is possible. Conditions for setting this DTC

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 and P1621 not set.
2. Misfire total is greater than 12 counts.
3. Engine speed is 469-6406 RPM.
4. Battery voltage is 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. Engine run time greater than 15 seconds.
7. TP sensor angle has not changed more than 8 percent in one second.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 6 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 1 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 1 counter is not incrementing, go to step 6 .
5. Turn ignition off. Disconnect fuel injector harness connector. Install Spark Tester (J-26792) to cylinder No. 1 spark plug wire. Remove spark plug wire No. 4 from ignition coil. Connect a jumper wire between ground and ignition coil tower (where spark plug wire No. 4 was). Crank engine and check for spark. If spark is present, go to step 8 . If spark is not present, go to step 9 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 1 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 1 counter is not incrementing, go to next step.
7. If a repair was made after visual inspection was performed in step 3 , go to step 30 . If no problems were found in visual inspection, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Remove spark plug from No. 1 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 1 counter is incrementing properly, go to step 13 . If MISFIRE CURRENT NO. 1 counter is not incrementing properly, go to step 22 .
9. Remove spark plug wire from cylinder No. 1. Using DVOM, check spark plug wire resistance. If resistance is less than 3000 ohms, go to next step. If resistance is not less than 3000 ohms, go to step 23 .
10. Remove ignition coil from cylinder that did not have spark. Check secondary resistance of coil. If resistance is 5000-8000 ohms, go to next step. If resistance is not 5000-8000 ohms, go to step 24 .
11. Replace coil with a known-good coil. Crank engine and check for spark. If spark is present, go to step 24 . If spark is not present, go to next step.
12. Disconnect and inspect Ignition Control Module (ICM) 6-pin connector. Repair as necessary. After repairs, go to step 30 . If connector is okay, go to step 25 .
13. Turn ignition off. Disconnect all fuel injector connectors. Install injector test light on injector harness connector for cylinder No. 1. Crank engine and observe test light. If test light flashes, go to next step. If test light does not flash, go to step 15 .
14. Perform INJECTOR BALANCE TEST. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injector No. 1 is okay, go to step 28 . If injector No. 1 is not okay, go to step 29 .
15. Remove injector test light. Connect a test light between ground and ignition feed terminal at No. 1 injector harness connector. Crank engine and observe test light. If test light is on, go to next step. If test light is off, go to step 27 .
16. Turn ignition off. Disconnect PCM harness connectors. With test light connected to ground, probe injector driver circuit terminal at No. 1 injector harness connector. If test light is off, go to next step. If test light is on, go to step 26 .
17. With test light connected to positive battery terminal, probe injector driver circuit terminal at No. 1 injector harness connector. If test light is off, go to next step. If test light is on, go to step 19 .
18. Inspect PCM connectors for damaged pins, corrosion and loose wires. If connectors are okay, go to step 20 . If connectors are not okay, go to step 21 .
19. Repair short to ground in cylinder No. 1 fuel injector driver circuit. After repairs, go to step 30 .
20. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 30 .
21. Repair connector or connections as necessary. After repairs, go to step 30 .
22. Replace spark plug. After replacing spark plug, go to step 30 .
23. Replace spark plug wire. After replacing spark plug wire, go to step 30 .
24. Replace ignition coil. After replacing ignition coil, go to step 30 .
25. Replace ICM. After replacing module, go to step 30 .
26. Repair short to voltage in cylinder No. 1 fuel injector driver circuit. After repairs, go to step 30 .
27. Repair open in ignition feed circuit. After repairs, go to step 30 .
28. Check for a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 30 .
29. Replace defective fuel injector. After replacing injector, go to next step.
30. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
31. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0301: CYLINDER NO. 1 MISFIRE DETECTED (2.4L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting this DTC are as follows

1. Misfire total is greater than 8 counts.
2. Engine speed is 469-6400 RPM.
3. Battery voltage 9-17 volts.
4. ECT 20-254°F (-7 to 123°C).
5. Engine run time is longer than 5 seconds.
6. TP sensor angle has not changed more than 8 percent in one second.
7. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133 and P1621 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 25 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 1 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 1 counter is not incrementing, go to step 6 .
5. Turn ignition off. Remove air cleaner outlet resonator assembly. Disconnect all fuel injector harness connectors. Disconnect ICM 11-pin harness connector. Temporarily remove ignition coil and ICM assembly. Reconnect ICM 11-pin harness connector. Install Spark Tester Jumper Wire (J 36012-A) into spark plug boot assemblies. Install Spark Tester (J 26792) on spark plug jumper wire for cylinder No. 1. Remove spark plug boot assembly from cylinder No. 4 of ignition coil housing. Install a jumper wire from cylinder No. 4 spark plug connector of ignition coil housing to ground. Connect a jumper wire to ICM assembly to ground. Crank engine. If spark is present at spark tester, go to step 7 . If spark is not present at spark tester, go to step 10 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 1 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 1 counter is not incrementing, go to step 25 .
7. Turn ignition off. Remove spark plug from No. 1 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 1 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 1 counter is not incrementing, go to step 9 .
8. Check for leaking fuel injector. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injectors are okay, check for basic engine problem. Repair as necessary. After repairs, go to step 25 .
9. Turn ignition off. Replace spark plugs. After replacing spark plugs, go to step 25 .
10. Turn ignition off. Remove spark plug boot assembly from affected coil. Disconnect ICM 11-pin harness connector. Connect a DVOM between the secondary ignition coil terminals at coil housing. Resistance should be 4000-8000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 12 .
11. Remove coil housing. Disconnect coil harness connector from ICM. Reconnect ICM 11-pin harness connector. Connect a test light to battery positive. Probe test light to ignition coil No. 1-4 control terminal "C". Crank engine. If test light blinks, go to step 13 . If test light does not blink, go to step 14 .
12. Remove coil No.1-4 from coil housing. Recheck resistance between secondary terminals of No.1-4 ignition coil. Resistance should be 4000-8000 ohms. If resistance is as specified, go to step 15 . If resistance is not as specified, go to step 16 .
13. Remove ignition coils from coil housing. Disconnect ignition coil harness connector from ignition coils. Reconnect ignition coil harness connector from ignition coils. Connect a test light to ground. Turn ignition on, with engine off. Using test light, probe ignition feed circuit to ignition coils at both ignition coil harness connector terminals "B". If test light illuminates on both circuits, go to step 19 . If test light does not illuminate on both circuits, go to step 20 .
14. Turn ignition off. Disconnect and check ICM 11-pin harness connector. Ensure connector is clean and tight. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to step 17 .
15. Check ignition coil spring for cylinders No. 1 and 4 coils. Check coil housing. Repair or replace as necessary. After repairs or inspection, go to step 25 .
16. Replace cylinders No. 1 and 2 ignition coil. After replacing ignition coils, go to step 25 .
17. Reconnect ICM 11-pin harness connector. Disconnect PCM harness connector C1. Reconnect spark plug No. 1 boot assembly to No.1 spark plug connector at ignition coil housing. Reconnect spark plug spark plug jumper wire to No.1 spark plug wire. Connect a jumper wire to No. 4 spark plug connector at ignition coil housing ground. Turn ignition on, with engine off. Connect test light battery positive, the momentarily touch test light to IC input circuit at PCM harness connector. Spark should be present when test light is removed from IC input circuit. If spark is present, go to step 23 . If spark is not present, go to next step.
18. Turn ignition off. Check ignition control input circuit for open, short to ground or short to voltage. Check for faulty connection at ICM. Repair as necessary. After repairs, go to step 25 . If circuits and connections are okay, go to step 22 .
19. Check No. 1-4 coil control circuit for poor connection to ICM and ignition coil. Check circuit for open, shorted to ground or shorted to voltage. Repair as necessary. After repairs, go to step 25 . If circuit and connections are okay, go to step 21 .
20. Turn ignition off. Repair open in ignition feed circuit between No. 1-4 and No. 2-3 ignition coil connectors. After repairs, go to next step.
21. Turn ignition off. Check ignition feed circuit for poor connection at ignition coil No. 1-4. Repair as necessary. After repairs, go to step 25 . If connections are okay, replace spark plug boot assembly. After replacing spark plug boot, go to step 25 .
22. Turn ignition off. Replace ICM. After replacing ICM, go to step 25 .
23. Turn ignition off. Check PCM harness connectors. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to next step.
24. Replace PCM. Reprogram replacement PCM. After replacing PCM, go to next step.
25. Reconnect all previously disconnected components. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0301. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
26. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0302: CYLINDER NO. 2 MISFIRE DETECTED (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL) indicating that catalytic converter damage is possible. Conditions for setting this DTC

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 and P1621 not set.
2. Misfire total is greater than 12 counts.
3. Engine speed is 469-6406 RPM.
4. Battery voltage is 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. Engine run time greater than 15 seconds.
7. TP sensor angle has not changed more than 8 percent in one second.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 6 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 2 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 2 counter is not incrementing, go to step 6 .
5. Turn ignition off. Disconnect fuel injector harness connector. Install Spark Tester (J-26792) to cylinder No. 2 spark plug wire. Remove spark plug wire No. 3 from ignition coil. Connect a jumper wire between ground and ignition coil tower (where spark plug wire No. 3 was). Crank engine and check for spark. If spark is present, go to step 8 . If spark is not present, go to step 9 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 2 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 2 counter is not incrementing, go to next step.
7. If a repair was made after visual inspection was performed in step 3 , go to step 30 . If no problems were found in visual inspection, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Remove spark plug from No. 2 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 2 counter is incrementing properly, go to step 13 . If MISFIRE CURRENT NO. 2 counter is not incrementing properly, go to step 22 .
9. Remove spark plug wire from cylinder No. 2. Using DVOM, check spark plug wire resistance. If resistance is less than 3000 ohms, go to next step. If resistance is not less than 3000 ohms, go to step 23 .
10. Remove ignition coil from cylinder that did not have spark. Check secondary resistance of coil. If resistance is 5000-8000 ohms, go to next step. If resistance is not 5000-8000 ohms, go to step 24 .
11. Replace coil with a known-good coil. Crank engine and check for spark. If spark is present, go to step 24 . If spark is not present, go to next step.
12. Disconnect and inspect Ignition Control Module (ICM) 6-pin connector. Repair as necessary. After repairs, go to step 30 . If connector is okay, go to step 25 .
13. Turn ignition off. Disconnect all fuel injector connectors. Install injector test light on injector harness connector for cylinder No. 2. Crank engine and observe test light. If test light flashes, go to next step. If test light does not flash, go to step 15 .
14. Perform INJECTOR BALANCE TEST. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injector No. 2 is okay, go to step 28 . If injector No. 2 is not okay, go to step 29 .
15. Remove injector test light. Connect a test light between ground and ignition feed terminal at No. 2 injector harness connector. Crank engine and observe test light. If test light is on, go to next step. If test light is off, go to step 27 .
16. Turn ignition off. Disconnect PCM harness connectors. With test light connected to ground, probe injector driver circuit terminal at No. 2 injector harness connector. If test light is off, go to next step. If test light is on, go to step 26 .
17. With test light connected to positive battery terminal, probe injector driver circuit terminal at No. 2 injector harness connector. If test light is off, go to next step. If test light is on, go to step 19 .
18. Inspect PCM connectors for damaged pins, corrosion and loose wires. If connectors are okay, go to step 20 . If connectors are not okay, go to step 21 .
19. Repair short to ground in cylinder No. 2 fuel injector driver circuit. After repairs, go to step 30 .
20. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 30 .
21. Repair connector or connections as necessary. After repairs, go to step 30 .
22. Replace spark plug. After replacing spark plug, go to step 30 .
23. Replace spark plug wire. After replacing spark plug wire, go to step 30 .
24. Replace ignition coil. After replacing ignition coil, go to step 30 .
25. Replace ICM. After replacing module, go to step 30 .
26. Repair short to voltage in cylinder No. 2 fuel injector driver circuit. After repairs, go to step 30 .
27. Repair open in ignition feed circuit. After repairs, go to step 30 .
28. Check for a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 30 .
29. Replace defective fuel injector. After replacing injector, go to next step.
30. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0302. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
31. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0302: CYLINDER NO. 2 MISFIRE DETECTED (2.4L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting this DTC are as follows

1. Misfire total is greater than 8 counts.
2. Engine speed is 469-6400 RPM.
3. Battery voltage 9-17 volts.
4. ECT 20-254°F (-7 to 123°C).
5. Engine run time is longer than 5 seconds.
6. TP sensor angle has not changed more than 8 percent in one second.
7. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133 and P1621 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 25 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 2 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 2 counter is not incrementing, go to step 6 .
5. Turn ignition off. Remove air cleaner outlet resonator assembly. Disconnect all fuel injector harness connectors. Disconnect ICM 11-pin harness connector. Temporarily remove ignition coil and ICM assembly. Reconnect ICM 11-pin harness connector. Install Spark Tester Jumper Wire (J 36012-A) into spark plug boot assemblies. Install Spark Tester (J 26792) on spark plug jumper wire for cylinder No. 2. Remove spark plug boot assembly from cylinder No. 3 of ignition coil housing. Install a jumper wire from cylinder No. 3 spark plug connector of ignition coil housing to ground. Connect a jumper wire to ICM assembly to ground. Crank engine. If spark is present at spark tester, go to step 7 . If spark is not present at spark tester, go to step 10 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 2 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 2 counter is not incrementing, go to step 25 .
7. Turn ignition off. Remove spark plug from No. 2 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 1 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 2 counter is not incrementing, go to step 9 .
8. Check for leaking fuel injector. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injectors are okay, check for basic engine problem. Repair as necessary. After repairs, go to step 25 .
9. Turn ignition off. Replace spark plugs. After replacing spark plugs, go to step 25 .
10. Turn ignition off. Remove spark plug boot assembly from affected coil. Disconnect ICM 11-pin harness connector. Connect a DVOM between the secondary ignition coil terminals at coil housing. Resistance should be 4000-8000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 12 .
11. Remove coil housing. Disconnect coil harness connector from ICM. Reconnect ICM 11-pin harness connector. Connect a test light to battery positive. Probe test light to ignition coil No. 2-3 control terminal "C". Crank engine. If test light blinks, go to step 13 . If test light does not blink, go to step 14 .
12. Remove coil No.2-3 from coil housing. Recheck resistance between secondary terminals of ignition coil. Resistance should be 4000-8000 ohms. If resistance is as specified, go to step 15 . If resistance is not as specified, go to step 16 .
13. Remove ignition coils from coil housing. Disconnect ignition coil harness connector from ignition coils. Reconnect ignition coil harness connector from ignition coils. Connect a test light to ground. Turn ignition on, with engine off. Using test light, probe ignition feed circuit to ignition coils at both ignition coil harness connector terminals "B". If test light illuminates on both circuits, go to step 19 . If test light does not illuminate on both circuits, go to step 20 .
14. Turn ignition off. Disconnect and check ICM 11-pin harness connector. Ensure connector is clean and tight. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to step 17 .
15. Check ignition coil spring for cylinders No. 2 and 3 coils. Check coil housing. Repair or replace as necessary. After repairs or inspection, go to step 25 .
16. Replace cylinders No. 2 and 3 ignition coil. After replacing ignition coils, go to step 25 .
17. Reconnect ICM 11-pin harness connector. Disconnect PCM harness connector C1. Reconnect spark plug No. 2 boot assembly to No.2 spark plug connector at ignition coil housing. Reconnect spark plug spark plug jumper wire to No.2 spark plug wire. Connect a jumper wire to No. 3 spark plug connector at ignition coil housing ground. Turn ignition on, with engine off. Connect test light battery positive, the momentarily touch test light to IC input circuit at PCM harness connector C1. Spark should be present when test light is removed from IC input circuit. If spark is present, go to step 23 . If spark is not present, go to next step.
18. Turn ignition off. Check ignition control input circuit for open, short to ground or short to voltage. Check for faulty connection at ICM. Repair as necessary. After repairs, go to step 25 . If circuits and connections are okay, go to step 22 .
19. Check No. 2-3 coil control circuit for poor connection to ICM and ignition coil. Check circuit for open, shorted to ground or shorted to voltage. Repair as necessary. After repairs, go to step 25 . If circuit and connections are okay, go to step 21 .
20. Turn ignition off. Repair open in ignition feed circuit between No. 1-4 and No. 2-3 ignition coil connectors. After repairs, go to next step.
21. Turn ignition off. Check ignition feed circuit for poor connection at ignition coil No. 2-3. Repair as necessary. After repairs, go to step 25 . If connections are okay, replace spark plug boot assembly. After replacing spark plug boot, go to step 25 .
22. Turn ignition off. Replace ICM. After replacing ICM, go to step 25 .
23. Turn ignition off. Check PCM harness connectors. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to next step.
24. Replace PCM. Reprogram replacement PCM. After replacing PCM, go to next step.
25. Reconnect all previously disconnected components. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
26. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0303: CYLINDER NO. 3 MISFIRE DETECTED (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 and P1621 not set.
2. Misfire total is greater than 12 counts.
3. Engine speed is 469-6406 RPM.
4. Battery voltage 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. TP sensor angle has not changed more than 8 percent in one second.
7. Engine run time is more than 15 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 6 . If no problems are found, go to next step.
4. Start engine and allow to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 3 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 3 counter is not incrementing, go to step 6 .
5. Turn ignition off. Disconnect fuel injector harness connector. Install Spark Tester (J-26792) to cylinder No. 3 spark plug wire. Remove No. 2 spark plug wire from ignition coil. Connect a jumper wire between ground and ignition coil tower (where No. 2 spark plug wire was). Crank engine and check for spark. If spark is present, go to step 8 . If spark is not present, go to step 9 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 3 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 3 counter is not incrementing, go to next step.
7. If a repair was made after visual inspection was performed in step 3 , go to step 30 . If no problems were found in visual inspection, go to «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Remove spark plug from No. 3 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 3 counter is incrementing properly, go to step 13 . If MISFIRE CURRENT NO. 3 counter is not incrementing properly, go to step 22 .
9. Remove spark plug wire from No. 3 cylinder. Using DVOM, check plug wire resistance. If resistance is less than 3000 ohms, go to next step. If resistance is not less than 3000 ohms, go to step 23 .
10. Remove ignition coil from cylinder that did not have spark. Measure secondary resistance of coil. If resistance is 5000-8000 ohms, go to next step. If resistance is not 5000-8000 ohms, go to step 24 .
11. Replace coil with a known-good coil. Crank engine and check for spark. If spark is present, go to step 24 . If spark is not present, go to next step.
12. Disconnect and inspect Ignition Control Module (ICM) 6-pin connector. Repair as necessary. After repairs, go to step 30 . If connector is okay, go to step 25 .
13. Turn ignition off. Disconnect all fuel injector connectors. Install injector test light on injector harness connector for No. 3 cylinder. Crank engine and observe test light. If test light flashes, go to next step. If test light does not flash, go to step 15 .
14. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article. If No. 3 injector is okay, go to step 28 . If No. 3 injector is not okay, go to step 29 .
15. Remove injector test light. Connect a test light between ground and ignition feed terminal at No. 3 injector harness connector. Crank engine and observe test light. If test light is on, go to next step. If test light is off, go to step 27 .
16. Turn ignition off. Disconnect PCM harness connectors. With test light connected to ground, probe injector driver circuit terminal at No. 3 injector harness connector. If test light is off, go to next step. If test light is on, go to step 26 .
17. With test light connected to positive battery terminal, probe injector driver circuit terminal at No. 3 injector harness connector. If test light is off, go to next step. If test light is on, go to step 19 .
18. Inspect PCM connectors for damaged pins, corrosion and loose wires. If connectors are okay, go to step 20 . If connectors are not okay, go to step 21 .
19. Repair short to ground in cylinder No. 3 fuel injector driver circuit. After repairs, go to step 30 .
20. Replace PCM. Program replacement PCM using required equipment. After repairs, go to step 30 .
21. Repair connector or connections as necessary. After repairs, go to step 30 .
22. Replace spark plug. After replacing spark plug, go to step 30 .
23. Replace spark plug wire. After replacing spark plug wire, go to step 30 .
24. Replace ignition coil. After replacing ignition coil, go to step 30 .
25. Replace ICM. After replacing ICM, go to step 30 .
26. Repair short to voltage in cylinder No. 3 fuel injector driver circuit. After repairs, go to step 30 .
27. Repair open in ignition feed circuit. After repairs, go to step 30 .
28. Check for a basic engine problem (cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 30 .
29. Replace defective fuel injector. After repairs, go to next step.
30. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0303. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
31. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0303: CYLINDER NO. 3 MISFIRE DETECTED (2.4L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting this DTC are as follows

1. Misfire total is greater than 8 counts.
2. Engine speed is 469-6400 RPM.
3. Battery voltage 9-17 volts.
4. ECT 20-254°F (-7 to 123°C).
5. Engine run time is longer than 5 seconds.
6. TP sensor angle has not changed more than 8 percent in one second.
7. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133 and P1621 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 25 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 3 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 3 counter is not incrementing, go to step 6 .
5. Turn ignition off. Remove air cleaner outlet resonator assembly. Disconnect all fuel injector harness connectors. Disconnect ICM 11-pin harness connector. Temporarily remove ignition coil and ICM assembly. Reconnect ICM 11-pin harness connector. Install Spark Tester Jumper Wire (J 36012-A) into spark plug boot assemblies. Install Spark Tester (J 26792) on spark plug jumper wire for cylinder No. 3. Remove spark plug boot assembly from cylinder No. 2 of ignition coil housing. Install a jumper wire from cylinder No. 2 spark plug connector of ignition coil housing to ground. Connect a jumper wire to ICM assembly to ground. Crank engine. If spark is present at spark tester, go to step 7 . If spark is not present at spark tester, go to step 10 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 3 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 3 counter is not incrementing, go to step 15 .
7. Turn ignition off. Remove spark plug from No. 3 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 3 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 3 counter is not incrementing, go to step 9 .
8. Check for leaking fuel injector. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injectors are okay, check for basic engine problem. Repair as necessary. After repairs, go to step 25 .
9. Turn ignition off. Replace spark plugs. After replacing spark plugs, go to step 25 .
10. Turn ignition off. Remove spark plug boot assembly from affected coil. Disconnect ICM 11-pin harness connector. Connect a DVOM between the secondary ignition coil terminals at coil housing. Resistance should be 4000-8000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 12 .
11. Remove coil housing. Disconnect coil harness connector from ICM. Reconnect ICM 11-pin harness connector. Connect a test light to battery positive. Probe test light to ignition coil No. 2-3 control terminal "C". Crank engine. If test light blinks, go to step 13 . If test light does not blink, go to step 14 .
12. Remove No.2-3 coil from housing. Recheck resistance between secondary terminals of No.2-3 ignition coil. Resistance should be 4000-8000 ohms. If resistance is as specified, go to step 15 . If resistance is not as specified, go to step 16 .
13. Remove ignition coils from coil housing. Disconnect ignition coil harness connector from ignition coils. Reconnect ignition coil harness connector from ignition coils. Connect a test light to ground. Turn ignition on, with engine off. Using test light, probe ignition feed circuit to ignition coils at both ignition coil harness connector terminals "B". If test light illuminates on both circuits, go to step 19 . If test light does not illuminate on both circuits, go to step 20 .
14. Turn ignition off. Disconnect and check ICM 11-pin harness connector. Ensure connector is clean and tight. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to step 17 .
15. Check ignition coil spring for cylinders No. 2 and 3 coils. Check coil housing. Repair or replace as necessary. After repairs or inspection, go to step 25 .
16. Replace cylinders No. 2 and 3 ignition coil. After replacing ignition coils, go to step 25 .
17. Reconnect ICM 11-pin harness connector. Disconnect PCM harness connector C1. Reconnect spark plug No. 3 boot assembly to No.3 spark plug connector at ignition coil housing. Reconnect spark plug spark plug jumper wire to No. 3 spark plug wire. Connect a jumper wire to No. 2 spark plug connector at ignition coil housing ground. Turn ignition on, with engine off. Connect test light battery positive, the momentarily touch test light to IC input circuit at PCM harness connector C1. Spark should be present when test light is removed from IC input circuit. If spark is present, go to step 23 . If spark is not present, go to next step.
18. Turn ignition off. Check ignition control input circuit for open, short to ground or short to voltage. Check for faulty connection at ICM. Repair as necessary. After repairs, go to step 25 . If circuits and connections are okay, go to step 22 .
19. Check No. 2-3 coil control circuit for poor connection to ICM and ignition coil. Check circuit for open, shorted to ground or shorted to voltage. Repair as necessary. After repairs, go to step 25 . If circuit and connections are okay, go to step 21 .
20. Turn ignition off. Repair open in ignition feed circuit between No. 1-4 and No. 2-3 ignition coil connectors. After repairs, go to next step.
21. Turn ignition off. Check ignition feed circuit for poor connection at ignition coil No. 2-3. Repair as necessary. After repairs, go to step 25 . If connections are okay, replace spark plug boot assembly. After replacing spark plug boot, go to step 25 .
22. Turn ignition off. Replace ICM. After replacing ICM, go to step 25 .
23. Turn ignition off. Check PCM harness connectors. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to next step.
24. Replace PCM. Reprogram replacement PCM. After replacing PCM, go to next step.
25. Reconnect all previously disconnected components. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
26. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0304: CYLINDER NO. 4 MISFIRE DETECTED (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting DTC

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 and P1621 not set.
2. Misfire total is greater than 12 counts.
3. Engine speed is 469-6406 RPM.
4. Battery voltage 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. TP sensor angle has not changed more than 8 percent in one second.
7. Engine run time is more than 15 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 6 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 4 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 4 counter is not incrementing, go to step 6 .
5. Turn ignition off. Disconnect fuel injector harness connector. Install Spark Tester (J-26792) to cylinder No. 4 spark plug wire. Remove No. 1 spark plug wire from ignition coil. Connect a jumper wire between ground and ignition coil tower (where No. 1 spark plug wire was). Crank engine and check for spark. If spark is present, go to step 8 . If spark is not present, go to step 9 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 4 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 4 counter is not incrementing, go to next step.
7. If a repair was made after visual inspection was performed in step 3 , go to step 30 . If no problems were found in visual inspection, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
8. Remove spark plug from No. 4 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 4 counter is incrementing properly, go to step 13 . If MISFIRE CURRENT NO. 4 counter is not incrementing properly, go to step 22 .
9. Remove spark plug wire from No. 4 cylinder. Using DVOM, measure plug wire resistance. If resistance is less than 3000 ohms, go to next step. If resistance is not less than 3000 ohms, go to step 23 .
10. Remove ignition coil from cylinder that did not have spark. Measure secondary resistance of coil. If resistance is 5000-8000 ohms, go to next step. If resistance is not 5000-8000 ohms, go to step 24 .
11. Replace coil with a known-good coil. Crank engine and check for spark. If spark is present, go to step 24 . If spark is not present, go to next step.
12. Disconnect and inspect Ignition Control Module (ICM) 6-pin connector. Repair as necessary. After repairs, go to step 30 . If connector is okay, go to step 25 .
13. Turn ignition off. Disconnect all fuel injector connectors. Install injector test light on injector harness connector for No. 4 cylinder. Crank engine and observe test light. If test light flashes, go to next step. If test light does not flash, go to step 15 .
14. Perform injector balance test. See appropriate SYSTEM & COMPONENT TESTING article. If injector No. 4 is okay, go to step 28 . If injector No. 4 is not okay, go to step 29 .
15. Remove injector test light. Connect a test light between ground and ignition feed terminal at injector No. 4 harness connector. Crank engine and observe test light. If test light is on, go to next step. If test light is off, go to step 27 .
16. Turn ignition off. Disconnect PCM harness connectors. With test light connected to ground, probe injector driver circuit terminal at No. 4 injector harness connector. If test light is off, go to next step. If test light is on, go to step 26 .
17. With test light connected to positive battery terminal, probe injector driver circuit terminal at No. 4 injector harness connector. If test light is off, go to next step. If test light is on, go to step 19 .
18. Inspect PCM connectors for damaged pins, corrosion and loose wires. If connectors are okay, go to step 20 . If connectors are not okay, go to step 21 .
19. Repair short to ground in cylinder No. 4 fuel injector driver circuit. After repairs, go to step 30 .
20. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 30 .
21. Repair connector or connections as necessary. After repairs, go to step 30 .
22. Replace spark plug. After replacing spark plug, go to step 30 .
23. Replace spark plug wire. After replacing spark plug wire, go to step 30 .
24. Replace ignition coil. After replacing ignition coil, go to step 30 .
25. Replace ICM. After replacing ICM, go to step 30 .
26. Repair short to voltage in cylinder No. 4 fuel injector driver circuit. After repairs, go to step 30 .
27. Repair open in ignition feed circuit. After repairs, go to step 30 .
28. Check for a basic engine problem (cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 30 .
29. Replace defective fuel injector. After repairs, go to next step.
30. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0304. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
31. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0304: CYLINDER NO. 4 MISFIRE DETECTED (2.4L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors Crankshaft Position (CKP) sensor and Camshaft Position (CMP) sensor to detect if engine is misfiring. PCM looks for a sudden drop in crankshaft speed. This test is executed in blocks of 100 camshaft revolution tests. It may take several tests to set a DTC. Under light misfire conditions, it may take more than one trip to set a DTC. Severe misfire will flash Malfunction Indicator Light (MIL), indicating that catalytic converter damage is possible. Conditions for setting this DTC are as follows

1. Misfire total is greater than 8 counts.
2. Engine speed is 469-6400 RPM.
3. Battery voltage 9-17 volts.
4. ECT 20-254°F (-7 to 123°C).
5. Engine run time is longer than 5 seconds.
6. TP sensor angle has not changed more than 8 percent in one second.
7. DTCs P0105, P0107, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0171, P0172, P0325, P0335, P0341, P0342, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133 and P1621 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Perform a visual inspection of the following. Check vacuum hoses for splits, kinks and proper routing. Check for leaks at throttle body, intake manifold, EGR valve and PCV system. Check PCM grounds for proper connection. Check injector harness connectors for proper installation. Repair as necessary. After repairs, go to step 25 . If no problems are found, go to next step.
4. Start engine and allow it to idle. Using scan tool, select MISFIRE DATA LIST function and monitor MISFIRE CUR. COUNTERS (one counter per cylinder). If MISFIRE CURRENT NO. 4 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 4 counter is not incrementing, go to step 6 .
5. Turn ignition off. Remove air cleaner outlet resonator assembly. Disconnect all fuel injector harness connectors. Disconnect ICM 11-pin harness connector. Temporarily remove ignition coil and ICM assembly. Reconnect ICM 11-pin harness connector. Install Spark Tester Jumper Wire (J 36012-A) into spark plug boot assemblies. Install Spark Tester (J 26792) on spark plug jumper wire for cylinder No. 4. Remove spark plug boot assembly from cylinder No. 1 of ignition coil housing. Install a jumper wire from cylinder No. 1 spark plug connector of ignition coil housing to ground. Connect a jumper wire to ICM assembly to ground. Crank engine. If spark is present at spark tester, go to step 7 . If spark is not present at spark tester, go to step 10 .
6. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MISFIRE CURRENT NO. 4 counter is incrementing, go to step 5 . If MISFIRE CURRENT NO. 1 counter is not incrementing, go to step 15 .
7. Turn ignition off. Remove spark plug from No. 4 cylinder. Replace spark plug with a known-good spark plug. Reconnect fuel injection harness connector. Operate vehicle within misfire conditions as recorded in FREEZE FRAME. If MISFIRE CURRENT NO. 4 counter is incrementing, go to next step. If MISFIRE CURRENT NO. 4 counter is not incrementing, go to step 9 .
8. Check for leaking fuel injector. See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injectors are okay, check for basic engine problem. Repair as necessary. After repairs, go to step 25 .
9. Turn ignition off. Replace spark plugs. After replacing spark plugs, go to step 25 .
10. Turn ignition off. Remove spark plug boot assembly from affected coil. Disconnect ICM 11-pin harness connector. Connect a DVOM between the secondary ignition coil terminals at coil housing. Resistance should be 4000-8000 ohms. If resistance is as specified, go to next step. If resistance is not as specified, go to step 12 .
11. Remove coil housing. Disconnect coil harness connector from ICM. Reconnect ICM 11-pin harness connector. Connect a test light to battery positive. Probe test light to ignition coil No. 1-4 control terminal "C". Crank engine. If test light blinks, go to step 13 . If test light does not blink, go to step 14 .
12. Remove coil No.1-4 from coil housing. Recheck resistance between secondary terminals of No.1-4 ignition coil. Resistance should be 4000-8000 ohms. If resistance is as specified, go to step 15 . If resistance is not as specified, go to step 16 .
13. Remove ignition coils from coil housing. Disconnect ignition coil harness connector from ignition coils. Reconnect ignition coil harness connector from ignition coils. Connect a test light to ground. Turn ignition on, with engine off. Using test light, probe ignition feed circuit to ignition coils at both ignition coil harness connector terminals "B". If test light illuminates on both circuits, go to step 19 . If test light does not illuminate on both circuits, go to step 20 .
14. Turn ignition off. Disconnect and check ICM 11-pin harness connector. Ensure connector is clean and tight. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to step 17 .
15. Check ignition coil spring for cylinders No. 1 and 4 coils. Check coil housing. Repair or replace as necessary. After repairs or inspection, go to step 25 .
16. Replace cylinders No. 1 and 4 ignition coil. After replacing ignition coils, go to step 25 .
17. Reconnect ICM 11-pin harness connector. Disconnect PCM harness connector C1. Reconnect spark plug No. 4 boot assembly to No.4 spark plug connector at ignition coil housing. Reconnect spark plug spark plug jumper wire to No. 4 spark plug wire. Connect a jumper wire to No. 1 spark plug connector at ignition coil housing ground. Turn ignition on, with engine off. Connect test light battery positive, the momentarily touch test light to IC input circuit at PCM harness connector C1. Spark should be present when test light is removed from IC input circuit. If spark is present, go to step 23 . If spark is not present, go to next step.
18. Turn ignition off. Check ignition control input circuit for open, short to ground or short to voltage. Check for faulty connection at ICM. Repair as necessary. After repairs, go to step 25 . If circuits and connections are okay, go to step 22 .
19. Check No. 1-4 coil control circuit for poor connection to ICM and ignition coil. Check circuit for open, shorted to ground or shorted to voltage. Repair as necessary. After repairs, go to step 25 . If circuit and connections are okay, go to step 21 .
20. Turn ignition off. Repair open in ignition feed circuit between No. 1-4 and No. 2-3 ignition coil connectors. After repairs, go to next step.
21. Turn ignition off. Check ignition feed circuit for poor connection at ignition coil No. 1-4. Repair as necessary. After repairs, go to step 25 . If connections are okay, replace spark plug boot assembly. After replacing spark plug boot, go to step 25 .
22. Turn ignition off. Replace ICM. After replacing ICM, go to step 25 .
23. Turn ignition off. Check PCM harness connectors. Repair as necessary. After repairs, go to step 25 . If connectors are okay, go to next step.
24. Replace PCM. Reprogram replacement PCM. After replacing PCM, go to next step.
25. Reconnect all previously disconnected components. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
26. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. If reluctor wheel is okay, see appropriate TROUBLE SHOOTING - NO CODES article for intermittent diagnosis.

DTC P0325: KNOCK SENSOR CIRCUIT

Note. For circuit reference, See WIRING DIAGRAMS article.

Knock Sensor (KS) is used to detect engine detonation. PCM will retard spark timing based on signals from KS module. The KS produces an AC signal voltage that is sent to the KS module. The amount of AC voltage produced is proportional to the amount of knock. Conditions for setting this DTC are as follows

1. Engine run time is greater than 20 seconds.
2. ECT is greater than 131°F (56°C).
3. KS instantaneous voltage is less than one volt.
4. Engine speed is greater than 2200 RPM.
5. MAP is greater than 60 kPa.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start engine. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Operate engine at 10 percent throttle angle. Check Malfunction Indicator Light (MIL). If MIL is on, go to step 4 . If MIL is off, go to next step.
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If MIL is on, go to next step. If MIL is off, go to step 12 .
4. While listening to engine, increase and decrease engine RPM. If an audible noise or knock is present, go to next step. If no audible noise or knock is present, go to step 6 .
5. Repair cause of engine noise or knock. After repairs, go to step 12 .
6. Turn ignition off. Disconnect PCM harness connectors. Check resistance between ground and signal circuit terminal at PCM connector. If resistance is 90,000-110,000 ohms (95,000-105,000 ohms on 2.4L), go to next step. If resistance is not 90,000-110,000 ohms (95,000-105,000 ohms on 2.4L), go to step 9 .
7. Check KS signal circuit for poor connection at PCM. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
8. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 12 .
9. Check KS harness connector. Repair as necessary. After repairs, go to step 12 . If connector is okay, go to next step.
10. Check knock sensor circuit for open, short to ground or short to voltage. Repair as necessary. After repairs, go to step 12 . If circuits are okay, go to next step.
11. Replace KS. After replacing sensor, go to next step.
12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates that this DTC RAN AND PASSED, go to next step. If scan tool does not indicate that this DTC RAN AND PASSED, repeat step 2 .
13. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Check knock sensor for proper connection. A loose or over-torqued knock sensor can cause DTC to set.

DTC P0335: CRANKSHAFT POSITION (CKP) SENSOR CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) supplies battery power and ground to CKP sensor. CKP sensor sends a reference signal to PCM 7 times per revolution to indicate crankshaft position and engine speed. The seventh pulse is the sync pulse and is used for crankshaft position reference. PCM calculates when to pulse ignition coils based on these signals. Condition for setting this DTC is as follows

1. 7X resync counter is greater than 15 counts within 4 minutes and 15 seconds.
2. DTC P0341 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If engine will not start, go to NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If engine will start, go to next step.
3. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle for 5 minutes or until Malfunction Indicator Light (MIL) turns on. If MIL is on, go to next step. If MIL is off, go to step 5 .
4. With engine running, wiggle PCM connectors, CKP sensor connector and related wiring. If engine stumbles, go to step 6 . If engine does not stumble, go to step 7 .
5. Operate any non-engine related accessories on vehicle. If MED. RESOLUTION RESYNC CNTR on scan tool resyncs while operating accessories, go to step 9 . If MED. RESOLUTION RESYNC CNTR on scan tool does not resync while operating accessories, go to step 4 .
6. Repair poor connector connection, wiring or connector that caused engine to stumble. After repairs, go to step 13 .
7. If MIL turned on in step 3 , go to next step. If MIL did not turn on, go to step 13 .
8. Check wiring to PCM, ICM and CKP sensor for pinched or worn through wire insulation. Repair as necessary. After repairs, go to step 13 . If wiring is okay, go to step 10 .
9. Repair faulty circuit or accessory component that caused MED. RESOLUTION RESYNC CNTR on scan tool to resync. After repairs, go to step 13 .
10. Replace CKP sensor. Start engine and allow engine to idle for 5 minutes or until MIL turns on. If MIL turns on, go to next step. If MIL does not turn on, go to step 13 .
11. Replace PCM. Program replacement PCM using required equipment. Start engine and allow it to idle for 5 minutes or until MIL turns on. If MIL is on, go to next step. If MIL is off, go to step 13 .
12. Replace ICM. Start engine and allow it to idle for 5 minutes or until MIL turns on. If MIL is on, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If MIL is off, go to next step.
13. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0335. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 3 .
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

If complaint is engine cranks but will not run, DTC P0335 may be set if engine is cranked more than 15 times without turning ignition off between starting attempts.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. Intermittent can also be caused by a rubbed-through wire insulation or a poor connection.

DTC P0336: CRANKSHAFT POSITION (CKP) SENSOR PERFORMANCE (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Ignition Control Module (ICM) sends a reference signal to the Powertrain Control Module (PCM) 7 times per crankshaft revolution (7X reference) in order to indicate crankshaft position and RPM so PCM can determine when to pulse the ignition coils and control ignition timing. The ICM applies 5 volts through the 7X reference circuit to the PCM. PCM switches this circuit to ground for a very short period of time. The seventh pulse is the synch pulse and is used for crankshaft position reference. Condition for setting this DTC is as follows

1. 7X resync counter is greater than 15 counts within 4 minutes and 15 seconds.
2. Engine running.
3. DTC P0341 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If engine will not start, go to NO START DIAGNOSIS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If engine will start, go to next step.
3. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Operate vehicle within conditions for setting this DTC. Recheck DTCs. If DTC resets, go to next step. If DTC does not reset, go to step 5 .
4. Start and operate engine at idle. Wiggle connectors at PCM, ICM and CKP sensor. If engine stumbles, go to step 6 . If engine does not stumble, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
5. Operate any non-engine related accessories on vehicle. If MED. RESOLUTION RESYNC CNTR on scan tool resyncs while operating accessories, go to step 7 . If MED. RESOLUTION RESYNC CNTR on scan tool does not resync while operating accessories, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
6. Turn ignition off. Repair poor connector connection, wiring or connector that caused engine to stumble. After repairs, go to step 8 .
7. Repair faulty circuit or accessory component that caused MED. RESOLUTION RESYNC CNTR on scan tool to resync. After repairs, go to next step.
8. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 3 .
9. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

If complaint is engine cranks but will not run, this DTC may be set if engine is cranked more than 15 times without turning ignition off between starting attempts.

An intermittent can be caused by a defective CKP sensor reluctor wheel. Remove CKP sensor. Inspect reluctor wheel through CKP sensor mounting hole. Check porosity and condition of reluctor wheel. Intermittent can also be caused by a rubbed-through wire insulation or a poor connection.

DTC P0340: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT - LOW INPUT

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) uses CMP sensor signal to determine which cylinder is misfiring when a misfire is present. When PCM receives an intermittent signal from CMP sensor, the CMP ACTIVITY counter will increment. Conditions for setting this DTC are as follows

1. Engine is running.
2. CMP ACTIVITY counter does not increment.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start engine and allow it to idle. Install scan tool. If CMP ACTIVITY counter is incrementing, go to next step. If CMP ACTIVITY counter is not incrementing, go to step 4 .
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Check DTCs. If this DTC resets, go to next step. If this DTC does not reset, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
4. Disconnect CMP sensor connector. With test light connected to ground, probe CMP feed circuit terminal at CMP sensor harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 6 .
5. Connect to positive battery terminal. Probe test light to CMP ground circuit terminal at CMP sensor harness connector. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 8 .
6. Turn ignition off. Check for poor connection at CMP feed circuit at PCM connector. Repair as necessary. After repairs, go to step 18 . If connection is okay, go to step 15 .
7. Turn ignition off. Disconnect CMP harness connector. Install fused jumper wires between CMP harness connector and CMP sensor ground and ignition positive voltage connector terminals. Remove fuel pump fuse. Using a DVOM in HZ scale, connect DVOM between ground and CMP signal circuit at CMP sensor. Crank engine. If frequency reading is 0.5-2.6 Hz, go to step 9 . If frequency reading is not 0.5-2.6 Hz, go to step 14 .
8. Turn ignition off. Check for poor connection or open in CMP ground circuit. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 15 .
9. Turn ignition off. Disconnect PCM harness connector. Remove all jumpers from CMP sensor connectors. Turn ignition on, with engine off. Connect a test light to ground. Using test light, probe CMP sensor signal circuit at CMP harness connector. If test light illuminates, go to step 12 . If test light does not illuminate, go to next step.
10. Connect test light to battery voltage. Using test light, probe CMP sensor signal circuit at CMP harness connector. If test light illuminates, go to step 13 . If test light does not illuminate, go to next step.
11. Turn ignition off. Check CMP sensor signal circuit for open or poor connection. Repair as necessary. After repairs, go to step 18 . If circuit is okay, go to step 15 .
12. Turn ignition off. Repair short to voltage in CMP signal circuit. After repairs, go to step 18 .
13. Turn ignition off. Repair short to ground in CMP signal circuit. After repairs, go to step 18 .
14. Turn ignition off. Check for poor connection at CMP sensor. Repair as necessary. After repairs, go to step 18 . If connection is okay, go to step 16 .
15. Turn ignition off. Check for poor connection at PCM. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to step 17 .
16. Replace CMP sensor. After replacing sensor, go to step 18 .
17. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
18. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
19. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

DTC P0341: CAMSHAFT POSITION (CMP) SENSOR CIRCUIT PERFORMANCE

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) uses CMP sensor signal to determine which cylinder is misfiring when a misfire is present. When PCM receives an intermittent signal from CMP sensor, the CMP RESYNC counter will increment. Conditions for setting this DTC are as follows

1. Engine is running.
2. CMP RESYNC counter is greater than 15 counts in less than 256 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start and allow engine to idle. Install scan tool. If CMP RESYNC counter is incrementing, go to next step. If CMP RESYNC counter is not incrementing, go to step 4 .
3. Turn ignition off. Disconnect CMP sensor connector. Turn ignition on. If CMP RESYNC counter is incrementing, go to step 5 . If CMP RESYNC counter is not incrementing, go to step 6 .
4. With engine running, carefully wiggle CMP sensor connector. If CMP RESYNC counter is incrementing, go to next step. If CMP RESYNC counter is not incrementing, go to step 9 .
5. Check for poor connection at CMP sensor connector. Repair as necessary. After repairs, go to step 10 . If connector is okay, go to step 7 .
6. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 10 .
7. Turn ignition off. Disconnect PCM harness connector. Check CMP terminal at PCM harness connector for poor connection. Repair as necessary. After repairs, go to step 10 . If connections are okay, go to next step.
8. Replace CMP sensor. After replacing sensor, go to step 10 .
9. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. If CMP RESYNC counter is incrementing, go to step 3 . If CMP RESYNC counter is not incrementing, go to next step.
10. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0341. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
11. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Whenever PCM sees less than 15 resyncs in 256 seconds, counter is reset to zero. If a poor CMP sensor connection is present, CAM SENSOR REFERENCE ACTIVITY counter will stop incrementing and CAM SENSOR RESYNC counter will start incrementing.

DTC P0420: TWC SYSTEM - LOW EFFICIENCY

Note. For circuit reference, See WIRING DIAGRAMS article.

A three-way catalytic converter is used to maintain low emissions. The PCM monitors exhaust gasses from converter using Heated Oxygen Sensor (HO2S). HO2S is located in exhaust stream past the three-way catalytic converter. HO2S produces an output signal which indicates the oxygen capacity of the catalyst. This determines the catalyst's ability to convert exhaust emissions effectively.

During normal operation, HO2S signal will be less active than that produced by the front Oxygen Sensor (O2S). Powertrain Control Module (PCM) monitors catalyst efficiency in 2 stages. If catalyst efficiency falls to less than 75 percent, PCM will set a stage one fail flag, but will not illuminate Malfunction Indicator Light (MIL). If catalyst efficiency falls to less than 50 percent, PCM will set a stage 2 fail flag and MIL will be illuminated.

Conditions for setting this DTC are

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
2. Ignition voltage greater than 11.7 volts.
3. PCM sees less than 0.11 volt from EGR sensor.
4. Malfunction present for 25 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If any other DTCs are set, diagnose DTCs as necessary before proceeding. If no other DTCs are set, go to next step.
3. Check for exhaust system leak, especially near HO2S. Ensure HO2S connectors are secured and not touching exhaust. If a problem is found, go to next step. If no problem is found, go to step 5 .
4. Repair exhaust system as necessary. After repairs, go to step 6 .
5. Replace catalytic converter. After repairs, go to next step.
6. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0420. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
7. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

DTC P0440: EVAP SYSTEM

Note. For circuit reference, See WIRING DIAGRAMS article.

Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. Whenever a sufficient vacuum level cannot be achieved, a large leak or faulty EVAP purge solenoid is indicated.

Conditions for setting this DTC are as follows

1. BARO greater than 75 kPa.
2. IAT and ECT are 41-84°F (5-29°C).
3. IAT is not greater than 2°F (1°C), greater than ECT at start-up.
4. ECT is not greater than 12°F (7°C), greater than IAT at start-up.
5. Fuel tank level is 26-74 percent.
6. EVAP solenoid is enabled.
7. EVAP system is unable to achieve or maintain vacuum during diagnostic test. Amount of vacuum decay will vary with fuel level.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If DTC P0452, P0453 or P0460 is also set, go to that DTC first. If not, go to next step.
3. Check fuel cap for missing or loose condition. Repair or replace as necessary. After repairs, go to step 19 . If repair is not necessary, go to next step.
4. Turn ignition on, with engine off. Using scan tool, command EVAP canister purge valve and EVAP vent solenoid on and off. If purge valve and vent solenoid clicks, go to next step. If purge valve and/or vent solenoid does not click, diagnose PCM.
5. Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on, engine off. Using scan tool, observe fuel tank pressure sensor value. If scan tool reads zero mm Hg, go to step 7 . If scan tool does not read zero mm Hg, go to next step.
6. Check if EVAP purge line from fuel tank to EVAP canister is pinched, kinked or plugged. Repair or replace as necessary. After repairs, go to step 20 . If purge line is okay, diagnose system using DTC P0452 or P0453 tests.
7. Reconnect all EVAP hoses that was disconnected. Using scan tool, command EVAP vent solenoid on (closed). Connect the EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Attempt to pressurize EVAP system to 5 in. H2O while holding EVAP Pressure/Purge Diagnostic Station in HOLD position. If specified pressure is obtained, go to next step. If specified pressure cannot be obtained, go to step 10 .
8. Maintain EVAP system pressure at 5 in. H2O. Using scan tool, observe FUEL TANK VACUUM PRESSURE. If pressure reading is 3-7 in. H2O, go to step 12 . If pressure reading is not 3-7 in. H2O, go to next step.
9. Turn ignition off. Install Fuel Tank Cap Adapter (J-41415-40). Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to fuel tank cap adaptor. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on. Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Monitor pressure for 2 minutes. If pressure drops to less than 10 in. H2O, go to next step. If pressure does not drop to less than 10 in. H2O, go to step 14 .
10. Disconnect fuel tank vapor and EVAP purge hoses from EVAP canister. Plug canister fitting for fuel tank vapor hose. Ensure EVAP vent solenoid is still commanded on. Connect a hand-held vacuum pump to EVAP purge hose fitting on EVAP canister and apply 5 in. Hg. If vacuum holds, go to step 15 . If vacuum does not hold, go to step 14 .
11. Check for restricted fuel tank vapor and EVAP purge hoses. Repair as necessary. After repair is completed, go to step 20 . If hoses are okay, diagnose fuel tank pressure sensor using DTC P0452 or P0453 tests.
12. Disconnect vacuum hose at EVAP canister purge valve (from throttle body). Connect a hand-held vacuum pump to EVAP canister purge valve vacuum source fitting. Apply 10 in. Hg. Using scan tool, command EVAP canister purge valve on. If vacuum does not hold, go to next step. If vacuum holds, go to step 17 .
13. Connect a vacuum gauge to EVAP canister purge valve vacuum hose (from throttle body). Start engine. Increase engine speed to 2500 RPM. If vacuum is greater than 10 in. Hg, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If vacuum is 15 in. Hg or less, go to step 18 .
14. Check for disconnected or damaged vent hose. Also, check for damaged EVAP canister. Repair as necessary. After repair is completed, go to step 20 . If no problem is found, go to step 19 .
15. Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor hose or disconnected or damaged EVAP purge hose. Repair as necessary. After repairs, go to step 20 . If no problem is found, go to next step.
16. Using scan tool, command EVAP vent solenoid on. With EVAP pressure/purge diagnostic station connected to EVAP service port, attempt to pressurize EVAP system by leaving control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J-41416), locate and repair EVAP system leak. It may be necessary to partially lower fuel tank to examine hose connections at top of tank. After repair is completed, go to step 20 .
17. Replace EVAP canister purge valve. After replacing purge valve, go to step 20 .
18. Locate and repair cause of low or no vacuum. After repairs, go to step 20 .
19. Replace EVAP vent solenoid. After replacing solenoid, go to next step.
20. Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 15 in. H2O. Set rotary switch on diagnostic station to HOLD and observe EVAP pressure gauge. If pressure decreases to less than 10 in. H2O within 2 minutes, repeat step 3 . If pressure does not decrease to less than 10 in. H2O within 2 minutes, go to next step.
21. Clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that the diagnostic ran and passed, go to next step. If scan tool does not indicate that the diagnostic ran and passed, repeat step 2 .
22. Using scan tool, check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check for the following

1. Cranked and punctured EVAP canister.
2. Damaged or disconnected source vacuum line, EVAP purge line, vent hose, for fuel tank vapor line.
3. Poor connection at PCM.
4. Inspect harness connectors for backed-out terminals, improper mating, broken lock, damaged terminals, or poor wire connection.
5. Check for intermittent in circuit.
6. Check for kinked, pinched or plugged vacuum lines to EVAP purge or fuel tank vapor line. Also check for restrictions.
7. Faulty or damaged evaporative canister.

DTC P0442: EVAP CONTROL SYSTEM - SMALL LEAK DETECTED

Note. For circuit reference, See WIRING DIAGRAMS article.

Evaporative leak detection strategy is based on applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. After desired vacuum level has been achieved, EVAP purge solenoid is turned off, sealing the system. If a small leak is detected, a DTC P0442 will set.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133 not set.
2. BARO is greater than 75 kPa.
3. ECT and IAT is 41-84°F (5-29°C) at engine start-up.
4. IAT not greater than 2°F (1°C) of ECT at engine start-up.
5. ECT not greater than 12°F (7°C) of IAT at engine start-up.
6. Fuel tank level is 26-74 percent.
7. TP angle is 9-35 percent.
8. EVAP solenoid is enabled.
9. EVAP system is unable to achieve or maintain vacuum during diagnostic test. Amount of vacuum decay will vary with fuel level.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If DTC P0452, P0453 or P0460 is also set, go to that DTC first. If these DTCs are not set, go to next step.
3. Turn ignition on, with engine off. Using scan tool, command EVAP canister purge and vent valve solenoids on and off. If purge and vent solenoids click on and off, go to next step. If purge and/or vent solenoid does not click, perform PCM diagnosis. See appropriate SYSTEM & COMPONENT TESTING article.
4. Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on, engine off. Using scan tool, check fuel tank pressure sensor value. If fuel tank pressure is zero mm Hg, go to step 6 . If fuel tank pressure is not zero mm Hg, go to next step.
5. Check EVAP purge line from fuel tank to EVAP canister for pinched, kinked or plugged line. Repair as necessary. After repairs, go to step 14 . If line is okay, diagnose using DTC P0452 or P0453 diagnostic tests.
6. Reconnect all disconnected EVAP hardware. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using scan tool, command EVAP vent valve on (closed). Pressurize EVAP system to 12 mm Hg using EVAP pressure/purge diagnostic station and place switch in HOLD position. Observe fuel tank pressure on scan tool. If fuel tank pressure is 10 mm Hg, go to next step. If fuel tank pressure is not 10 mm Hg, diagnose using DTC P0452 or P0453 diagnostic tests.
7. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Pressurize EVAP system to 15 in. H2O using EVAP Pressure/Purge Diagnostic Station (J-41413). Switch rotary switch to HOLD position and observe EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 9 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
8. Turn ignition off. Install Fuel Tank Cap Adapter (J-41415-40). Turn ignition on, engine off. Using scan tool, command EVAP SYSTEM SEAL on. Pressurize EVAP system to 15 in. H2O. Monitor pressure on EVAP pressure gauge. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 12 . If pressure does not drop to less than 10 in. H2O within 2 minutes, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
9. Disconnect fuel tank vapor line and EVAP purge line from EVAP canister. Block fuel tank vapor line fitting on canister. Connect a hand-held vacuum pump to EVAP purge line fitting on canister. Ensure EVAP vent solenoid is still commanded on (closed). Attempt to apply vacuum to canister. If 5 in. Hg can be maintained, go to step 12 . If 5 in. Hg cannot be maintained, go to next step.
10. Check for disconnected or damaged vent hose, or damaged EVAP canister. Repair or replace as necessary. After repairs, go to step 13 . If no problems were found, go to next step.
11. Replace EVAP vent solenoid. After replacing EVAP vent solenoid, go to step 13 .
12. Check for faulty fuel cap, leaking filler neck, leaking vapor or purge lines. Repair as necessary. Reconnect all EVAP hardware previously disconnected. Command EVAP vent solenoid on (closed) using scan tool. With EVAP Pressure/Purge Diagnostic Station (J-41413) connected to EVAP system, leave control knob in PRESSURIZED position. Using Ultrasonic Leak Detector (J-41416), locate and repair leak in EVAP system. Fuel tank might have to be partially lowered to be able to check tank connections. After repairs, go to next step.
13. Pressurize EVAP system to 15 in. H2O using EVAP purge/pressure diagnostic station. Set switch to HOLD position. If pressure drops to less than 10 in. H2O within 2 minutes, go to step 3 . If pressure does not drop to less than 10 in. H2O within 2 minutes, go to next step.
14. Using scan tool, select DTC, CLEAR INFO. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that the diagnostic ran and passed, go to next step. If scan tool does not indicate that the diagnostic ran and passed, repeat step 3 .
15. Check if additional DTCs are set. If additional DTCs are set, go to applicable DTC test. If no additional DTCs are set, system is okay.

Check for missing or damaged "O" rings at EVAP canister fuel vapor fittings and purge line fittings. Check for cracked EVAP canister. Check for damaged or disconnected vacuum source hose, EVAP purge hose, vent hose or fuel tank vapor hose. Check PCM connector for poor terminal connections. Check for damaged EVAP related wiring harness.

DTC P0446: EVAP VENT SYSTEM PERFORMANCE

Note. For circuit reference, See WIRING DIAGRAMS article.

The Evaporative Emission (EVAP) system includes the fuel tank, EVAP vent solenoid, fuel tank pressure sensor, fuel pipes and hoses, fuel vapor lines, fuel cap, EVAP canister, purge lines, EVAP canister purge solenoid valve and EVAP service port.

The EVAP system is checked by applying vacuum to the EVAP system and by monitoring vacuum decay. PCM monitors the vacuum level through the fuel tank pressure sensor signal. At an appropriate time, the EVAP canister purge solenoid valve and the EVAP vent solenoid are turned on, allowing engine to draw a small vacuum on the entire evaporative system. After the desired vacuum level has been achieved, the EVAP canister purge solenoid is tuned off, sealing the system. With EVAP vent solenoid open, any vacuum in system should decrease quickly unless vent path is blocked.

Conditions required to test for DTC are

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0452, P0453, P0502, P0503, P0601, P0602, P1621 and P1133 not set.
2. BARO is greater than 75 kPa.
3. ECT and IAT temperature 41-84°F (5-29°C) at engine start-up.
4. IAT is not greater than 2°F (1°C) of ECT at engine start-up.
5. ECT is not greater than 12°F (7°C) of IAT at engine start-up.
6. Fuel tank level is 26-74 percent.
7. TP angle is 7-35 percent.
8. EVAP system is unable to achieve or maintain vacuum during diagnostic test. The amount of decay will vary with fuel level.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Check for DTCs. If DTC P0452, P0453 or P0461 is also set, diagnose affected DTC first. If these DTCs are not set, go to next step.
3. Turn ignition on, with engine off. Using scan tool, command EVAP canister purge and vent valve solenoids on and off. If purge and vent solenoids click on and off when commanded, go to next step. If purge and/or vent solenoid does not click, perform PCM diagnosis. See appropriate SYSTEM & COMPONENT TESTING article.
4. Turn ignition off. Disconnect vapor line from fuel tank at EVAP canister. Turn ignition on, with engine off. Using scan tool, check fuel tank pressure sensor value. If fuel tank pressure is zero mm Hg, go to step 6 . If fuel tank pressure is not zero mm Hg, go to next step.
5. Turn ignition off. Check EVAP vapor line from fuel tank to EVAP canister for pinched, kinked or plugged line. Repair or replace as necessary. After repairs, go to step 12 . If line is okay, diagnose using DTC P0452 or P0453 diagnostic tests. See «DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT - LOW VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0452-fuel-tank-pressure-sensor) or «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0453-fuel-tank-pressure-sensor) .
6. Reconnect all disconnected EVAP hardware. Connect EVAP Pressure/Purge Diagnostic Station (J-41413) to EVAP service port. Using scan tool, command EVAP vent valve on (closed). Pressurize EVAP system to 5 in. H2O using diagnostic station. Observe fuel tank pressure on scan tool. If fuel tank pressure is 12 mm Hg, go to next step. If fuel tank pressure is not 12 mm Hg, diagnose using DTC P0452 or P0453 tests. See «DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT - LOW VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0452-fuel-tank-pressure-sensor) or «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0453-fuel-tank-pressure-sensor)
7. Maintain EVAP pressure at 5 in. H2O. Command EVAP vent solenoid off (open) while observing EVAP pressure gauge. If EVAP pressure return line is zero in. H2O within 5 seconds, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If EVAP pressure return line is not zero in. H2O within 5 seconds, go to next step.
8. Disconnect large vent hose from EVAP canister marked AIR. Switch rotary switch on diagnostic station to PURGE position. Start and warm engine to normal operating temperature. Observe vacuum gauge for 5 seconds while holding engine speed to 2500 RPM. If vacuum reading remains less than 10 in. H2O, go to next step. If vacuum reading does not remain less than 10 in. Hg, go to step 11 .
9. Turn ignition off. Check for kinked, pinched or blocked EVAP vent hose between EVAP canister and EVAP vent solenoid. Repair as necessary. After repairs, go to step 12 . If hose is okay, go to next step.
10. Replace EVAP vent solenoid. After replacing solenoid, go to step 12 .
11. Replace EVAP canister. After replacing canister, go to next step.
12. Reconnect all disconnected EVAP hardware. Turn ignition on, with engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge diagnostic station, pressurize EVAP system to 5 in. H2O. Set rotary switch on pressure/purge diagnostic station to HOLD position. Observe EVAP pressure gauge. If pressure decreases to zero in. H2O within 5 seconds, go to next step. If pressure does not decrease to zero in. H2O within 5 seconds, repeat step 3 .
13. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 3 .
14. Using scan tool, check for additional undiagnosed DTCs. If additional DTCs are set, diagnose applicable DTCs. If no additional DTCs are set, system is okay.

Check for kinked, pinched or plugged vent hose between EVAP canister and EVAP vent solenoid. Check PCM connector for poor terminal connections. Check for damaged EVAP related wiring harness.

DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage of 0.2-4.0 volts. If PCM detects a fuel tank pressure sensor signal that is excessively low, DTC will set.

Conditions for setting DTC

1. Ignition on.
2. Fuel tank pressure sensor signal is less than 0.1 volt for greater than 25 seconds.
3. Conditions present for one second.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is 0.20 volt or greater, go to next step. If scan tool reading is not 0.20 volt or greater, go to step 4 .
3. Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. If fuel tank pressure is greater than 0.20 volt, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If fuel tank pressure is not greater than 0.20 volt, go to next step.
4. Turn ignition off. Disconnect fuel tank pressure sensor connector. Turn ignition on, engine off. Check voltage between 5-volt reference voltage circuit and sensor ground circuit at fuel tank pressure sensor harness connector. If voltage reading is 5 volts, go to step 7 . If voltage reading is not 5 volts, go to next step.
5. Check 5-volt reference circuit for poor terminal connection at PCM connector. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
6. Check fuel tank pressure sensor 5-volt reference circuit between fuel tank pressure sensor and PCM for open, short to ground, or short to sensor ground circuit. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
7. Turn ignition off. Remove fuel filler cap. Using appropriate test adapter from Connector Test Adapter Kit (J-35616-A), connect jumper between terminal "A" of fuel pressure sensor and terminal "A" of harness connector. Jumper fuel pressure sensor terminal "C" to harness connector terminal "C". Turn ignition on, engine off. Check voltage between ground and fuel tank pressure sensor terminal "B". If voltage reading is 1.3-1.7 volts, go to next step. If voltage reading is not 1.3-1.7 volts, go to step 11 .
8. Check for poor terminal connections at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If connections are okay, go to next step.
9. Check fuel tank pressure signal circuit between sensor connector and PCM for open or short to ground. Repair as necessary. After repairs, go to step 13 . If connection is okay, go to next step.
10. Check for poor terminal connection at fuel tank pressure sensor connector. Repair as necessary. After repairs, go to step 13 . If circuit is okay, go to step 12 .
11. Replace fuel tank pressure sensor. After replacing sensor, go to step 13 .
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
13. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .

An intermittent open in the signal or 5-volt reference circuit or connectors will set DTC. Wiggle harnesses and connectors while monitoring tank pressure voltage. Review malfunction history data and attempt to reproduce the condition and fault.

DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM monitors fuel tank pressure sensor signal to detect vacuum decay and excess vacuum during the enhanced EVAP diagnostic. Fuel tank pressure sensor measures the difference between air pressure (or vacuum) in the tank and the outside air pressure. PCM applies 5-volt reference and ground to the sensor. Sensor will return a signal voltage of 0.2-4.0 volts. If PCM detects fuel tank pressure sensor voltage greater than 4.9 volts and for longer than 25 seconds, DTC will set.

Conditions for setting DTC

1. Ignition on.
2. Fuel tank pressure sensor signal is greater than 4.9 volt for greater than 25 seconds.
3. Conditions present for 5 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Monitor fuel tank pressure sensor voltage on scan tool. If scan tool reading is greater than 3.0 volts, go to next step. If scan tool reading is not greater 3.0 volts, go to step 4 .
3. Turn ignition off. Disconnect fuel tank pressure sensor harness connector. Turn ignition on, engine off. If scan tool shows 0.2 volt or less, go to step 5 . If scan tool reading is not 0.2 volt or less, go to step 6 .
4. Turn ignition on, engine off. Using scan tool, review FREEZE FRAME and/or FAILURE RECORDS data for this DTC and observe parameters. Turn ignition off for 15 seconds. Start and operate vehicle within conditions required for this DTC to run. If scan tool displays fuel tank pressure value at 3.0 volts or greater, go to next step. If fuel tank pressure value is not 3.0 volts or greater, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
5. Using a test light connected to battery voltage, probe fuel tank pressure sensor ground circuit terminal. If test light illuminates, go to step 7 . If test light does not illuminate, go to step 9 .
6. Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure signal circuit for short to voltage or short to 5-volt reference circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 10 .
7. Check voltage between ground and fuel tank pressure sensor 5-volt reference circuit. If voltage reading is 5 volts, go to step 11 . If voltage reading is not 5 volts, go to next step.
8. Turn ignition off. Disconnect PCM harness connector. Check fuel tank pressure sensor 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 10 .
9. Check for open or poor connection in fuel tank pressure sensor ground circuit. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to next step.
10. Check for poor connection at PCM harness connector. Repair or replace as necessary. After repairs, go to step 12 .
11. Check for poor terminal connections at fuel tank pressure sensor connector. Repair or replace as necessary. After repairs, go to next step.
12. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
13. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay.

Check for damaged harness or poor connection at PCM or fuel tank pressure sensor.

DTC P0461: FUEL LEVEL SENSOR CIRCUIT PERFORMANCE

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM uses fuel level input in order to calculate expected vapor pressure within the fuel system. Vapor pressure vary as fuel level changes. Vapor pressure is critical in determining if EVAP system is operating properly. PCM also uses fuel level to determine is fuel system is too high or too low to be able to accurately detect EVAP system faults.

DTC will set when fuel level input has not changed more than 1.6 percent in 120 miles.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for DTCs. If DTC P0462 or P0463 is set, diagnose affected DTC. If DTC P0462 or P0463 is not set, go to next step.
3. Turn ignition off. Disconnect fuel level sensor harness connector. Turn ignition on, with engine off. Using scan tool, verify fuel level data with scan tool. If scan tool indicates 100 percent, go to next step. If scan tool data does not indicate 100 percent, go to step 5 .
4. Connect a fused jumper between fuel level sensor connector ground and signal circuit terminals. If scan tool indicates zero percent, go to step 10 . If scan tool does not indicate zero percent, go to step 6 .
5. Inspect fuel level sensor circuit for short to ground. Repair as necessary. After repairs, go to step 12 . If circuit is okay, go to step 9 .
6. Connect a test light to battery positive. Using test light, probe fuel level sensor ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 8 .
7. Check fuel level sensor signal circuit for open circuit or poor connection. Repair as necessary. After repairs, go to step 12 . If circuit or connection is okay, go to step 9 .
8. Check fuel level sensor ground circuit for open circuit or poor connection. Repair as necessary. After repairs, go to step 12 . If circuit or connection is okay, go to next step.
9. Turn ignition off. Replace PCM. Program replacement PCM using required equipment. Perform CKP system variation learning procedure. After repairs, go to step 12 .
10. Check fuel level sensor circuit for high resistance or poor connection. Repair as necessary. After repairs, go to step 12 . If circuit or connector is okay, go to next step.
11. Turn ignition off. Replace fuel level sensor. After replacing sensor, go to next step.
12. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting the DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, go to step 2 .
13. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation.

DTC P0462: FUEL LEVEL SENSOR CIRCUIT - LOW VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM uses fuel level input in order to calculate expected vapor pressure within the fuel system. Vapor pressure vary as fuel level changes. Vapor pressure is critical in determining if EVAP system is operating properly. PCM also uses fuel level to determine is fuel system is too high or too low to be able to accurately detect EVAP system faults.

DTC will set when fuel level sensor is less than 3.5 percent for greater than 25 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, check fuel level sensor value. If fuel level sensor value is greater than 3.5 percent, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If fuel level sensor value is not greater than 3.5 percent, go to next step.
3. Disconnect fuel level sensor connector. If fuel level sensor value is now greater than 98 percent, go to step 5 . If fuel level sensor value is not greater than 98 percent, go to next step.
4. Check fuel level sensor signal circuit for short to ground. Repair as necessary. After repairs, go to step 7 . If circuit is okay, go to step 6 .
5. Replace fuel level sensor. After replacing sensor, go to step 7 .
6. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
7. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting the DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, repeat step 2 .
8. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

Intermittent can be caused by poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check connectors for backed-out terminals, improper mating, broken lock, damaged terminal or poor terminal to wire connection. If electrical interference is suspected, install additional ground wire from IPC to negative battery terminal.

DTC P0463: FUEL LEVEL SENSOR CIRCUIT - HIGH VOLTAGE

Note. For circuit reference, See WIRING DIAGRAMS article.

PCM uses fuel level input in order to calculate expected vapor pressure within the fuel system. Vapor pressure vary as fuel level changes. Vapor pressure is critical in determining if EVAP system is operating properly. PCM also uses fuel level to determine is fuel system is too high or too low to be able to accurately detect EVAP system faults.

DTC will set when fuel level sensor is greater than 98 percent for greater than 25 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, check fuel level sensor value. If fuel level sensor value is greater than 98 percent, go to next step. If fuel level sensor value is not greater than 98 percent, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
3. Disconnect fuel level sensor connector. If fuel level sensor value is now less than 3.5 percent, go to step 5 . If fuel level sensor value is not less than 3.5 percent, go to next step.
4. Jumper fuel level sensor signal circuit at sensor connector to chassis ground. If fuel level sensor value is now greater than 3.5 percent, go to next step. If sensor value is not greater than 3.5 percent, go to step 6 .
5. Check for poor connections at fuel level sensor. Repair as necessary. After repairs, go to step 11 . If connections are okay, go to step 9 .
6. Check for open in fuel level sensor ground circuit. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to step 8 .
7. Check for open in fuel level sensor signal circuit. Repair as necessary. After repairs, go to step 11 . If circuit is okay, go to next step.
8. Check for poor sensor ground or signal circuit connection at PCM harness connector. Repair as necessary. After repairs, go to step 11 . If circuit and connections are okay, go to step 10 .
9. Replace fuel level sensor. After replacing sensor, go to step 11 .
10. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
11. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting the DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, repeat step 2 .
12. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

Intermittent can be caused by poor connection, rubbed-through wire insulation, or a wire broken inside the insulation. Check connectors for backed-out terminals, improper mating, broken lock, damaged terminal or poor terminal to wire connection. If electrical interference is suspected, install additional ground wire from IPC to negative battery terminal.

DTC P0480: COOLING FAN RELAY NO. 1 CIRCUIT (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Body Control Module can request the cooling fans to turn on by sending a Class 2 message to the PCM. The PCM enables cooling fan relays No. 1 and 2 by providing a ground path. The left and right cooling fans are connected in series. When cooling fan No. 1 relay is energized the fans operate at low speed. When all the relays are energized, the fans will operate at high speed. PCM will also enable cooling fans when it detects certain DTCs

DTC will set when engine is running and battery voltage is greater than 9.5 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command fan control relay No. 1 on and off. If relay turns on and off as commanded, go to next step. If relay does not turn on and off as commanded, go to step 5 .
3. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Using a DVOM in 10-amp scale, check current between cooling fan relay No. 1 control circuit and ground at PCM harness connector for 2 minutes. If current draw is less than 0.75 amp, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If current draw is not less than 0.75 amp, go to next step.
4. Turn ignition off. Remove cooling fan relay No. 1. Check DVOM reading. If reading is infinite resistance, go to step 12 . If reading is not infinite resistance, go to step 10 .
5. Turn ignition off. Remove cooling fan relay No. 1. Connect a test light between relay connector battery feed and control terminals. Turn ignition on, with engine off. Using scan tool, command fan control relay No. 1 on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off with each command, go to next step.
6. Connect test light to ground. Using test light probe battery circuit in fan control relay No. 1 connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
7. Turn ignition off. Reinstall cooling fan relay No. 1. Disconnect PCM harness connector containing cooling fan relay No. 1 circuit. Turn ignition on, with engine off. Using a fused jumper wire connected to ground, probe jumper wire to cooling fan relay No. 1 control circuit at PCM harness connector. Probe and release several times. If relay turns on and off, go to step 9 . If relay does not turn on and off, go to step 10 .
8. Turn ignition off. Check for poor connections at fan relay No. 1 connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
9. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
10. Turn ignition off. Repair open, short to ground or short to voltage in cooling fan relay No. 1 control circuit. After repairs, go to step 14 .
11. Turn ignition off. Repair open or short to ground in cooling fan relay No. 1 battery feed circuit. After repairs, go to step 14 .
12. Replace cooling fan control relay No. 1. After replacing relay, go to step 14 .
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
14. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
15. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

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

If complaint is an overheating problem, determine if complaint is due to an actual boilover, temperature light, or if temperature gauge indicated overheating.

DTC P0480: COOLING FAN RELAY NO. 1 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The cooling fan is controlled by the Body Control Module (BCM). BCM sends a Class 2 message to PCM in order to enable the fans based on various inputs. Ignition voltage travels to all 3 cooling fan relays. PCM provides ground path to relays. When PCM detects that certain DTCs are set, PCM will enable cooling fans.

DTC will set when PCM detects that commanded state of driver and actual state of control circuit do not match.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command cooling fan relay on and off. If cooling fan relay No. 1 turns on and off, go to next step. If cooling fan relay No. 1 does not turn on and off, go to step 5 .
3. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using DVOM in 10-amp scale, check current from cooling fan relay No. 1 control circuit in PCM connector to ground for 2 minutes. If current draw is less than 0.75 amp, but not zero, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If current draw is not less than 0.75 amp, go to next step.
4. Turn ignition off. Disconnect cooling fan relay No. 1. Check resistance between ground and fan relay No. 1 control circuit at PCM harness connector. If resistance is infinite, go to step 12 . If resistance is not infinite, go to step 10 .
5. Turn ignition off. Disconnect cooling fan relay No. 1. Connect test light between relay No. 1 control terminal and battery feed terminal in relay harness connector. Turn ignition on. Using scan tool, command relay No. 1 on and off. If test light turns on and off with each command, go to step 8 . If test light does not turn on and off, go to next step.
6. Connect test light between ground and relay No. 1 battery feed circuit in harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11 .
7. Turn ignition off. Reconnect cooling fan relay No. 1 relay. Disconnect PCM harness connector. Turn ignition on. Using a fused jumper wire, connect jumper between ground and cooling fan relay No. 1 control circuit at PCM connector. If relay operates, go to step 9 . If relay does not operate, go to step 10 .
8. Check connections at cooling fan control relay No. 1. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 12 .
9. Check connections at PCM. Repair as necessary. After repairs, go to step 14 . If connections are okay, go to step 13 .
10. Repair relay No. 1 control circuit. After repairs, go to step 14 .
11. Repair relay No. 1 battery feed circuit. After repairs, go to step 14 .
12. Replace cooling fan relay No. 1. After replacing relay, go to step 14 .
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
14. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
15. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

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

DTC P0481: COOLING FAN RELAY NO. 2 CONTROL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The cooling fan is controlled by the Body Control Module (BCM). BCM sends a Class 2 message to PCM in order to enable the fans based on various inputs. Ignition voltage travels to all 3 cooling fan relays. PCM provides ground path to relays. When PCM detects that certain DTCs are set, PCM will enable cooling fans.

DTC will set when PCM detects that commanded state of driver and actual state of control circuit do not match.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command cooling fan relay on and off. If cooling fan relay No. 2 turns on and off, go to next step. If cooling fan relay No. 2 does not turn on and off, go to step 5 .
3. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using DVOM in 10-amp scale, check current from cooling fan relay No. 2 control circuit in PCM connector to ground for 2 minutes. If current draw is less than 0.75 amp, but not zero, go to step 8 . If current draw is not less than 0.75 amp, go to next step.
4. Turn ignition off. Disconnect cooling fan relay No. 2. Check resistance between ground and fan relay No. 2 control circuit at PCM harness connector. If resistance is infinite, go to step 16 . If resistance is not infinite, go to step 14 .
5. Turn ignition off. Disconnect cooling fan relay No. 2. Connect test light between relay No. 2 control terminal and battery feed terminal in relay harness connector. Turn ignition on. Using scan tool, command relay No. 2 on and off. If test light turns on and off with each command, go to step 12 . If test light does not turn on and off, go to next step.
6. Connect test light between ground and relay No. 2 battery feed circuit in harness connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 15 .
7. Turn ignition off. Reconnect cooling fan relay No. 2. Disconnect PCM harness connector. Turn ignition on. Using a fused jumper wire, connect jumper between ground and cooling fan relay No. 2 control circuit at PCM connector. If relay operates, go to step 13 . If relay does not operate, go to step 14 .
8. Disconnect cooling fan relay No. 2. Using a fused jumper wire, jumper relay No. 2 control circuit to PCM connector ground circuit. If mode control relay turn on, go to next step. If mode control relay does not turn on, go to step 10 .
9. Using DVOM in 10-amp scale, check current at mode control relay control circuit in PCM harness connector terminal for 2 minutes. If current draw is less than 0.75 amp, but not less than zero, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If current draw is not less than 0.75 amp, go to step 16 .
10. Turn ignition off. Disconnect mode control relay. Connect test light between mode relay coil terminal in harness connector. Turn ignition on. Connect a fused jumper wire from mode control relay control circuit to ground circuit in PCM harness connector. If test light illuminates, go to step 12 . If test light does not illuminate, go to next step.
11. Using test light connected to ground, probe battery feed circuit in mode control relay connector. If test light illuminates, go to step 14 . If test light does not illuminate, go to step 15 .
12. Check connections at affected relay. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to step 16 .
13. Check connections at PCM. Repair as necessary. After repairs, go to step 18 . If connections are okay, go to step 17 .
14. Repair faulty relay control circuit. After repairs, go to step 18 .
15. Repair faulty relay battery feed circuit. After repairs, go to step 18 .
16. Replace faulty relay. After replacing relay, go to step 18 .
17. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
18. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
19. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay.

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

DTC P0502: VEHICLE SPEED SENSOR (VSS) CIRCUIT - LOW INPUT

Note. For circuit reference, See WIRING DIAGRAMS article.

Vehicle Speed Sensor (VSS) is a permanent magnet generator that is mounted on transaxle. VSS produces a pulsing voltage whenever vehicle speed is greater than 3 MPH. A/C voltage and number of pulses increases with vehicle speed. Powertrain Control Module (PCM) then supplies VSS signal to instrument cluster for speedometer, odometer, electronic transaxle (if equipped) and cruise control operation.

Conditions for setting DTC

1. Vehicle speed is less than 2 MPH.
2. Engine speed is 1700-3600 RPM.
3. TP angle 0-1 percent.
4. Engine vacuum between 80-70 kPa.
5. Conditions met for 5 seconds.
6. DTCs P0107, P0108, P0122 and P0123 not set.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step. CAUTION: Support lower control arms so drive axles are in normal horizontal position or drive axles will be damaged.
2. Turn ignition off. Raise and support drive axles. Start engine. With engine at idle, place transmission in gear. Using scan tool, monitor vehicle speed. If displayed vehicle speed is greater than zero MPH, go to next step. If displayed vehicle speed is zero MPH, go to step 4 .
3. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Using scan tool, monitor vehicle speed. If displayed vehicle speed is greater than zero MPH, go to step 12 . If displayed vehicle speed is zero MPH, go to next step.
4. Disconnect PCM harness connectors. Connect DVOM between VSS terminals. Rotate drive wheel by hand and note A/C voltage reading. If voltage reading is 0.5 volt or greater, go to next step. If voltage reading is not 0.5 volt or greater, go to step 7 .
5. Check vehicle calibration code. If calibration is correct, go to step 13 . If calibration is incorrect, go to next step.
6. Install proper or most current calibration code. After entering the calibration code, go to step 14 .
7. Ensure ignition is off. Check resistance between VSS terminals. If resistance is greater than 1950 ohms, go to next step. If resistance is not greater than 1950 ohms, go to step 9 .
8. Check for an open in VSS signal circuit. Repair as necessary. After repairs, go to step 14 . If circuit is okay, go to step 11 .
9. If resistance reading in step 7 is 1300-1950 ohms, go to next step. If resistance is not 1300-1500 ohms, go to step 11 .
10. Check for short to ground in VSS signal circuit. Also, check if VSS circuits are shorted together. Repair circuits as necessary. After repairs, go to step 14 . If circuit is okay, go to next step.
11. Remove VSS. Check resistance between VSS terminals. If resistance is 1300-1950 ohms, go to step 13 . If resistance is not 1300-1950 ohms, go to next step.
12. Replace VSS. After replacing sensor, go to step 14 .
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
14. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
15. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Scan tool should indicate vehicle speed whenever drive wheel is turning at greater than 3 MPH. A DTC P0502 can falsely set if engine is "brake torqued" in gear. Disregard DTC if set while drive wheel is not turning. An intermittent problem can be caused by a poor connection, rubbed through wire insulation or broken wire inside insulation. Thoroughly check VSS circuits.

DTC P0506: IDLE SPEED LOW (2.2L "J" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Idle Air Control (IAC) valve is controlled by the Powertrain Control Module (PCM). PCM uses the IAC to maintain a desired idle speed, which can vary depending on input to PCM. Scan tool reads IAC valve pintle position in counts. The higher the counts, the more air that is allowed to by-pass the throttle plate.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0123, P0125, P0131, P0132, P0133, P0134, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0341, P0342, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0601, P0602, P0705, P1133, P1404 and P1441 not set.
2. IAC valve counts are greater than 145.
3. BARO is greater than 72 kPa.
4. ECT greater than 104°F (40°C).
5. Engine run time greater than 20 seconds.
6. Idle speed is less than 100 RPM of desired RPM for greater than 19 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Ensure engine is at normal operating temperature, transmission is in Park or Neutral, parking brake is set and A/C is off. Using scan tool, command IAC valve from 900-2000 RPM. If engine RPM changes smoothly, go to next step. If engine RPM does not change smoothly, go to step 5 .
3. Turn ignition off. Disconnect IAC valve harness connector. Remove IAC valve. Check resistance IAC windings between IAC valve terminals "A" and "B", and then terminals "C" and "D". If each reading is 40-80 ohms, go to next step. If one or both readings are not 40-80 ohms, go to step 13 .
4. Check resistance between IAC valve terminals "B" and "C", and then between terminals "A" and "D". If each reading is infinite, go to step 15 . If one or both readings are not infinite, go to step 13 .
5. Turn ignition on, with engine off. Disconnect IAC valve harness connector. With test light connected to ground, probe all 4 terminals at IAC valve harness connector. If test light illuminates on 2 terminals, go to next step. If test light does not illuminate on 2 terminals, go to step 7 .
6. With test light connected to positive battery terminal, probe all 4 terminals at IAC valve harness connector. If test light illuminates on 2 terminals, go to step 8 . If test light does not illuminate on 2 terminals, go to step 9 .
7. Check for an open or short to ground in IAC valve low and high circuits. Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to step 10 .
8. Start engine and allow it to idle. With test light connected to ground, probe all 4 terminals at IAC valve harness connector. If test light flashes on and off for all 4 terminals, go to step 11 . If test light does not flash on and off for all 4 terminals, go to step 12 .
9. Check for an open or short to voltage in IAC valve low and high circuits. Repair as necessary. After repairs, go to step 15 . If circuits are okay, go to next step.
10. Check PCM connector for poor terminal connections. Repair as necessary. After repairs, go to step 15 . If connector is okay, go to step 14 .
11. Inspect IAC valve passages. Repair as necessary. After repairs, go to step 15 . If IAC passages are okay, go to step 13 .
12. If test light remained on constantly for terminals that did not flash in step 8 , go to step 9 . If test light did not remain on constantly for terminals that did not flash, go to step 7 .
13. Replace IAC valve. After replacing IAC valve, go to step 15 .
14. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
15. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0506. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
16. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

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

1. Fuel system too rich or too lean.
2. Foreign material in throttle body bore or in air induction system.
3. Leaking or restricted intake manifold.
4. Excessive engine overloading.
5. Engine oil viscosity it too high.

DTC P0506: IDLE SPEED LOW (2.4L "J" & "N" BODIES)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Idle Air Control (IAC) valve is controlled by the Powertrain Control Module (PCM). PCM uses the IAC to maintain a desired idle speed, which can vary depending on input to PCM. Scan tool reads IAC valve pintle position in counts. The higher the counts, the greater air flow that is allowed to bypass the throttle plate.

Conditions for setting this DTC are as follows

1. DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0200, P0335, P0341, P0342, P0440, P0442, P0446, P0480, P0502, P0503, P0601, P0602, P1133 and P1441 not set.
2. IAC valve counts are greater than 145.
3. BARO is greater than 72 kPa.
4. ECT greater than 104°F (40°C).
5. Engine run time greater than 20 seconds.
6. TP sensor angle is less than one percent.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for DTCs. If DTCs are present, go to appropriate DTC for diagnosis. If DTCs are not present, go to next step.
3. Start engine. Turn off all accessories (A/C, rear defroster, etc.). Using a scan tool, command RPM up to 1500 RPM, down to 650 RPM, then up to 1500 RPM. If engine RPM is within 50 RPM of each commanded RPM, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If engine RPM is not within 50 RPM of each commanded RPM, go to next step.
4. Turn engine off. Disconnect IAC valve harness connector. Connect IAC Noid Light (J 37027-A) to IAC harness connector. Start engine. Using scan tool, command engine RPM to 1500 RPM, down to 650 RPM, then up to 1500 RPM. Observe noid light. If light cycles from Red to Green (never off), go to step 6 . If light does not cycle from Red to Green, go to next step.
5. Test IAC circuits "A" and "B" for open, short to voltage or short to ground. Repair as necessary. After repairs, go to step 11 . If circuits are okay, go to step 9 .
6. Check throttle body for tampering or restricted air intake system. Remove IAC valve and check for blocked IAC passages or excessive carbon deposits on pintle or throttle bore. Repair as necessary. After repairs, go to step 11 . If no problems were found, go to next step.
7. Check for poor connection at IAC harness connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to next step.
8. Replace IAC valve. After replacing IAC valve, go to step 11 .
9. Check for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step 11 . If connection is okay, go to next step.
10. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
11. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
12. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

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

1. Fuel system too rich or too lean.
2. Foreign material in throttle body bore or in air induction system.
3. Leaking or restricted intake manifold.
4. Excessive engine overloading.
5. Engine oil viscosity is too high.

DTC P0507: IDLE SPEED HIGH (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Idle Air Control (IAC) valve is controlled by the Powertrain Control Module (PCM). PCM uses the IAC to maintain a desired idle speed, which can vary depending on input to PCM. Scan tool reads IAC valve pintle position in counts. The higher the counts, the more air that is allowed to by-pass the throttle plate.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0123, P0125, P0131, P0132, P0133, P0134, P0200, P0300, P0301, P0302, P0303, P0304, P0335, P0341, P0342, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0601, P0602, P0705, P0706, P1133, P1404 and P1441 not set.
2. IAC valve counts are less than 2 counts.
3. BARO is greater than 72 kPa.
4. ECT greater than 104°F (40°C).
5. Idle speed deviates less than desired RPM by greater than 60 RPM for greater than 5 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Ensure engine is at normal operating temperature, transmission is in Park or Neutral, parking brake is set and A/C is off. Using scan tool, command IAC valve from 900 to 2000 RPM. If engine RPM changes smoothly, go to next step. If engine RPM does not change smoothly, go to step 5 .
3. Turn ignition off. Disconnect IAC valve connector. Remove IAC valve. Measure resistance IAC windings between IAC valve terminals "A" and "B", and then terminals "C" and "D". If each reading is 40-80 ohms, go to next step. If one or both readings are not 40-80 ohms, go to step 13 .
4. Check resistance between IAC valve terminals "B" and "C", and then between terminals "A" and "D". If each reading is infinite, go to step 15 . If one or both readings are not infinite, go to step 13 .
5. Turn ignition on, with engine off. Disconnect IAC valve connector. With test light connected to ground, probe all 4 terminals at IAC valve harness connector. If test light illuminates on 2 of the terminals, go to next step. If test light does not illuminate on 2 the terminals, go to step 7 .
6. With test light connected to positive battery terminal, probe all 4 terminals at IAC valve harness connector. If test light illuminates on 2 of the terminals, go to step 8 . If test light does illuminate on 2 of the terminals, go to step 9 .
7. Check for an open or short to ground in IAC valve low and high circuits. Repair as necessary. After repair is completed, go to step 15 . If circuits are okay, go to step 10 .
8. Start engine and allow to idle. With test light connected to ground, probe all 4 terminals at IAC valve harness connector. If test light flashes on and off for all 4 terminals, go to step 11 . If test light does not flash on and off for all 4 terminals, go to step 12 .
9. Check for an open or short to voltage in IAC valve lo and high circuits. Repair as necessary. After repair is completed, go to step 15 . If circuits are okay, go to next step.
10. Check PCM harness connector terminals for poor connections. Repair as necessary. After repairs, go to step 15 . If connector is okay, go to step 14 .
11. Inspect IAC valve passages. Repair as necessary. After repairs, go to step 15 . If IAC passages are okay, go to step 13 .
12. If test light remained on constantly for terminals that did not flash in step 8 , go to step 9 . If test light did not remain on constantly for terminals that did not flash, go to step 7 .
13. Replace IAC valve. After replacing IAC valve, go to step 15 .
14. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
15. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC P0507. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
16. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

Inspect IAC valve connector for proper connection. Check for damaged wiring harness. Check for disconnected, cracked or split vacuum hoses. Check PCV valve for proper installation. Inspect intake manifold for cracks.

DTC P0507: IDLE SPEED HIGH (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

The Idle Air Control (IAC) valve is controlled by the Powertrain Control Module (PCM). PCM uses the IAC to maintain a desired idle speed, which can vary depending on input to PCM. Scan tool reads IAC valve pintle position in counts. The higher the counts, the more air that is allowed to by-pass the throttle plate.

Conditions for setting this DTC are as follows

1. DTCs P0105, P0107, P0108, P0117, P0118, P0122, P0123, P0125, P0131, P0132, P0133, P0134, P0201, P0202, P0203, P0204, P0300, P0325, P0335, P0341, P0342, P0440, P0442, P0446, P0452, P0453, P0480, P0481, P0502, P0503, P0601, P0602, P1133, P1441 and P1621 not set.
2. IAC valve counts are less than 2 counts.
3. BARO is greater than 72 kPa.
4. ECT greater than 104°F (40°C).
5. Idle speed deviates less than desired RPM by greater than 60 RPM for greater than 13 seconds.
6. Engine running for greater than 20 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Ensure engine is at normal operating temperature, transmission is in Park or Neutral, parking brake is set and A/C is off. Using scan tool, command IAC valve from 700 to 1500 RPM. If engine RPM changes smoothly, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If engine RPM does not change smoothly, go to next step.
3. Turn ignition off. Disconnect IAC valve harness connector. Connect Fuel Injector Noid Light (J 37027-A) to IAC harness connector. Start engine. Using scan tool, command engine RPM to 1500 RPM, then to 700 RPM, then back to 1500 RPM. If noid light cycles from Red to Green (never off) when RPM is changed, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If noid light does not cycle when RPM is changed, go to next step.
4. Turn ignition off. Check for an open, short to voltage or short to ground in IAC valve low and high circuits. Repair as necessary. After repairs, go to step 10 . If circuits are okay, go to step 8 .
5. Turn ignition off. Check for vacuum leaks. Check for throttle plate tampering or shaft binding. Check for faulty accelerator cable. Check for faulty or incorrectly installed PCV valve. Repair or replace as necessary. After repairs, go to step 10 . If no problems were found, go to next step.
6. Turn ignition off. Check for poor connections at IAC harness connector. Repair as necessary. After repairs, go to step 10 . If connections are okay, go to next step.
7. Replace IAC valve. After replacing IAC valve, go to step 10 .
8. Turn ignition off. Check for poor connections at PCM harness connector. Repair as necessary. After repairs, go to step 10 . If connections are okay, go to next step.
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
10. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
11. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

Inspect IAC valve connector for proper connection. Check for damaged wiring harness. Check for disconnected, cracked or split vacuum hoses. Check PCV valve for proper installation. Inspect intake manifold for cracks.

DTC P0530: A/C REFRIGERANT PRESSURE SENSOR CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

A/C refrigerant pressure sensor responds to changes in A/C refrigerant high side pressure. Powertrain Control Module (PCM) supplies and monitors 5-volt reference circuit to the pressure sensor. Pressure sensor operating range is 0-450 psi. At zero psi, signal voltage should be about 0.1 volt. At 450 psi or greater, signal voltage should be about 4.9 volts.

Conditions for setting this DTC are as follows

1. A/C pressure sensor signal is greater than 453 psi (4.94 volts) with A/C on.
2. A/C pressure sensor signal is greater than 363 psi (4.0 volts) with A/C off.
3. Refrigerant pressure is less than zero psi (0.20 volt), IAT signal is greater than 32°F (0°C) and DTC P0112 or P0113 is not set.
4. Refrigerant pressure is less than zero psi (0.10 volt), IAT signal is greater than 32°F (0°C) and DTC P0112 or P0113 is set.
5. Conditions exist for greater than 15 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, check for MAP or TP sensor DTCs. If DTCs are present, go to appropriate DTC for diagnosis. If DTCs are not present, go to next step.
3. Scan A/C high side value. If high side value is less than 363 psi (4.0 volts), go to next step. If high side value is not less than 363 psi (4.0 volts), go to step 5 .
4. Unplug A/C pressure sensor connector. If high side value is now less than 76 psi (1.0 volt), go to step 6 . If high side value is not less than 76 psi (1.0 volt), go to step 11 .
5. If A/C high side value is less than zero psi (0.20 volt), go to step 7 . If high side value is not less than zero psi (0.20 volt), go to step 8 .
6. Connect positive DVOM lead to battery voltage. Probe A/C pressure sensor ground circuit with negative DVOM lead. If battery voltage is present, go to step 9 . If battery voltage is not present, go to step 10 .
7. Unplug A/C pressure sensor connector. Using DVOM connected to ground, probe A/C pressure sensor harness 5-volt reference circuit. If DVOM reads about 5 volts, go to step 12 . If DVOM does not read about 5 volts, go to step 13 .
8. Start engine. Turn A/C switch to OFF position. If A/C clutch remains engaged, go to step 14 . If A/C clutch does not remain engaged, go to step 25 .
9. Replace A/C pressure sensor. After replacing sensor, go to step 25 .
10. Repair open or poor connection in pressure sensor ground circuit. After repairs, go to step 25 .
11. If voltage displayed on scan tool with pressure sensor connector unplugged is greater than 4-6 volts, go to step 16 . If voltage displayed is not greater than specification, go to step 17 .
12. Jumper A/C pressure sensor harness connector 5-volt reference circuit to refrigerant pressure signal circuit. If scan tool pressure sensor high side parameter now displays greater than 421 psi (4.6 volts), go to step 9 . If parameter does not display greater than 421 psi (4.6 volts), go to step 18 .
13. Repair open or poor connection in pressure sensor 5-volt reference circuit. After repairs, go to step 25 .
14. Unplug A/C relay. Using a test light connected to battery voltage, probe A/C relay harness control (driver) circuit terminal. If test light illuminates, go to step 19 . If test light does not illuminate, go to step 20 .
15. Replace PCM. Prior to replacement, check PCM terminals, connectors and wiring harness for damage. After replacing PCM, go to step 25 .
16. Check for short to voltage on pressure sensor signal circuit. Repair as necessary. After repairs, go to step 25 . If circuit is okay, go to step 15 .
17. Check pressure sensor signal circuit for short to 5-volt reference. Repair as necessary. After repairs, go to step 25 . If circuit is okay, go to step 15 .
18. Connect DVOM positive lead to battery voltage and probe A/C pressure sensor signal circuit at pressure sensor connector with negative lead. If DVOM reads greater than 0.5 volt, go to step 21 . If DVOM does not read greater than 0.5 volt, go to step 22 .
19. Check A/C clutch relay control circuit for a short to ground between PCM and relay connector. Repair as necessary. After repairs, go to step 25 . If circuit is okay, go to step 15 .
20. If A/C clutch disengages when relay is removed, go to step 23 . If A/C clutch does not disengage when relay is removed, go to step 24 .
21. Check for short to ground or short to sensor ground in A/C pressure sensor signal circuit. Repair as necessary. After repairs, go to step 25 . If circuit is okay, go to step 15 .
22. Check for open in pressure sensor signal circuit. Repair as necessary. After repairs, go to step 25 . If circuit is okay, go to step 15 .
23. Replace A/C compressor relay. After replacing compressor, go to step 25 .
24. Repair short to battery voltage in A/C compressor clutch ignition feed circuit or faulty A/C compressor clutch. After repairs, go to next step.
25. Clear DTCs. Start engine and warm to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates this DTC has ran and passed, go to next step. If scan tool does not indicate that this DTC ran and passed, repeat step 2 .
26. Check for additional DTCs. If additional DTCs are set, service as necessary. If no additional DTCs are set, system is okay. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

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

DTC P0530: A/C REFRIGERANT PRESSURE SENSOR CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

A/C refrigerant pressure sensor responds to changes in A/C refrigerant high side pressure. Powertrain Control Module (PCM) supplies and monitors 5-volt reference circuit to the pressure sensor. Pressure sensor operating range is 0-459 psi. At zero psi, signal voltage should be about 0.1 volt. At 459 psi or greater, signal voltage should be about 4.9 volts.

Conditions for setting this DTC are as follows

1. A/C pressure sensor signal is greater than 453 psi (4.94 volts) with A/C on.
2. A/C pressure sensor signal is greater than 363 psi (4.0 volts) with A/C off.
3. Refrigerant pressure is less than zero psi (0.20 volt), IAT signal is greater than 32°F (0°C) and DTC P0112 or P0113 is not set.
4. Refrigerant pressure is less than zero psi (0.10 volt), IAT signal is greater than 32°F (0°C) and DTC P0112 or P0113 is set.
5. Conditions exist for greater than 15 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Scan A/C high side value. If high side value is greater than 279 psi (3.0 volts), go to next step. If high side value is not greater than 279 psi (3.0 volts), see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
3. Turn ignition off. Disconnect A/C pressure sensor connector. Connect DVOM between battery voltage and A/C refrigerant pressure sensor ground circuit. If battery voltage is present, go to next step. If battery voltage is not present, go to step 5 .
4. Using DVOM, check voltage between ground and A/C refrigerant pressure sensor signal circuit. If voltage reading is greater than 0.5 volt, go to step 6 . If voltage reading is not greater than 0.5 volt, go to step 8 .
5. Check for open or poor connection in A/C refrigerant pressure sensor ground circuit. Repair as necessary. After repairs, go to step 10 . If circuit and connections are okay, go to step 9 .
6. Check for short to voltage in A/C refrigerant pressure sensor signal circuit. Repair as necessary. After repairs, go to step 10 . If circuit is okay, go to step 9 .
7. Replace A/C refrigerant pressure sensor. After replacing sensor, go to step 10 .
8. Replace PCM. Prior to replacement, check PCM terminals, connectors and wiring harness for damage. After replacing PCM, go to next step.
9. Clear DTCs. Start engine and idle to normal operating temperature. Operate vehicle within conditions which set code. If scan tool indicates this DTC has ran and passed, go to next step. If scan does not indicate that this DTC ran and passed, repeat step 2 .
10. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

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

DTC P0562: SYSTEM VOLTAGE LOW

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors system voltage on ignition feed circuit terminals to PCM. If voltage is less than calibrated value, DTC will set.

Conditions for setting DTC

1. System voltage less than 10 volts for 240 seconds.
2. Engine speed greater than 1300 RPM.
3. Fault is present for greater than 4 minutes.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Start engine. Increase engine speed to 1400 RPM. Load electrical system (turn on headlights, high blower, etc.). Using scan tool, check ignition voltage. If voltage reading is less than 10 volts, go to next step. If voltage reading is not less than 10 volts, go to step 8 .
3. Ensure engine speed is still at 1400 RPM. Using DVOM, check voltage at battery. If voltage reading is greater than 12 volts, go to next step. If voltage reading is not greater than 12 volts, repair charging system as necessary.
4. Turn ignition off. Disconnect PCM harness connector. Turn ignition on, with engine off. Using DVOM, check voltage between ground and ignition feed circuit No. 2 terminal at PCM connector. If voltage reading is greater than 10 volts, go to next step. If voltage reading is not greater than 10 volts, go to step 6 .
5. Check for poor connections at PCM harness connector terminals. Repair as necessary. After repairs, go to step 8 . If connector terminals are okay, go to step 7 .
6. Repair poor connection in ignition feed circuit No. 2. After repairs, go to step 8 .
7. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
8. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
9. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

If DTC sets when an accessory is operated, check for poor connection or excessive current draw.

DTC P0563: SYSTEM VOLTAGE HIGH

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) monitors system voltage on ignition feed circuit terminals to PCM. If voltage is greater than calibrated value, DTC will set.

For duplication of DTC, ensure system voltage is greater than 17 volts.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Turn all accessories off. Start and increase engine speed to 1400 RPM. Using scan tool, check ignition voltage. If voltage reading is greater than 17 volts, go to next step. If voltage reading is not greater than 17 volts, go to step 5 .
3. Increase engine speed to 2000 RPM. Using DVOM, check voltage at battery. If voltage reading is less than 17 volts, go to next step. If voltage reading is not less than 17 volts, repair charging system as necessary.
4. Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to next step.
5. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, no problem is indicated at this time. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) . If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .

If DTC sets when an accessory is operated, check for poor connection or excessive current draw.

DTC P0601: PCM MEMORY

Note. For circuit reference, See WIRING DIAGRAMS article.

Electronically Erasable Programmable Read Only (EEPROM) is used to contain program information and calibrations required for engine, transmission and powertrain diagnostics operation. Powertrain Control Module (PCM) uses a value called a checksum for error detection of software. Checksum is a value that is equal to all numbers in software added together. PCM adds all values in the software and if that value does not equal the checksum value, a DTC will set.

For duplication of DTC, PCM must detect more than 3 incorrect checksums.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
3. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
4. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Electronically Erasable Programmable Read Only (EEPROM) is used to contain program information and calibrations required for engine, transmission and powertrain diagnostic operation. EEPROM program can be updated by reprogramming Powertrain Control Module (PCM).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
2. If PCM was just replaced, go to next step. If PCM was not just replaced, go to step 4 .
3. Program replacement PCM using required equipment. If DTC resets, attempt to reprogram PCM again (maximum of 3 times). If DTC still resets, go to next step. If DTC does not reset, go to step 5 .
4. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
5. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
6. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT

Note. For circuit reference, See WIRING DIAGRAMS article.

Transmission range switch is a multi-signal switch that sends a signal indicating gear selection to Powertrain Control Module (PCM). Transmission range switch uses 4 circuits to pull 4 PCM voltage low in various combinations to indicate each gear range. Voltage level of circuits is represented as LOW (grounded) or HIGH (open). The 4 states displayed represents decoder P, A, B and C inputs.

Conditions for setting DTC are: PCM recognizes an invalid PRNDL parameter, vehicle speed greater than 5 MPH and conditions are met for a period longer than 5 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check). After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Observe scan tool and move gear selector through all gear selections. If INVALID is indicated in any range, go to next step. If INVALID is not indicated in any range, go to step 10.
3. Compare scan tool values with transmission range switch valid input combination values. (Scheme 2) If all circuits are indicated as HI, go to next step. If all circuits are not indicated as HI, go to step 5.
4. Check transmission range switch ground circuit for an open or poor connection. Repair as necessary. After repairs, go to step 10. If circuit is okay, go to next step.
5. Move gear selector through all ranges and note which circuit does not correspond with transmission range switch valid input combination values. (Scheme 2) Disconnect transmission range switch connector. Connect a jumper wire between ground and circuit with incorrect value. If jumpered circuit changes from a HI value to a LO value, go to step 8. If jumpered circuit does not change from a HI value to a LO value, go to next step.
6. Check affected circuit for an open or short to ground. Repair as necessary. After repairs, go to step 10. If circuit is okay, go to next step.
7. Check for poor connection at PCM connector. Repair as necessary. After repair is completed, go to step 10. If circuit is okay, go to step 9.
8. Replace defective transmission range switch. After replacing switch, go to step 10.
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
10. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter DTC which was set. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2.
11. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Scheme 2

Monitor scan tool while moving related connectors and wiring harness. Whenever a fault is detected, scan data will change from HI to LO or from LO to HI. Moving gear selector slowly through each gear while monitoring scan tool may also help isolate the problem.

DTC P1133: O2S 1 INSUFFICIENT SWITCHING

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) continuously monitors Oxygen Sensor 1 (O2S 1) activity for 100 seconds. During the monitor period, PCM counts number of times than O2S 1 switches from rich-to-lean and from lean-to-rich. If total number of switches is less than calibrated value, a DTC P1133 will set.

DTC will set under the following conditions: DTC(s) P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300-P0304, P0341, P0404, P0506, P0507, P0601 and P0602 not set, engine speed 1600-2600 RPM, TP sensor angle 9-20 percent. EVAP emission control system commanded open for greater than 36 percent Pulse Width Modulated (PWM), purge learned memory greater than 191 and conditions are present for at least 100 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTCs. If no other DTCs are present, go to next step.
3. Start engine. Ensure engine is at normal operating temperature. Operate vehicle within the conditions required for setting this DTC. Using scan tool, monitor LEAN/RICH transition and note number of switches. Also, note number of RICH/LEAN transitions. If transition is 1-1, go to next step. If transition is not 1-1, go to step 18 .
4. Inspect for proper O2S 1 installation, check O2S 1 connector and wiring for corrosion or damage or check O2S 1 ground circuit. Repair as necessary. After repairs, go to step 9 . If no problems were found, go to next step.
5. Check exhaust manifold for leaks. Repair as necessary. After repairs, repeat step 3 . If exhaust is okay, go to next step.
6. Disconnect O2S 1 connector. Turn ignition on. Using scan tool, monitor O2S 1 voltage. If voltage reading is 407-509 mV, go to next step. If voltage reading is not 407-509 mV, go to step 10 .
7. Connect a jumper wire between ground and signal circuit terminal at O2S 1 harness connector. If voltage reading is less than 200 mV, go to next step. If voltage reading is not less than 200 mV, go to step 11 .
8. Replace oxygen sensor. Determine cause of sensor contamination, otherwise new sensor will be damaged. After repairs, go to step 17 .
9. Repair wiring or terminal as necessary. DO NOT attempt to repair damaged oxygen sensor connector or wiring. If damage is detected, replace oxygen sensor. After repairs, go to step 17 .
10. Repair short to ground in O2S 1 signal circuit. After repairs, go to step 17 .
11. Remove jumper wire. Check voltage between ground and signal circuit at O2S 1 harness connector. If voltage reading is greater than 407 mV, go to next step. If voltage reading is not greater than 407 mV, go to step 13 .
12. Turn ignition off. Disconnect PCM harness connectors. Check resistance between ground and O2S 1 ground circuit at PCM connector. If resistance is less than 5 ohms, go to step 14 . If resistance is not less than 5 ohms, repair open in ground circuit. After repairs, go to step 17 .
13. Turn ignition off. Disconnect PCM harness connectors. Check resistance of signal circuit between O2S 1 harness connector and PCM connector. If resistance is less than 5 ohms, go to step 15 . If resistance is not less 5 ohms, repair open in sensor signal circuit. After repairs, go to step 17 .
14. Check O2S 1 ground circuit terminal connection at PCM connector. Repair or replace terminal as necessary. After repairs, go to step 17 . If ground circuit terminal is okay, go to step 16 .
15. Check O2S 1 signal circuit terminal connection at PCM connector. Repair or replace terminal as necessary. After repairs, go to step 17 . If ground circuit terminal is okay, go to next step.
16. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
17. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
18. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, go to «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

Check if fuel pressure is too high. PCM can compensate for some increase; however, if fuel pressure is too high, DTC will set. Check for leaking injector(s) or faulty fuel pressure regulator. See appropriate SYSTEM & COMPONENT TESTING article.

Check EVAP system for fuel saturation. Disconnect MAP sensor harness connector and see if rich condition is corrected. If rich condition is corrected, check for faulty MAP sensor. Check for oxygen sensor silicone contamination. Check TP sensor. See appropriate SYSTEM & COMPONENT TESTING article.

DTC P1137: REAR HO2S CIRCUIT LOW VOLTAGE DURING POWER ENRICHMENT

Note. For circuit reference, See WIRING DIAGRAMS article.

The catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide. PCM monitors this process by using the rear HO2S (No. 2) signal which indicates the storage capacity of the catalyst. If the catalyst is functioning properly, the HO2S No. 2 signal will be far less active than the signal produced by the front oxygen sensor.

DTC will set under the following conditions: DTC(s) P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0446, P0453, P0506, P0507, P0601, P0602 or P1441 not set, engine in power enrichment mode, battery voltage greater than 10 volts, ECT greater than 167°F (75°C), fuel level greater than 10 percent and engine has been running for greater than 10 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTC(s). If no other DTCs are present, go to next step.
3. Using scan tool, check HO2S No. 2 voltage. If voltage reading is less than 200 mV, go to step 5 . If voltage reading is not less than 200 mV, go to next step.
4. Using scan tool, review the FREEZE FRAME data and record parameters. Start engine and operate vehicle within the Freeze Frame parameters and the conditions for setting this DTC. If HO2S No. 2 voltage is less than 40 mV, go to next step. If HO2S No. 2 voltage is not less than 40 mV, go to step 9 .
5. Turn ignition off. Using a jumper wire connected to ground, connect jumper HO2S No. 2 low circuit terminal on harness connector. Turn ignition on, with engine off. Using scan tool, check HO2S No. 2 voltage reading. If voltage reading is 350-500 mV, go to step 8 . If voltage reading is not 350-500 mV, go to next step.
6. Turn ignition off. Disconnect PCM harness connector. Check HO2S No. 2 circuit for short to ground or short to sensor ground. Repair as necessary. After repairs, go to step 9 . If circuit is okay, go to next step.
7. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 9 .
8. Turn ignition off. Replace HO2S No. 2. After replacing sensor, go to next step.
9. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
10. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by a poor connection, rubbed through wire insulation or broken wire inside insulation.

DTC P1138: REAR HO2S CIRCUIT HIGH VOLTAGE DURING DECEL FUEL CUTOFF

Note. For circuit reference, See WIRING DIAGRAMS article.

The catalytic converter converts any harmful exhaust emissions into harmless water vapor and carbon dioxide. PCM monitors this process by using the rear HO2S (No. 2) signal which indicates the storage capacity of the catalyst. If the catalyst is functioning properly, the HO2S No. 2 signal will be far less active than the signal produced by the front oxygen sensor.

DTC will set under the following conditions: DTC(s) P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0446, P0453, P0506, P0507, P0601, P0602 or P1441 not set, engine in decel fuel cutoff mode, battery voltage greater than 10 volts, ECT greater than 167°F (75°C), fuel level greater than 10 percent and engine has been running for greater than 10 seconds.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTC(s). If no other DTCs are present, go to next step.
3. Using scan tool, check HO2S No. 2 voltage. If voltage reading is greater than 1042 mV, go to step 5 . If voltage reading is not greater than 1042 mV, go to next step.
4. Using scan tool, review the FREEZE FRAME data and record parameters. Start engine and operate vehicle within the Freeze Frame parameters and the conditions for setting this DTC. If HO2S No. 2 voltage is greater than 1042 mV, go to next step. If HO2S No. 2 voltage is not greater than 1042 mV, go to step 10 .
5. Turn ignition off. Connect a DVOM between ground and HO2S No. 2 signal circuit terminal at harness connector. Turn ignition on, with engine off. If voltage reading is zero volts go to next step. If voltage reading is not zero volts, go to step 7 .
6. Turn ignition on, with engine off. Using a jumper wire connected to ground, connect jumper wire to HO2S No. 2 signal and low circuits. Using scan tool, check HO2S No. 2 voltage. If voltage reading is less than 100 mV, go to step 8 . If voltage reading is not less than 100 mV, go to 9 .
7. Repair short to voltage in HO2S No. 2 signal circuit. After repairs, go to step 10 .
8. Turn ignition off. Replace HO2S No. 2. After replacing sensor, go to next step.
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
10. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
11. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay.

An intermittent problem can be caused by a poor connection, rubbed through wire insulation or broken wire inside insulation.

DTC P1171: FUEL SYSTEM LEAN DURING ACCELERATION

Note. For circuit reference, See WIRING DIAGRAMS article.

Powertrain Control Module (PCM) internal circuitry can identify if vehicle fuel system is capable of supplying adequate amounts of fuel during heavy acceleration (power enrichment). When a power enrichment mode of operation is requested, PCM will allow additional fuel to be provided to the engine. If PCM does not detect a rich exhaust, DTC P1171 will set.

Conditions for setting DTC are: DTCs P0131, P0132, P0133, P0134 and P1133 not set, ECT is greater than 70°F (20°C), engine running longer than 20 seconds in "closed-loop", O2S 1 voltage is less than 300 mV for 5 seconds and engine is in power enrichment mode.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. If other DTCs are present, diagnose affected DTC(s). If no other DTCs are present, go to next step.
3. Check fuel level in tank. Add fuel as necessary. If fuel level was low (almost empty), go to step 5 . If fuel level was okay, go to next step.
4. Start engine. Ensure coolant temperature is 167-203°F (75-95°C). Raise engine speed to 1200 RPM. Using scan tool, observe O2S 1 voltage. Voltage should vary within a range of 100-900 mV. Occasionally voltage should increase by greater than 447 mV (during power enrichment mode). If voltage is as specified, go to BASIC FUEL SYSTEM CHECKS in appropriate BASIC DIAGNOSTIC PROCEDURES article. If voltage is not as specified, go to «DTC P0134: O2S CIRCUIT-INSUFFICIENT ACTIVITY-SENSOR 1 (2.2L "J" BODY)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0134-o2s-1-circuit) or «DTC P0134: O2S CIRCUIT-INSUFFICIENT ACTIVITY-SENSOR 1 (2.4L "J" & "N" BODIES)»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0134-o2s-1-circuit) diagnosis.
5. Using scan tool, select CLEAR INFO or CLEAR DTCs function to clear DTCs. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Operate vehicle within conditions required for setting this DTC. Select SPECIFIC DTC function then enter this DTC. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2 .
6. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay. See «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .

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 fuel may cause low O2S 1 voltage during acceleration. Check for defective or plugged fuel injectors.

DTC P1336: CKP SYSTEM VARIATION NOT LEARNED

Note. For circuit reference, See WIRING DIAGRAMS article.

The crankshaft position system variation learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, the crankshaft balancer interrupter rings, and the crankshaft position sensor hall effect switches. The calculated error allows PCM to accurately compensate for reference period variations. The crankshaft position system variation learning feature enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.

The crankshaft position system variation learning procedure must be performed anytime a change is made to the CKP sensor to crankshaft relationship, or if PCM is replaced or reprogrammed.

DTC P1336 set indicates that the crankshaft position system variation values have not been stored in the PCM and the crankshaft position system variation learn procedure must be performed. The learn procedure is required after the following service procedures have been performed, regardless of whether or not DTC P1336 is set

1. PCM replacement or reprogramming.
2. Engine replacement.
3. Crankshaft balancer replacement.
4. Crankshaft position sensor replacement.
5. Any engine repair(s) which disturbs crankshaft/harmonic balancer to crankshaft position sensor relationship.

DTC will set when crankshaft position system variation values are not stored in the PCM memory.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Perform crankshaft position system variation learn position as follows: Install scan tool. Hood closed. Vehicle in Park or Neutral. ECT at 158°F (70°C). Engage parking brake. Block vehicle drive wheels. All accessories off. Enable crankshaft position system variation learning procedure with scan tool. Raise engine speed to 3920 RPM and release throttle as soon as engine cuts out. If scan tool indicates that crankshaft position system variation has been performed, go to step 5 . If scan tool does not indicate that crankshaft position system variation has been performed, go to next step.
3. Attempt crankshaft position system variation learning procedures for about 10 times. If crankshaft variation has been learned, go to step 5 . If crankshaft variation has not been learned, go to next step.
4. Check for problem with crank sensor to crankshaft relationship. Repair as necessary. After repairs, go to next step.
5. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2 .
6. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.

DTC P1336 will only set if PCM has not learned the crankshaft position system variation. PCM only needs to learn this variation once per life cycle of vehicle unless the CKP sensor to crankshaft relationship is disturbed. Removing a part for inspection and then reinstalling the same part is considered a disturbance. A fully warmed up engine is critical to learning the variation correctly. If a valid learn occurs, no other learns can be completed that ignition cycle.

If engine cuts out before the specified learn procedure engine speed or at normal fuel cut-off RPM, the PCM is not in the learn procedure mode. Review crankshaft position system variation learning procedure and re-enable the learn procedure. Verify that scan tool indicates Test In Progress.

DTC P1441: EVAP SYSTEM FLOW DURING NON-PURGE

Note. For circuit reference, See WIRING DIAGRAMS article.

Evaporative Emission (EVAP) system is checked by applying vacuum to EVAP system and monitoring vacuum decay. Powertrain Control Module (PCM) monitors vacuum level by means of fuel tank vacuum sensor input. At a predetermined time, EVAP purge solenoid and EVAP vent solenoid are turned on. This allows engine vacuum to draw a small vacuum on entire EVAP system. DTC will set when EVAP is unable to detect vacuum during diagnostic test.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Turn ignition on, engine off. Using scan tool, check if DTC P0452, P0453 or P0460 is also set. If DTCs are set, diagnose affected DTC(s) first. If these DTCs are not set, go to next step.
3. Turn ignition on, engine off. Using scan tool, command EVAP canister purge valve and vent solenoid on and off. If purge valve and vent solenoid click, go to next step. If purge valve and vent solenoid do not click, perform PCM diagnosis. See appropriate SYSTEM & COMPONENT TESTING article.
4. Turn ignition off. Disconnect purge line from fuel tank at EVAP canister. Turn ignition on. Using scan tool, check fuel tank pressure sensor value. If fuel tank pressure sensor value is zero mm Hg, go to step 6 . If fuel tank pressure sensor value is not zero mm Hg, go to next step.
5. Check for pinched, kinked or plugged purge line from fuel tank to EVAP canister. Repair as necessary. After repairs, go to step 12 . If purge line is okay, go to DTC P0452 or P0453 diagnosis.
6. Zero pressure and vacuum gauges on EVAP Pressure/Purge Diagnostic Station (J-41413). Reconnect all EVAP hardware previously disconnected. Connect EVAP pressure/purge diagnostic station to EVAP service port. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge diagnostic station, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, to step 8 .
7. Maintain EVAP system pressure at 5 in. H2O. Using scan tool, observe FUEL TANK PRESSURE. If scan tool displays 5 in. H2O, go to next step. If scan tool does not display 12 mm Hg, go to «DTC P0452: FUEL TANK PRESSURE SENSOR CIRCUIT-LOW VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0452-fuel-tank-pressure-sensor) or «DTC P0453: FUEL TANK PRESSURE SENSOR CIRCUIT-HIGH VOLTAGE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p0453-fuel-tank-pressure-sensor) diagnosis.
8. Disconnect vacuum hose at EVAP canister purge valve (from throttle body). Connect a hand-held vacuum pump to EVAP canister purge valve vacuum source fitting. Apply 15 in. Hg vacuum. Using scan tool, command EVAP canister purge valve on. If vacuum is maintained, go to next step. If vacuum cannot be maintained, go to step 10 .
9. Check EVAP canister purge valve vacuum hoses for correct routing. If vacuum hoses are routed incorrectly, go to step 11 . If vacuum hoses are routed correctly, see «DIAGNOSTIC AIDS»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l) .
10. Replace EVAP canister purge valve. After replacing canister valve, go to step 12 .
11. Correct EVAP vacuum hose routing. After repairs, go to next step.
12. Disconnect purge line from fuel tank at EVAP canister. Start engine. Using scan tool, activate EVAP SEAL SYSTEM function to seal EVAP system. Connect purge line from fuel tank to EVAP canister. Operate engine at 2500 RPM while monitoring fuel tank pressure value on scan tool. If fuel tank pressure value is zero in. H2O or greater, go to next step. If fuel tank pressure value is not zero in. H2O or greater, repeat step 2 .
13. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, repeat step 2 .
14. Check if additional DTCs are set. Diagnose affected DTC(s). If no additional DTCs are set, system is okay.

Check for incorrect vacuum hose routing to EVAP canister purge valve. Check PCM connector for poor terminal connections. Check for damaged EVAP related wiring harness.

PCM is the control center of the fuel injection system. It constantly looks at information from various sensors, and controls the systems that affect vehicle performance. PCM also performs the diagnostic function of the system. If can recognize operational problems, alert the driver through the MIL, and store DTC(s).

DTC will set when PCM cannot communicate internally.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
3. Using scan tool, CLEAR INFO or CLEAR DTCs function to clear DTC. Start and warm engine to normal operating temperature. Operate vehicle within the conditions foe setting DTC. If scan tool indicates that diagnostic ran and passed, go to next step. If scan tool does not indicate that diagnostic ran and passed, repeat step 2 .
4. Check if any additional DTC(s) are present. If additional DTCs are present, diagnose affected DTC(s) first. If no other DTCs are present, system is okay.

DTC P1626: THEFT DETERRENT SYSTEM FUEL ENABLE SIGNAL CIRCUIT (EXCEPT 2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

A Class 2 serial data communications system is used in order to allow various modules to communicate and share information with each other. Messages carried on the Class 2 data stream are also prioritized. If 2 messages attempt to establish communications on the data line at the same time, the message with lower priority will have to wait.

DTC will set when PCM has lost communication with Body Control Module (BCM) after PCM received a theft passed message from BCM.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Using scan tool, check if this DTC is current or history on scan tool. If this DTC is current, go to next step. If this DTC is not current, go to step 13 .
3. Crank engine. Recheck for DTCs. If this DTC still shows current on the scan tool, go to next step. If this DTC does not show as current on scan tool, go to step 13 .
4. Check if DTC U1064 is also set. If DTC U1064 is set, go to next step. If DTC U1064 is not set, go to step 7 .
5. Check If DTC U1064 is current or history on scan tool. If DTC U1064 is current, diagnose affected DTC. If DTC U1064 does not show as current, go to next step.
6. Crank but do not start engine. Wait at least 5 seconds to verify that DTC U1064 does not become current. Check if DTC U1064 is current. If DTC U1064 is current, diagnose affected DTC. If DTC U1064 is not current, go to next step.
7. Using scan tool, attempt to communicate with BCM. If communication is possible, go to next step. If communication in not possible, go to step 10 .
8. Check for any BCM related DTCs. If a BCM related DTC is set, diagnose affected BCM DTC. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If no BCM related DTC is set, go to next step.
9. Check if BCM indicates that password is valid. If password is valid, go to step 15 . If password is not valid, go to step 11 .
10. Using scan tool, attempt communication with Electronic Brake Control Module (EBCM) and IPC. If communication is possible, go to next step. If communication is not possible, diagnose Data Link Connector (DLC).
11. Disconnect BCM and PCM harness connector. Check serial data between these control modules for open circuit or for poor electrical connections. Repair as necessary. After repairs, go to next step. If circuit is okay, diagnose BCM. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT.
12. Using scan tool, attempt communication with the Body Control Module (BCM). If communication is possible, go to step 14 . If communication is not possible, diagnose BCM. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT.
13. Check harness connector terminals at BCM and PCM. Repair as necessary. After repairs, go to next step. If connector terminals are okay, diagnose BCM. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT.
14. Perform Password Learn Procedure. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. After performing password learn procedure, go to step 16 .
15. Turn ignition off. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
16. Using scan tool, CLEAR INFO or CLEAR DTCs function to clear DTC. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, repeat step 2 .
17. Check if any additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are not set, system is okay.

Attempting to start vehicle by by-passing theft deterrent system or substituting part without performing the password learn procedure may set this DTC. If no password is received, DTC P1631 and P1632 may be set.

Disconnect and inspect PCM connector. Inspect for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Reviewing FAILURE RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.

DTC P1626: THEFT DETERRENT SYSTEM FUEL ENABLE SIGNAL CIRCUIT (2.4L "N" BODY)

Note. For circuit reference, See WIRING DIAGRAMS article.

A Class 2 serial data communications system is used in order to allow various modules to communicate and share information with each other. Messages carried on the Class 2 data stream are also prioritized. If 2 messages attempt to establish communications on the data line at the same time, the message with lower priority will have to wait.

DTC will set when PCM has lost communication with Body Control Module (BCM) after PCM received a theft passed message from BCM.

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Using scan tool, check if DTC U1064 is also set. If DTC U1064 is also set, diagnose DTC first. If DTC U1064 is not set, go to next step.
3. Check if a Body Control Module (BCM) related DTC is set. If a BCM DTC is also set, diagnose BCM DTC first. If no BCM DTC is set, go to next step. If no components were tampered, go to next step.
4. Using scan tool, check if BCM password is valid. If password is valid, go to next step. If password is not valid, diagnose BCM system. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT.
5. Perform Password Learn Procedure. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. After performing password learn procedure, go to step 8. If password cannot be learned, go to next step.
6. Check BCM and PCM harness connectors and terminals. Repair as necessary. After repairs, go to step 8 . If connectors and terminals are okay, go to next step.
7. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
8. Using scan tool, CLEAR INFO or CLEAR DTCs function to clear DTC. Start and warm engine to normal operating temperature. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this diagnostic ran and passed, go to next step. If scan tool does not indicate that this diagnostic ran and passed, repeat step 2 .
9. Check if any additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are not set, system is okay.

Attempting to start vehicle by by-passing theft deterrent system or substituting part without performing the password learn procedure may set this DTC. If no password is received, DTC P1631 and P1632 may be set.

Disconnect and inspect PCM connector. Inspect for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Reviewing FAILURE RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.

DTC P1630: THEFT DETERRENT SYSTEM LEARN MODE ACTIVE

Note. For circuit reference, See WIRING DIAGRAMS article.

Vehicle Theft Deterrent (VTD) system, called the PassLock(R) II, disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Control Module (BCM) and PCM.

When ignition switch is first turned on, PCM looks for a password from the BCM through the Class 2 serial data circuit. If password is not recognized or not present, PCM will disable engine. There are 2 tamper detection modes: no password received and incorrect or disable password received (3 invalid passwords received).

DTC will set when PassLock(R) II password learn procedure has been interrupted or ready to learn, PCM received an incorrect password or PCM finished the 10 minute learn pending timer (ignition on for 10 minutes).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Using scan tool, check if DTC P1630 is active. If DTC P1630 is active, go to next step. If DTC P1630 is not active, go to step 10 .
3. Check if DTC P1632 is also set. If DTC P1632 is set, go to next step. If DTC P1632 is not set, go to step 7 .
4. Check if DTC U1064 is also set. If DTC U1064 is set, diagnose DTC U1064. If DTC U1064 is not set, go to next step.
5. Check for any Body Control Module (BCM) related DTCs. If BCM DTCs are set, affected diagnose BCM DTC. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If no BCM related BCM is set, go to next step.
6. Check for any PassLock(R) Theft Deterrent system related DTCs. If theft deterrent DTCs are set, perform «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . If no theft deterrent DTCs are set, go to step 8 .
7. Perform Password Learn Procedure. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. Attempt to start engine. If engine starts and continues to run, go to step 6 . If engine does not start or starts and then stalls, go to next step.
8. Perform Body Control Module (BCM) system check. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If a problem is found, repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
10. Using scan tool, clear DTCs. Warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this DTC ran and passed, go to next step. If scan tool does not indicate that this DTC ran and passed, repeat step 2 .
11. Check if additional DTC are set. Diagnose affected DTCs. If no other DTCs are set, system is okay.

Attempting to start vehicle by by-passing the theft deterrent system or substituting parts without performing the password learn procedure may set DTC P1631 and P1632. If no password is received, DTC P1632 and U1064 may set. PCM must be reflashed to allow new password to be learned if BCM is replaced. Turn ignition off for at least 30 seconds then on for PCM to learn the new BCM password.

An intermittent may be caused by poor connection, rubbed-through wire insulation or a broken wire inside insulation.

DTC P1631: THEFT DETERRENT FUEL ENABLE SIGNAL NOT CORRECT

Note. For circuit reference, See WIRING DIAGRAMS article.

Vehicle Theft Deterrent (VTD) system, called the PassLock(R) II, disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Control Module (BCM) and PCM.

When ignition switch is first turned on, PCM looks for a password from the BCM through the Class 2 serial data circuit. If password is not recognized or not present, PCM will disable engine. There are 2 tamper detection modes: no password received and incorrect or disable password received (3 invalid passwords received).

DTC will set when PassLock(R) II password learn procedure has been interrupted or ready to learn, PCM received an incorrect password or PCM finished the 10 minute learn pending timer (ignition on for 10 minutes).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Using scan tool, display data list for Body Control Module (BCM). See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If no BCM related BCM is set, go to next step.
3. Perform Password Learn Procedure. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. Diagnose theft deterrent DTCs.
4. Check if any theft deterrent related DTCs are set. Diagnose affected DTCs. If no theft deterrent related DTCs are set, go to next step.
5. Using scan tool, check for new DTCs. If new DTCs are set, diagnose affected DTCs. If not new DTCs are set, go to next step.
6. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
7. Using scan tool, clear DTCs. Warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this DTC ran and passed, go to next step. If scan tool does not indicate that this DTC ran and passed, repeat step 2 .
8. Check if additional DTCs are set. Diagnose affected DTCs. If no other DTCs are set, system is okay.

Attempting to start vehicle by by-passing the theft deterrent system or substituting parts without performing the password learn procedure may set DTC P1631 and P1632. If no password is received, DTC P1631 and U1632 may set. PCM must be reflashed to allow new password to be learned if BCM is replaced. Turn ignition off for at least 30 seconds then on for PCM to learn the new password.

An intermittent may be caused by poor connection, rubbed-through wire insulation or a broken wire inside insulation.

DTC P1632: THEFT DETERRENT FUEL DISABLE SIGNAL RECEIVED

Note. For circuit reference, See WIRING DIAGRAMS article.

Vehicle Theft Deterrent (VTD) system, called the PassLock(R) II, disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Control Module (BCM) and PCM.

When ignition switch is first turned on, PCM looks for a password from the BCM through the Class 2 serial data circuit. If password is not recognized or not present, PCM will disable engine. There are 2 tamper detection modes: no password received and incorrect or disable password received (3 invalid passwords received).

DTC will set when PassLock(R) II password learn procedure has been interrupted or ready to learn, PCM received an incorrect password or PCM finished the 10 minute learn pending timer (ignition on for 10 minutes).

1. Perform On-Board Diagnostic (OBD) system check. See «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . After performing OBD system check, go to next step.
2. Using scan tool, check if DTC U1064 is also set. If DTC U1064 is set, diagnose DTC. If DTC U1064 is not set, go to next step.
3. Check if DTC P1630 and P1632 are set together. If they are set together, diagnose DTC P1630 first. See «DTC P1630: THEFT DETERRENT SYSTEM LEARN MODE ACTIVE»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p1630-theft-deterrent-system-learn) . If DTC P1630 and P1632 are not set together, go to next step.
4. Check if DTC P1631 and P1632 are set together. If they are set together, diagnose DTC P1631 first. See «DTC P1631: THEFT DETERRENT FUEL ENABLE SIGNAL NOT CORRECT»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__dtc-p1631-theft-deterrent-fuel-enable) . If DTC P1631 and P1632 are not set together, go to next step.
5. Check for any Body Control Module (BCM) related DTCs. If BCM DTCs are set, affected diagnose BCM DTC. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If no BCM related BCM is set, go to next step.
6. Check for any PassLock(R) Theft Deterrent system related DTCs. If theft deterrent DTCs are set, perform «ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/cavalier/iii-1995-2005/remont/testing-diagnostics/#engine-controls-self-diagnostics-22l-24l__on-board-diagnostic-obd-system-check) . If no theft deterrent DTCs are set, go to step 8 .
7. Perform Password Learn Procedure. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. Attempt to start engine. If engine starts and continues to run, go to step 6 . If engine does not start or starts and then stalls, go to next step.
8. Perform Body Control Module (BCM) system check. See appropriate BODY CONTROL MODULES (BCM) article in ACCESSORIES & EQUIPMENT. If a problem is found, repair as necessary. After repairs, go to step 10 . If no problem is found, go to next step.
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
10. Using scan tool, clear DTCs. Warm engine to normal operating temperature. Operate vehicle within the conditions for setting this DTC. If scan tool indicates that this DTC ran and passed, go to next step. If scan tool does not indicate that this DTC ran and passed, repeat step 2 .
11. Check if additional DTC are set. Diagnose affected DTCs. If no other DTCs are set, system is okay.

Attempting to start vehicle by by-passing the theft deterrent system or substituting parts without performing the password learn procedure may set DTC. If no password is received, DTC P1610 and P1632 may set. PCM must be reflashed to allow new password to be learned if BCM is replaced. Turn ignition off for at least 30 seconds then on for PCM to learn the new password.

An intermittent may be caused by poor connection, rubbed-through wire insulation or a broken wire inside insulation.

See also:
• MODEL IDENTIFICATION
• DIAGNOSTIC PROCEDURE
• ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
• HARD OR INTERMITTENT TROUBLE CODE DETERMINATION
• SCAN TOOL USAGE
• DLC DIAGNOSIS OR NO SCAN TOOL DATA
• DIAGNOSTIC TROUBLE CODE DEFINITIONS
• MIL INOPERATIVE
• MIL ON STEADY
• P0105
• P0107
• P0108
• P0112
• P0113
• P0117
• P0118
• P0122
• P0123
• P0125
• P0128
• P0130
• P0131
• P0132
• P0133
• P0134
• P0137
• P0138
• P0140
• P0141
• P0172
• P0201
• P0202
• P0203
• P0204
• P0300
• P0300
• P0301
• P0302
• P0303
• P0304
• P0325
• P0335
• P0336
• P0340
• P0341
• P0420
• P0440
• P0442
• P0446
• P0452
• P0453
• P0461
• P0462
• P0463
• P0480
• P0481
• P0502
• P0506
• P0506
• P0507
• P0530
• P0562
• P0563
• P0601
• P0705
• P1133
• P1137
• P1138
• P1171
• P1336
• P1441
• P1626
• P1630
• P1631
• P1632
• CLEARING DIAGNOSTIC TROUBLE CODES
• DTC P0507: IDLE SPEED HIGH (EXCEPT 2.4L "N" BODY)