Engine Controls - Tests W/codes - 2.4l Chevrolet Malibu V

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 the BASIC TESTING - 2.4L article. Failure to do so may result in lost diagnostic time.

If no faults were found while performing basic diagnostic procedures, proceed with DIAGNOSTIC PROCEDURE under SELF-DIAGNOSTIC SYSTEM. If no fault codes are present and driveability problems exist, proceed to TESTS W/O CODES - 2.4L article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.). If only intermittent codes are present, see INTERMITTENTS in TESTS W/O CODES - 2.4L article.

DIAGNOSTIC SYSTEM

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/VCM is equipped with a self-diagnostic system which detects system failures or abnormalities. When a malfunction occurs, PCM/VCM 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 as intermittent failures.

There are 4 types of DTC category

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

Hard Failures

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

If a sensor fails, PCM/VCM 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 go out about 10 seconds after intermittent fault goes away. Corresponding DTC, however, will be retained in PCM/VCM memory. If related fault does not reoccur within 50 engine starts, trouble code will be erased from control module memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES - 2.4L article.

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

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

DTC INFO MODE

Used to search for a specific type of stored DTC information. There are 7 choices in this mode. Technician may be instructed to test DTC(s) 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.

DTC STATUS

This selection will display any DTC(s) 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. DTC test which run and passed will cause that affected DTC to be removed from scan tool screen.

FAIL THIS IGN.

This selection will display all DTCs that have failed during the present ignition cycle.

HISTORY

This selection will display only DTC(s) that are stored in the control module's history memory. It will not type "B" 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.

LAST TEST FAIL

This selection will display only DTCs that have failed the last time the test ran. The last test may have ran during the previous ignition cycle, if a type "A" or "B" DTC is displayed. For type "C" DTCs, the last failure must have occurred during the current ignition cycle to be displayed as LAST TEST FAIL.

MIL REQUEST

This selection will display only DTCs that are requesting the MIL. Type "C" DTCs cannot be displayed using this option. This selection will report type "B" DTCs only after the MIL has been requested.

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.

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.

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.

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.

NOT RUN THIS IGN.

Not Run This Ignition message indicates the selected diagnostic test has not run this ignition cycle.

TEST RAN AND PASSED

This message indicates the selected diagnostic test has

1. Passed the last test.
2. Ran and passed during this ignition cycle.
3. Ran and passed since DTCs were last cleared.
4. Test has not failed since DTCs were last cleared.

If this message is displayed, repair is done. 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 following order

1. Ensure all engine systems not related to computer system are operating properly. DO NOT proceed with testing unless all other problems have been repaired. Powertrain On-Board Diagnostic (OBD) System Check must be performed before using specific DTC testing procedure. See «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) .
2. If DTC(s) were displayed, determine whether codes are hard or intermittent trouble codes. Hard codes will cause MIL to illuminate continuously while engine is running. See «HARD OR INTERMITTENT TROUBLE CODE DETERMINATION»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__hard-or-intermittent-trouble-code-determination) . For diagnosing hard codes, proceed to appropriate DTC test. For diagnosing intermittent codes, proceed to INTERMITTENTS in TESTS W/O CODES - 2.4L article.
3. If no DTCs are present and a driveability problem exists, refer to SYMPTOMS in TESTS W/O CODES - 2.4L article. Doing so will help identify proper system or component to check in SYSTEM/COMPONENT TESTS - 2.4L article.
4. After necessary repairs are made, clear DTCs, verify vehicle will enter "closed loop" operation and ensure DTC does not reset.

POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK

Note. Tech 1 or 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 BASIC TESTING - 2.4L 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 diagnostic circuit check, if no codes are indicated and driveability problems still exist, see TESTS W/O CODES - 2.4L article and SCAN TOOL USAGE.

1. Turn ignition on with engine off. If Malfunction Indicator Light (MIL) illuminates, go to next step. If MIL does not illuminate, go to MIL INOPERATIVE.
2. Turn ignition off. Install scan tool and follow scan tool manufacturer's instructions to proceed with test. Turn ignition on. 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.
3. Using scan tool, command MIL to turn off. If MIL turns off, go to next step. If MIL does not turn off, go to MIL ON STEADY.
4. Using scan tool, check if any DTCs are present. If DTCs are present, go to next step. If DTCs are not present, go to step 6).
5. Using scan tool, store FREEZE FRAME and FAILURE RECORDS data. Diagnose any stored DTC.
6. Start engine. If engine starts and runs, go to next step. If engine does not start, or starts and dies, go to NO START DIAGNOSIS in BASIC TESTING - 2.4L article.
7. Turn ignition on with engine off. Check Engine Coolant Temperature (ECT) and TP sensors for proper operation. Start and warm engine to normal operating temperature. Check ECT sensor, MAP sensor, O2 sensors, and IAC valve for proper operation. Compare scan tool engine data with actual control system data values. If values are within limits, see TESTS W/O CODES - 2.4L article. If values are not within limits, go to SYSTEM/COMPONENT TESTS - 2.4L article.

MIL INOPERATIVE

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on with engine off. If Malfunction Indicator Light (MIL) illuminates, go to next step. If MIL does not illuminate, go to step 4).
3. Check for poor connections at battery feed circuit or ignition positive voltage 1 circuit. 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 connection on engine block or PCM connector ground terminals. Repair as necessary. After repairs, go to step 22).
6. Turn ignition off. Disconnect PCM connectors. Turn ignition on. Using a test light connected to ground, probe MIL control circuit. See WIRING DIAGRAMS - 2.4L 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 blown, go to step 11).
8. Check for poor battery feed, ignition positive voltage 1 or MIL control circuit connections. 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 connectors. Turn ignition on. Using a test light connected to ground, probe ignition positive voltage 2 circuit. See WIRING DIAGRAMS - 2.4L 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 - 2.4L 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 ignition battery voltage 1 circuit. See WIRING DIAGRAMS - 2.4L article. If test light illuminates, go to step 18). If test light does not illuminate, go to step 19).
16. Repair open in battery feed circuit. After repairs, go to step 22).
17. Check for open in ignition feed circuit or fuse to MIL. See WIRING DIAGRAMS - 2.4L article. Repair as necessary. After repairs, go to step 22). If circuit or fuse is okay, go to step 20).
18. Check for poor connections at battery feed circuit or ignition positive voltage 1 circuit. Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 21).
19. Repair open in ignition positive voltage 1 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 connection on engine block or PCM connector. Repair as necessary. After repairs, go to next step. If connection and connector are okay, go to step 12).
22. Warm engine to operating temperature. Check for DTCs. If DTCs are present, diagnose affected DTCs. If DTCs are not present, system is okay.

MIL ON STEADY

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on with engine off. MIL should illuminate. If MIL does not illuminate, go to MIL INOPERATIVE. If MIL illuminates, go to next step.
3. Install scan tool. Using scan tool, command MIL on and off. If MIL turns on and off when commanded, go to step 8). If MIL does not turn on and off when 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 - 2.4L article. Repair as necessary. After repairs, go to step 8). If circuit is okay, go to next step.
6. Replace Instrument Panel Cluster (IPC). After IPC replacement, go to step 8).
7. Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
8. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start, or starts and dies, go to step 1).
9. Warm engine to operating temperature. Check for DTCs. If DTCs are present, see «TROUBLE CODE DEFINITION»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) table. If DTCs are not present, system is okay.

DLC DIAGNOSIS OR NO SCAN TOOL DATA

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on with engine off. Install scan tool. If scan tool is equipped with external power source, ensure power source and ground are okay. If scan tool powers up, go to next step. If scan tool does not power up, go to step 4).
3. Disconnect scan tool. Using a test light connected to ground, probe DLC class 2 serial data circuit. See WIRING DIAGRAMS - 2.4L article. If test light does not illuminate, go to step 5). If test light illuminates, go to step 6).
4. Using a test light connected to ground, probe DLC battery feed circuit. See WIRING DIAGRAMS - 2.4L article. If test light illuminates, go to step 7). If test light does illuminate, go to step 8).
5. Using a test light connected to battery voltage, probe DLC class 2 serial data circuit. See WIRING DIAGRAMS - 2.4L article. If test light does not illuminate, go to step 9). If test light does illuminate, go to step 10).
6. Check for short to voltage in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to step 11).
7. Using a test light connected to battery voltage, probe DLC ground circuits. See WIRING DIAGRAMS - 2.4L article. If test light illuminates for both ground circuits, go to step 15). If test light does not illuminate for both ground circuits, go to step 12).
8. Repair open or short to ground in DLC battery feed circuit. After repairs, go to step 17).
9. Check for open or poor connection in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to step 13).
10. Check for short to ground in class 2 serial data circuit. Repair as necessary. After repairs, go to step 17). If circuit is okay, go to next step.
11. Replace PCM. Perform PCM relearn procedures. After repairs, go to step 17).
12. Repair open or poor connections in DLC ground circuits. After repairs, go to step 17).
13. Reinstall scan tool. If scan tool can communicate with PCM, go to step 17). If scan tool can not communicate with PCM, go to next step.
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 step 11). If scan tool does not operate properly, go to step 16).
15. Check DLC for proper terminal tension or excessive resistance. Repair as necessary. After repairs, go to step 17). If terminals are okay, go to next step.
16. Scan tool is malfunctioning. Using scan tool manual, repair as necessary. After repairs, go to next step.
17. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and then dies, go to step 1).
18. Warm engine to operating temperature. Check for DTCs. If DTCs are present, diagnose DTCs. If DTCs are not present, system is okay.

READING TROUBLE CODES

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

TROUBLE CODE DEFINITIONS

TROUBLE CODE DEFINITION

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 (DTC)»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__clearing-diagnostic-trouble-codes-dtc) .
2. Apply parking brake, and place transmission in Neutral or Park. Block drive wheels, and start engine. MIL should go out. Operate warm engine at specified RPM 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 failure 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 (DTC)

To clear DTCs from memory, either to determine if malfunction will occur again or after making necessary repairs, disconnect power supply to ECM/PCM/VCM for at least 30 seconds or clear codes using a scan tool.

ECM/PCM/VCM LOCATION

On most models, ECM/PCM/VCM is located behind right or left side of dash, behind right or left kick panel, or on left or right side of engine compartment. For a more precise location, see COMPONENT LOCATIONS in SYSTEM/COMPONENT TESTS - 2.4L article.

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 plugged into 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 lights and 6 jumper wires 6" long (one wire with female connectors at both ends, one wire with male connectors at both ends and 4 wires with male and female connectors at opposite ends). 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 POWERTRAIN 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 plugged into 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 cuts down 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 ECM/PCM/VCM; 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. See SCAN DATA.

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 TESTS W/O CODES - 2.4L article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.

DIAGNOSTIC TROUBLE CODES

Note. Before clearing DTCs, perform procedures under POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . Record FREEZE FRAME and FAILURE RECORDS for reference during testing. Data will be erased when DTCs are cleared. If ECM/PCM/VCM is replaced, NEW ECM/PCM/VCM must be programmed using special manufacturer's equipment.

DTC P0106 - MAP SENSOR SYSTEM PERFORMANCE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Circuit Description

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).

Conditions for setting DTC

1. DTCs P0107, P0108, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0341, P0342, P0404, P0405, P0440, P0442, P0446, P0452, P0453, P0502, P0506, P0507, P0601, P0602 or P1442 not set.
2. Engine speed greater than 900 RPM.
3. Initial idle MAP greater than 60 kPa.
4. TP less than 50 percent and changes are greater than 8 percent.

Diagnostic Procedures

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off. Using scan tool, compare BARO reading with a known-good vehicle. If BARO reading is normal for the altitude, go to next step. If BARO reading is not normal for the altitude, go to step 7).
3. Start engine while watching MAP sensor value. If MAP sensor value changes, go to next step. If MAP value does not change, go to step 5).
4. With engine still running, snap throttle while watching MAP sensor display on scan tool. If MAP sensor value change rapidly with throttle position changes, go to step 8). If MAP value does not change rapidly, go to step 6).
5. Disconnect MAP sensor vacuum hose. Install a hand-held vacuum pump to MAP sensor. Turn ignition on, with engine off. Apply 15 in. Hg to MAP sensor. Monitor MAP sensor value on scan tool. If MAP sensor value changes, go to next step. If MAP sensor value does not change, go to step 7).
6. Remove MAP sensor vacuum hose from manifold port. Inspect manifold port and hose for restriction. Repair as necessary. After repairs, go to step 8). If no problems were found, go to next step.
7. Replace MAP sensor. After replacing sensor, 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. Drive vehicle at a steady speed. 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, repeat step 2).
9. Check for additional DTCs. Diagnose affected DTCs as necessary. If no other DTCs are set, system is okay. See DIAGNOSTIC AIDS.

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.

DTC P0107 - MAP SENSOR CIRCUIT LOW VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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).

Conditions required to test for DTC are

1. MAP is less than 14 kPa.
2. Engine speed less than 1000 RPM.
3. Throttle Position (TP) sensor angle greater than 15 percent.
4. DTC P0122 or P0123 not set.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 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, repeat step 3). If MAP sensor voltage is not less than .25 volt, see DIAGNOSTIC AIDS.
5. Disconnect and inspect MAP sensor connector. If connector is okay, go to step 8). If connector is not okay, go to step 9).
6. Turn ignition off. Disconnect jumper wire from MAP sensor connector. Connect a test light between battery voltage and 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 less 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 okay, go to step 10). If 5-volt reference circuit is not okay, go to step 11).
8. Repair connector pins and/or wiring as necessary. After repairs, go to step 15).
9. Replace MAP sensor. After replacing sensor, go to step 15).
10. Repair 5-volt reference circuit to MAP sensor. After repairs, go to step 14).
11. Remove MAP sensor 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 next step.
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 15).
13. Check MAP sensor signal circuit for an open or short to ground. If circuit is open or shorted to ground, go to next step. If circuit is okay, repeat step 11).
14. Repair MAP sensor signal circuit. After repairs, go to next step.
15. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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, repeat 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 - 2.4L 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).

Conditions for setting DTC are

1. MAP sensor is greater than 82 kPa.
2. Vehicle speed sensor less than one MPH.
3. Throttle Position (TP) sensor angle less than 12 percent.
4. Engine run time is greater than 20-40 seconds.
5. DTC P0122 or P0123 not set.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 greater than 4 volts, 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 one volt or less, go to step 6).
4. Turn ignition on, 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 greater than 4 volts, see DIAGNOSTIC AIDS.
5. Using test light connected to battery voltage, probe MAP sensor signal ground circuit. If test light illuminates, go to step 7). If test light does not illuminate, go to step 11).
6. 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 connected to ground, probe 5-volt reference circuit. If DVOM reads about 5 volts, go to next step. If DVOM does not read about 5 volts, 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. 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 open in MAP sensor ground circuit. Repair as necessary. After repairs, go to step 14).
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 14).
13. Replace MAP sensor. After replacing sensor, go to next step.
14. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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, repeat 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.

IAT TEMPERATURE-TO-RESISTANCE VALUES

IAT TEMPERATURE-TO-RESISTANCE VALUES

DTC P0112 - IAT SENSOR CIRCUIT LOW VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 will set.

Conditions for setting this DTC are as follows

1. Engine run time is greater than 6 minutes.
2. Vehicle speed greater than 15 MPH.
3. IAT sensor signal voltage indicates IAT is greater than 262°F (128°C).

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. Go to DIAGNOSTIC AIDS.
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 replacing sensor, go to step 9).
6. Connect a test light between positive battery terminal and signal circuit terminal at IAT sensor 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 voltage and IAT sensor signal circuit terminal at IAT 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 replacing PCM, go to next step.
10. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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, repeat 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 IAT TEMPERATURE-TO-RESISTANCE VALUES table.

DTC P0113 - IAT SENSOR CIRCUIT HIGH VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 than the normal operating range of the sensor, DTC will set.

Conditions for setting this DTC

1. Engine run time greater than 6 minutes.
2. ECT greater than -40°F (-40°C).
3. Vehicle speed greater than 24 MPH.
4. IAT sensor signal voltage indicates air temperature is less than -40°F (-40°C).

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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, 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.
4. Disconnect IAT sensor connector. Connect a jumper wire between signal circuit and sensor ground circuit terminals 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 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. Disconnect and inspect IAT sensor harness connector. Repair connector/terminals as necessary. After repairs, go to step 12). If connector is okay, go to step 10).
7. Check for an open IAT sensor ground circuit. Repair wiring as necessary. After repairs, go to step 12). If circuit is okay, go to step 9).
8. Check for an open IAT sensor signal circuit. Repair wiring 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 repair is completed, go to step 12).
11. Replace PCM. Program replacement PCM using required equipment. After replacement is completed, go to next step.
12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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 P0113. 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).
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 IAT TEMPERATURE-TO-RESISTANCE VALUES table.

ECT TEMPERATURE-TO-RESISTANCE VALUES

ECT TEMPERATURE-TO-RESISTANCE VALUES

DTC P0117 - ECT SENSOR CIRCUIT LOW VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 PCM senses a signal voltage lower than the normal operating range of the sensor, DTC will set.

Conditions for setting this DTC are as follows

1. Engine run time is greater than 2 minutes.
2. ECT sensor signal voltage indicates engine coolant temperature is greater than 280°F (138°C) for 6.25 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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.
4. Disconnect ECT sensor connector. 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 replacing sensor, 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 DTCs or CLEAR INFO function to 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 P0117. If scan tool indicates TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, return to 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.

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 ECT TEMPERATURE-TO-RESISTANCE VALUES table.

DTC P0118 - ECT SENSOR CIRCUIT HIGH VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 PCM senses a signal voltage lower than the normal operating range of the sensor, DTC will set.

Conditions for setting this DTC are as follows

1. Engine run time is greater than 2 minutes.
2. ECT sensor signal voltage indicates engine coolant temperature is less than -40°F (-40°C) for 6.25 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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, 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), go to DIAGNOSTIC AIDS.
4. Disconnect ECT sensor harness connector. Connect a jumper wire between ECT signal circuit and sensor ground circuit terminals at ECT sensor harness connector. 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. Disconnect and inspect ECT sensor connector. Repair as necessary. After repairs, go to step 12). If connector is okay, go to step 10).
7. 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. Check for open ECT sensor signal circuit. Repair wiring 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 replacing sensor, go to step 12).
11. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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 P0118. 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).
13. 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 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 ECT TEMPERATURE-TO-RESISTANCE VALUES table.

DTC P0121 - TP SENSOR SYSTEM PERFORMANCE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

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

Conditions required to test for DTC are

1. DTC(s) P0106, P0107, P0108, P0171, P0172, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0335, P0341, P0342, P0404, P0405, P0440, P0442, P0452, P0453, P0502, P0506, P0507, P0601, P0602 or P1441 not set.
2. TP sensor angle greater than 7 percent after attempting to auto-zero.
3. ECT greater than 68°F (20°C).
4. TP stable at plus or minus 2 percent.
5. MAP less than 37 kPa.
6. TP angle greater than specified percentages at the given RPMs for at least 6 seconds: 2 percent at 0 RPM 10 percent at 800 RPM 20 percent at 1600 RPM 25 percent at 2400 RPM 30 percent at 3200 RPM 35 percent at 4000-4800 RPM 40 percent at 5600 RPM 40 percent at 6400 RPM

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off. Observing scan tool, depress accelerator to floor, then slowly release pedal. TP sensor angle value should increase steadily to about 98 percent when pedal is depressed and decrease steadily to about one percent when pedal is released. If TP sensor angle value is as specified, go to next step. If TP sensor angle value is not as specified, go to step 4).
3. If scan tool displays a TP voltage at less than .8 volt when throttle is fully closed, go to next step. If TP voltage is not less than .8 volt when throttle is fully closed, 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 TP sensor angle value-versus-RPM value is greater than specified value in conditions for setting DTC, go to next step. If TP sensor angle value-versus-RPM value is not greater than the specified value in conditions for setting DTC, go to step 12).
5. Disconnect TP sensor connector. Observe TP sensor display on scan tool. If TP sensor voltage is less than .5 volt, go to next step. If TP sensor voltage is .5 volt or greater, go to step 7).
6. Using a test light connected to ground, probe TP sensor battery circuit at harness connector. Connect DVOM between chassis ground and harness connector ground circuit. If DVOM reads greater than .5 volt, go to step 8). If DVOM does not read greater than .5 volt, go to step 9).
7. Check TP signal circuit for short to voltage. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 15).
8. Check TP sensor ground circuit for high resistance between PCM and TP sensor connectors. Check TP sensor ground circuit for poor connection. Repair as necessary. After repairs are complete, go to step 16). If circuit is okay, go to step 14).
9. Using DVOM connected to ground, probe 5-volt reference circuit at TP sensor connector. If DVOM reads about 5 volts, go to step 13). If DVOM does not read about 5 volts, go to next step.
10. Disconnect EGR valve, MAP, A/C and fuel pressure sensor harness connectors. Probe 5-volt reference circuit to TP sensor harness connector. If DVOM reads about 5 volts, go to next step. If DVOM does not read about 5 volts, go to step 12).
11. Leaving DVOM connected to TP sensor 5-volt reference circuit, reconnect each disconnected component one at a time until voltage reading displays other than 5 volts. Replace component that caused voltage reading to be other than 5 volts. After replacing component, go to step 16).
12. Check for short to voltage in TP sensor 5-volt reference circuit. Repair as necessary. After repairs are complete, go to step 16). If circuit is okay, go to step 15).
13. Replace TP sensor. After replacing sensor, go to step 16).
14. Check PCM harness connector for poor connection or resistance. Repair as necessary. After repairs, go to step 16). If connection is okay, go to next step.
15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
16. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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 P0121. 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).
17. 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 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 present when DTC was set.

DTC P0122 - TP SENSOR CIRCUIT LOW VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Condition for setting DTC

1. Engine running.
2. TP sensor reads less than .20 volt for 6.25 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off (throttle closed). 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. Disconnect TP sensor connector. Connect a jumper wire between signal circuit and 5-volt reference circuit terminals at TP sensor harness connector. 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. Connect a test light between battery voltage 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 replacing sensor, go to step 12).
11. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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 P0122. 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).
13. 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 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 - 2.4L 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.

Conditions for setting DTC are as follows

1. Engine running.
2. TP sensor voltage is greater than 3.9 volts for 14 seconds.
3. MAP less than 60 kPa.
4. Engine speed less than 1500 RPM.
5. DTC P0107 or P0108 not set.

Or

1. TP sensor voltage is greater than 4.8 volts.
2. DTCs P0107 or P0108 not set.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 one volt, go to step 4). If voltage is not greater than one 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. Disconnect TP sensor connector. Observe TP sensor voltage. If voltage is less than .3 volt, go to next step. If voltage is not less than .3 volt, go to step 6).
5. Connect a test light between battery voltage and sensor ground circuit terminal at TP sensor connector. If test light illuminates, go to step 7). If test light does not illuminate, go to step 9).
6. Check for short to voltage in signal circuit. Repair as necessary. After repairs, go to step 12). If circuit is okay, go to step 11).
7. Check for short to 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 11).
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 replacing sensor, go to step 12).
11. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
12. Using scan tool, select CLEAR INFO or CLEAR DTCS function to 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 TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST 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.

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.

DTC P0125 - ECT EXCESSIVE TIME TO REACH CLOSED LOOP

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Fuel delivery system will operate in open loop when engine coolant temperature is less than 68°F (20°C). During open loop, PCM ignores oxygen sensor signal and calculates air/fuel ratio based on inputs from Engine Coolant Temperature (ECT) sensor, Throttle Position (TP) sensor and Manifold Absolute Pressure (MAP) sensor.

Conditions for setting this DTC are as follows

1. ECT less than 113°F (40°C) .
2. Engine run time is greater than 6 minutes.
3. System in "open-loop".
4. DTC(s) P0112, P0113, P0117 or P0118 not set.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Allow engine to cool to ambient temperature. Turn ignition on, with engine off. Using scan tool, compare ECT sensor temperature reading to IAT sensor temperature sensor reading. If readings are close to each other, go to step 4). If readings are not close to each other, go to next step.
3. Disconnect ECT sensor connector. Using DVOM, check ECT sensor resistance. See «ECT TEMPERATURE-TO-RESISTANCE VALUES»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l) table. If ECT resistance value is close as indicated, go to next step. If ECT resistance value is not as specified, go to step 10).
4. Disconnect ECT sensor connector. If scan tool indicates ECT sensor temperature is less than -22°F (-30°C), go to next step. If scan tool indicates ECT sensor temperature is -22°F (-30°C) or greater, go to step 8).
5. Connect a jumper wire between signal circuit and sensor ground circuit terminals at ECT sensor harness connector. If scan tool 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 7).
6. Check cooling system for proper operation. Repair as necessary. After repairs, go to step 11). If cooling system is functioning properly, see DIAGNOSTIC AIDS.
7. Disconnect and inspect ECT sensor and PCM connectors. Repair connectors as necessary. After repairs, go to step 11). If connectors are okay, go to step 9).
8. Check ECT sensor signal circuit for short to ground. Repair as necessary. After repairs, go to step 11). If circuit is okay, go to next step.
9. Turn ignition off. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 11).
10. Replace ECT sensor. After replacing sensor, 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 DTC P0125. 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.

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.

DTC P0131 - O2S CIRCUIT LOW VOLTAGE SENSOR 1

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 will set.

Conditions for setting this DTC

1. DTCs P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300, P0301, P0302, P0303, P0304, P0404, P0405, P0506, P0507, P1404, or P1441 not set.
2. Airflow greater than 3 gms/s.
3. ECT greater than 158°F (70°C).
4. Engine in "closed-loop".
5. TP sensor angle is 8-50 percent.
6. Engine has met above conditions for 20 seconds.
7. O2S 1 voltage is less than 52 mV for greater than 2 minutes.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Ensure engine is at normal operating temperature. Turn ignition on, with engine off. Using scan tool, observe O2S 1 voltage. If voltage stays at less than 44 mV, go to next step. If voltage does not stay at less than 44 mV, go to step 7).
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 stays at less than 44 mV, go to next step. If voltage does not stay at less than 44 mV, 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, see DIAGNOSTIC AIDS. If voltage is not 407-509 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. Turn ignition off. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
7. 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 P0131. 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).
8. 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.

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 CIRCUIT HIGH VOLTAGE SENSOR 1

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 will set.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Airflow greater than 3 gm/s.
3. ECT greater than 158°F (70°C).
4. TP sensor angle is 5-50 percent.
5. Engine is in closed loop.
6. O2S 1 voltage is greater than 1042 mV for 50 seconds.
7. O2S 1 voltage is greater than 738 mV in deceleration mode for 50 seconds.
8. Conditions met for 30 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Ensure engine is at normal operating temperature. Turn ignition on, with engine off. Using scan tool, observe O2S 1 sensor voltage. If voltage stays at greater than 1042 mV, go to step 4). If voltage does not stay at greater than 1042 mV, 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 stays at greater than 1042 mV, go to next step. If voltage does not stay at greater than 1042 mV, go to step 8).
4. Disconnect O2S 1 connector. Connect a jumper wire between ground and O2S 1 harness connector. Observe O2S 1 voltage. If voltage is less than 600 mV, see DIAGNOSTIC AIDS. If voltage is not less than 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 replacing PCM, go to next step.
7. 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 P0132. 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).
8. 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.

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 SYSTEM/COMPONENT TESTS - 2.4L 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 SYSTEM/COMPONENT TESTS - 2.4L article.

DTC P0133 - O2S SLOW RESPONSE SENSOR 1

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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, a DTC P0133 will set.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Engine speed is 1600-2600 RPM.
3. TP sensor angle is 8-20 percent.
4. Ratio of response times is greater than 3.5 or less than .4.
5. Purge learned memory is greater than 191.
6. Evaporative emission control system is commanded open for greater than 36 percent Pulse Width Modulated (PWM).
7. Conditions present for greater than 100 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. Start engine. Ensure engine is at normal operating temperature. Operate vehicle within the conditions required for setting this DTC. Using scan tool, monitor the following: LEAN/RICH AVG. (ms). RICH/LEAN AVG. (ms). RICH/LEAN to LEAN/RICH RATIO SEN. 1 (greater than, less than). If average values are less than 249 ms, 249 ms, or ratios greater than 3.5, 0.4, go to next step. If average values are not less than 249 ms, 249 ms, or ratios are not greater than 3.5, 0.4, go to next step.
4. Inspect the following: Check for proper O2S 1 installation. Check O2S 1 connector and wiring for corrosion or damage. Check O2S 1 ground circuit. 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 repair is completed, 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 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. 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 repair is completed, 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 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 connectors. Check resistance between ground and O2S 1 ground circuit terminal 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 than 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 DTC P0133. 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, no problem is indicated at this time.

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 SYSTEM/COMPONENT TESTS - 2.4L 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 SYSTEM/COMPONENT TESTS - 2.4L article.

DTC P0134 - O2S INSUFFICIENT ACTIVITY SENSOR 1

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 near .45 volt for an extended period, DTC will set.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Airflow greater than 3 gm/s.
3. ECT greater than 158°F (70°C).
4. Engine run time is greater than 30 seconds.
5. TP sensor angle is 4-56 percent for 20 seconds.
6. O2S 1 voltage is 399-499 mV for 125 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 next step. If scan tool does not indicate closed loop, go to step 12).
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 in step 6) 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 replacing PCM, go to next step.
9. Replace oxygen sensor. After replacing sensor, 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. 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 P0134. 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).
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 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 P0137 - HO2S CIRCUIT VOLTAGE LOW SENSOR 2

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Airflow greater than 5.5 gm/s.
3. ECT greater than 104°F (40°C).
4. TP sensor angle is 5-50 percent for 4 seconds.
5. HO2S 2 voltage is less than 22 mV for 150 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. Disconnect HO2S 2 connector. Connect a jumper wire between ground and ground circuit terminal at HO2S harness connector. 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 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 and program replacement PCM. PCM requires special equipment for programming procedures. After replacing PCM, go to step 8).
7. Replace oxygen sensor. After replacing sensor, 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 DTC P0137. 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.

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 CIRCUIT VOLTAGE HIGH SENSOR 2

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Airflow greater than 5.5 gm/s.
3. ECT greater than 104°F (40°C).
4. TP sensor angle is 5-50 percent for 4 seconds.
5. HO2S 2 voltage is greater than 1042 mV for 50-75 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 connector. Disconnect PCM connectors. Using a DVOM, check 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 connectors. Turn ignition on, engine off. Connect a jumper wire between ground and sensor ground circuit and signal circuit terminals at HO2S 2 harness connector. 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 oxygen sensor. After replacing sensor, go to step 9).
8. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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 DTC P0138. 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, no problem is indicated at this time.

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.

DTC P0140 - HO2S INSUFFICIENT ACTIVITY SENSOR 2

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0171, P0200, P0300, P0301, P0302, P0303, P0304, P0341, P0404, P0506, P0507, P0601 or P0602 not set.
2. Airflow greater than 5.5 gm/s.
3. ECT greater than 104°F (40°C).
4. TP sensor angle is 4-56 percent.
5. HO2S 2 voltage is 425-460 mV for 125 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 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 connector. Connect a jumper wire between ground and sensor 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 and reconnect HO2S 2 connector. Disconnect PCM connector. Connect a test light between battery voltage terminal and sensor ground circuit terminal at PCM harness connector. If test light illuminates, go to step 8). If test light does not illuminate, go to step 9).
7. Replace oxygen sensor. After replacing sensor, go to step 11).
8. Check HO2S 2 signal circuit for 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 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 DTC P0140. 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.

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 HEATER CIRCUIT SENSOR 2

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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).

Conditions for setting this DTC

1. ECT and IAT less than 113°F (45°C).
2. Difference between ECT and IAT is less than 45°F (7°C).
3. TP angle is less than 20 percent.
4. HO2S voltage increases, decreases or is less than 150 mV in 100-190 seconds (based on start-up coolant temperature).

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 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 blown, go to step 8). If fuse is okay, go to step 9).
6. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair terminals as necessary. After repairs, go to step 13). If connector is okay, go to step 10).
7. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair terminals 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 wiring as necessary. After repairs, replace fuse and go to step 13).
9. Inspect HO2S 2 harness connector for faulty terminals or poor connection. Repair terminals as necessary. After repairs, go to step 13).
10. Replace oxygen sensor. After replacing sensor, go to next step.
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, 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 P0141. 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).
14. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

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. DTC will set if PCM detects an excessively lean condition.

Conditions for setting DTC

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 not set.
2. IAT -13 to 175°F (-25 to 115°C).
3. ECT 140-239°F (60-115°C).
4. Engine speed is 550-3400 RPM (A/T).
5. Vehicle speed is less than 70 MPH.
6. MAP greater than 27 kPa.
7. BARO greater than 73.8 kPa.
8. EVAP purge is not occurring.
9. Fuel trim index is greater than 160.
10. Conditions present for longer than 4 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 165, go to next step. If fuel trim index is greater than specified, 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 165, go to step 16). If fuel trim index is greater than specification, 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 connector. Operate vehicle in closed loop while monitoring FUEL INDEX TRIM. If fuel trim index is less than 165, go to step 16). If fuel trim index is greater than specification, 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 165, go to next step. If fuel trim index is greater than 165, go to step 9).
8. Lean condition is not present at this time. If a driveability problem exists, go to TESTS W/O CODES - 2.4L 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 repairs are necessary, 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 5 or less, 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. Go to 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 41-47 psi (284-325 kPa), go to next step. If fuel pressure is not 41-47 psi (284-325 kPa), repair fuel system as necessary. See SYSTEM/COMPONENT TESTS - 2.4L 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 SYSTEM/COMPONENT TESTS - 2.4L article. If fuel pressure is not as specified, see BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 2.4L article.
15. Replace MAP sensor. After repair is completed, go to next step.
16. 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 P0171. 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).
17. 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.

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 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.

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, P0200, P0300, P0301, P0302, P0303, P0304, P0325, P0335, P0341, P0342, P0401, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0602, P1404, P1133 or P1441 not set.
2. IAT -13 to 175°F (-25 to 115°C).
3. ECT 140-239°F (60-115°C).
4. Vehicle speed is less than 70 MPH.
5. Engine speed is 750-3400 RPM.
6. Fuel trim index is less than 80.
7. EVAP purge is not occurring.
8. Conditions present for 16 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 75, go to step 5). If fuel trim index is not less than 75, 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 less than 75, go to step 21). If fuel trim index is not less than 75, 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 not, 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 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 60, go to step 20). If fuel trim index is not greater than 60, go to next step.
12. Go to DTC P0506 or P0507 to check IAC valve performance. 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. Perform BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 2.4L 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 SYSTEM/COMPONENT TESTS - 2.4L 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 FUEL SYSTEM in SYSTEM/COMPONENT TESTS - 2.4L 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.
19. Check Throttle Position (TP) sensor mounting screws. Tighten or replace screws as necessary. After repair is completed, go to step 21). If mounting screws are okay, replace TP sensor. After replacing sensor, go to step 21).
20. Replace MAP sensor. After replacing sensor, go to next step.
21. 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 P0172. 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).
22. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

Disconnect and inspect PCM 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 P0200 - INJECTOR CONTROL CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 4-amps to quickly open injectors. Current is then reduced to one amp to keep injector open. If current cannot reach 4-amps or injector driver is shorted to voltage, DTC P0200 will set.

Conditions for setting this DTC are as follows

1. Injector current less than 4 amps.
2. Battery voltage greater than 9 volts.
3. Conditions met for 5 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Attempt to start engine. If engine starts, go to next step. If engine will not start, go to NO START DIAGNOSIS in BASIC TESTING - 2.4L article.
3. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Start engine and allow engine to idle for one minute. If DTC P0220 resets, go to step 5). If DTC P0220 does not reset, 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 DTC P0220 resets, go to next step. If DTC P0220 does not reset, go to step 16).
5. Turn ignition off. Remove air cleaner outlet resonator. Disconnect all injector connectors. Install an injector test light at No. 1 injector harness connector. Crank engine and observe test light. Check remaining fuel injectors. If test light flashes for all injectors, perform INJECTOR BALANCE TEST. See FUEL SYSTEM in SYSTEM/COMPONENT TESTS - 2.4L article. If test light does not flash at all injectors, go to next step.
6. If test light did not flash in step 5) but was on steady, go to next step. If test light did not flash in step 5) and was off, go to step 10).
7. Disconnect PCM connectors. With test light connected to positive battery terminal, probe affected injector driver circuits. If test light illuminates, go to next step. If test light does not illuminate, go to step 9).
8. Repair short to ground in injector driver circuit. After repairs, go to step 16).
9. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 16).
10. With test light connected to ground, probe ignition feed circuit terminal at affected injector harness connector. Crank engine. If test light illuminates, go to next step. If test light does not illuminate, go to step 12).
11. With test light still connected to ground, probe injector driver circuit terminal at affected injector harness connector. Crank engine. If test light does not illuminate, go to step 13). If test light illuminates, go to step 14).
12. Repair open in injection feed circuit. After repairs, go to step 16).
13. Check for open or faulty connection in injector driver circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 9).
14. Repair short to voltage in injector driver circuit. After repairs, go to step 16).
15. Repair open or faulty connection in injector driver circuit. After repairs, go to next step.
16. 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).
17. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, no problem is indicated at this time.

An injector that is shorted to voltage or is disconnected while engine is operating will cause a DTC P0200 to set. A misfire related DTC should also be set indicating which cylinder is inoperative.

DTC P0300 - ENGINE MISFIRE DETECTED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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, 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 469-6400 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 changed more than 8 percent in one second.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0200 is also set, diagnose DTC as necessary 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 repair is completed, go to step 26). 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 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 26).
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. If fuel pressure is 31-44 psi (2.2-3.1 kg/cm 2 ), go to next step. If fuel pressure is not 31-44 psi (2.2-3.1 kg/cm 2 ), see BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 2.4L 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 repair is completed, go to step 26).
10. Replace contaminated fuel. After repair is completed, go to step 26).
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 13).
12. Check for faulty spark plugs. Replace defective spark plug(s) as necessary. After repairs, go to step 26). If spark plugs are okay, go to step 9).
13. Turn ignition off. Remove boot assemblies from affected ignition coil. Using a DVOM, measure secondary resistance of coil. If resistance is less than 10,000 ohms, go to next step. If resistance is not less than 10,000 ohms, go to step 15).
14. Remove ignition coil housing. Disconnect coil harness connector at ICM. Connect a test light between positive battery terminal and coil driver circuit terminal at ICM that did not have spark. Crank engine and observe test light. If test light flashes, go to step 16). If test light does not flash, go to step 17).
15. Remove ignition coil from ignition coil housing. Recheck secondary resistance of coil. If resistance is less than 10,000 ohms, go to step 18). If resistance is not less than 10,000 ohms, go to step 19).
16. Repair open or shorted ignition coil wiring harness, poor ignition coil connector or replace ignition coil, ignition coil housing or boot assembly. After repairs, go to step 26).
17. Disconnect and inspect ICM 11-pin connector. Repair as necessary. After repairs, go to step 26). If connector is okay, go to step 20).
18. Replace ignition coil springs for affected cylinder. After repairs, go to step 26).
19. Replace suspect coil. After repairs, go to step 26).
20. Turn ignition off. Disconnect ICM 11-pin connector. Check resistance between ground and each ignition control circuit terminal at ICM harness connector. If both resistances are 600-2600 ohms, go to next step. If either resistance is not 600-2600 ohms, go to step 22).
21. Replace ICM module. After replacing module, go to step 26).
22. Disconnect and inspect PCM connector terminals. If connector is not okay, go to step 24). If connector is okay, go to next step.
23. Check for an open or short in ignition control circuit(s). Repair as necessary. After repairs, go to step 26). If circuits are okay, go to step 25).
24. Repair connector terminals. After repairs, go to step 26).
25. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
26. 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 TEST RAN AND PASSED, go to next step. If scan tool does not indicate TEST RAN AND PASSED, repeat step 2).
27. 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 TESTS W/O CODES - 2.4L article for intermittent diagnosis.

DTC P0301 - CYLINDER NO. 1 MISFIRE DETECTED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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, P0401, P0404, P0405, P0502, P0503, P0506, P0507, P0601, P0740, P0742, P1133, P1404 or P1621 not set.
2. Misfire total is greater than 12 counts.
3. Engine speed is 469-6400 RPM.
4. Battery voltage 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. Engine run time greater than 5 seconds.
7. TP sensor angle has not changed more than 8 percent in one second.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0200 is also set, diagnose DTC as necessary 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 22). 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. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) on spark plug jumper for cylinder No. 1. Remove spark plug boot from cylinder No. 4 at ignition coil housing. Connect a jumper wire between ground and spark plug connector at ignition coil housing (where No. 4 spark plug boot was). With remaining spark plug boots still connected, crank engine and check for spark. If spark is present, go to step 7). If spark is not present, 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 22).
7. 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 a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 22).
9. Replace defective spark plug. After repairs, go to step 22).
10. Turn ignition off. Remove boot assemblies from affected ignition coil. Using a DVOM, measure secondary resistance of coil. If resistance is less than 10,000 ohms, go to next step. If resistance is not less than 10,000 ohms, go to step 12).
11. Remove ignition coil housing. Disconnect coil harness connector at ICM. Connect a test light between positive battery terminal and No. 1 and 4 ignition coil driver circuit terminal at ICM. Crank engine and observe test light. If test light flashes, go to step 13). If test light does not flash, go to step 14).
12. Remove ignition coil from ignition coil housing. Recheck secondary resistance of coil. If resistance is less than 10,000 ohms, go to step 15). If resistance is not less than 10,000 ohms, go to step 16).
13. Repair open or shorted ignition coil wiring harness, poor ignition coil connector or replace ignition coil, ignition coil housing or boot assembly. After repairs, go to step 22).
14. Disconnect and inspect ICM 11-pin connector. Repair as necessary. After repairs, go to step 22). If connector is okay, go to step 17).
15. Replace ignition coil springs for cylinders No. 1 and 4 coil. After repairs, go to step 22).
16. Replace ignition coil for cylinders No. 1 and 4. After repairs, go to step 22).
17. Turn ignition off. Disconnect ICM 11-pin connector. Check resistance between ground and each ignition control circuit terminal at ICM harness connector. If all resistances are 600-2600 ohms, go to step 19). If any of the resistance measurements is not 600-2600 ohms, go to next step.
18. Check for an open or short in ignition control circuit(s). Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 20).
19. Replace ICM module. After replacing module, go to step 22).
20. Disconnect and inspect PCM connector terminals. Repair as necessary. After repairs, go to step 22). If connector is okay, go to next step.
21. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
22. 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).
23. 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 TESTS W/O CODES - 2.4L article for intermittent diagnosis.

DTC P0302 - CYLINDER NO. 2 MISFIRE DETECTED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 469-6400 RPM.
4. Battery voltage is 9-17 volts.
5. ECT 20-254°F (-7 to 123°C).
6. Engine run time greater than 5 seconds.
7. TP sensor angle has not changed more than 8 percent in one second.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0200 is also set, diagnose DTC as necessary 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 22). 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. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) on spark plug jumper for cylinder No. 2. Remove spark plug boot from cylinder No. 3 at ignition coil housing. Connect a jumper wire between ground and spark plug connector at ignition coil housing (where No. 3 spark plug boot was). With remaining spark plug boots still connected, crank engine and check for spark. If spark is present, go to step 7). If spark is not present, 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 22).
7. 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, go to next step. If MISFIRE CURRENT NO. 2 counter is not incrementing, go to step 9).
8. Check for a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 22).
9. Replace defective spark plug. After repairs, go to step 22).
10. Turn ignition off. Remove boot assemblies from affected ignition coil. Using a DVOM, check secondary resistance of coil. If resistance is less than 10,000 ohms, go to next step. If resistance is not less than 10,000 ohms, go to step 12).
11. Remove ignition coil housing. Disconnect coil harness connector at ICM. Connect a test light between positive battery terminal and No. 2 and No. 3 ignition coil driver circuit terminal at ICM. Observe test light and crank engine. If test light flashes, go to step 13). If test light does not flash, go to step 14).
12. Remove ignition coil from ignition coil housing. Recheck secondary resistance of coil. If resistance is less than 10,000 ohms, go to step 15). If resistance is not less than 10,000 ohms, go to step 16).
13. Repair open or shorted ignition coil wiring harness, poor ignition coil connector or replace ignition coil, ignition coil housing or boot assembly. After repairs, go to step 22).
14. Disconnect and inspect ICM 11-pin connector. Repair as necessary. After repairs, go to step 22). If connector is okay, go to step 17).
15. Replace ignition coil springs for cylinders No. 2 and 3 coil. After repair is completed, go to step 22).
16. Replace ignition coil for cylinders No. 2 and 3. After repairs, go to step 22).
17. Turn ignition off. Disconnect ICM 11-pin connector. Measure resistance between ground and each ignition control circuit terminal at ICM harness connector. If both resistances are 600-2600 ohms, go to step 19). If any resistance is not 600-2600 ohms, go to next step.
18. Check for an open or short in ignition control circuit(s). Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 20).
19. Replace ICM module. After replacing module, go to step 22).
20. Disconnect and inspect PCM connector terminals. Repair as necessary. After repairs, go to step 22). If connector is okay, go to next step.
21. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
22. 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).
23. 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 TESTS W/O CODES - 2.4L article for intermittent diagnosis.

DTC P0303 - CYLINDER NO. 3 MISFIRE DETECTED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 469-6400 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 5 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0200 is also set, diagnose DTC as necessary 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 22). 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. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) on spark plug jumper for cylinder No. 3. Remove spark plug boot from cylinder No. 2 at ignition coil housing. Connect a jumper wire between ground and spark plug connector at ignition coil housing (where No. 2 spark plug boot was). With remaining spark plug boots still connected, crank engine and check for spark. If spark is present, go to step 7). If spark is not present, 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 22).
7. 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 a basic engine problem (compression, cam timing, throttle body leak, restricted airflow, etc.). Repair as necessary. After repairs, go to step 22).
9. Replace defective spark plug. After repairs, go to step 22).
10. Turn ignition off. Remove boot assemblies from affected ignition coil. Using a DVOM, measure secondary resistance of coil. If resistance is less than 10,000 ohms, go to next step. If resistance is not less than 10,000 ohms, go to step 12).
11. Remove ignition coil housing. Disconnect coil harness connector at ICM. Connect a test light between positive battery terminal and No. 2 and 3 ignition coil driver circuit terminal at ICM. Observe test light and crank engine. If test light flashes, go to step 13). If test light does not flash, go to step 14).
12. Remove ignition coil from ignition coil housing. Recheck secondary resistance of coil. If resistance is less than 10,000 ohms, go to step 15). If resistance is not less than 10,000 ohms, go to step 16).
13. Repair open or shorted ignition coil wiring harness, poor ignition coil connector or replace ignition coil, ignition coil housing or boot assembly. After repairs, go to step 22).
14. Disconnect and inspect ICM 11-pin harness connector. Repair connector as necessary. After repairs, go to step 22). If connector is okay, go to step 17).
15. Replace ignition coil springs for cylinders No. 2 and 3 coil. After repairs, go to step 22).
16. Replace ignition coil for cylinders No. 2 and 3. After repairs, go to step 22).
17. Turn ignition off. Disconnect ICM 11-pin connector. Measure resistance between ground and each ignition control circuit terminal at ICM harness connector. If both resistances are 600-2600 ohms, go to step 19). If any resistance is not 600-2600 ohms, go to next step.
18. Check for an open or short in ignition control circuit(s). Repair as necessary. After repair is completed, go to step 22). If circuits are okay, go to step 20).
19. Replace ICM. After repair is completed, go to step 22).
20. Disconnect and inspect PCM connector terminals. Repair as necessary. After repairs, go to step 22). If connector is okay, go to next step.
21. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
22. 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).
23. 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 TESTS W/O CODES - 2.4L article for intermittent diagnosis.

DTC P0304 - CYLINDER NO. 4 MISFIRE DETECTED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 469-6400 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 greater than 15 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0200 is also set, diagnose that DTC as necessary 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 repair is completed, go to step 22). 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. Temporarily remove ignition coil and Ignition Control Module (ICM) assembly. Install Spark Plug Jumper Wires (J-36012). Install Spark Tester (J-26792) on spark plug jumper for cylinder No. 4. Remove spark plug boot from cylinder No. 1 at ignition coil housing. Connect a jumper wire between ground and spark plug connector at ignition coil housing (where No. 1 spark plug boot was). With remaining spark plug boots still connected, crank engine and check for spark. If spark is present, go to step 7). If spark is not present, 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. 4 counter is not incrementing, go to step 22).
7. 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 a basic engine problem (compression, cam timing, throttle body leak, restricted air flow. etc.). Repair as necessary. After repairs, go to step 22).
9. Replace defective spark plug. After repair is completed, go to step 22).
10. Turn ignition off. Remove boot assemblies from affected ignition coil. Using a DVOM, measure secondary resistance of coil. If resistance is less than 10,000 ohms, go to next step. If resistance is not less than 10,000 ohms, go to step 12).
11. Remove ignition coil housing. Disconnect coil harness connector at ICM. Connect a test light between positive battery terminal and No. 1 and 4 ignition coil driver circuit terminal at ICM. Crank engine and observe test light. If test light flashes, go to step 13). If test light does not flash, go to step 14).
12. Remove ignition coil from ignition coil housing. Recheck secondary resistance of coil. If resistance is less than 10,000 ohms, go to step 15). If resistance is not less than 10,000 ohms, go to step 16).
13. Repair open or shorted ignition coil wiring harness, poor ignition coil connector or replace ignition coil, ignition coil housing or boot assembly. After repairs, go to step 22).
14. Disconnect and inspect ICM 11-pin harness connector. Repair connector as necessary. After repairs, go to step 22). If connector is okay, go to step 17).
15. Replace ignition coil springs for cylinders No. 1 and 4 coil. After repairs, go to step 22).
16. Replace ignition coil for cylinders No. 1 and 4. After repairs, go to step 22).
17. Turn ignition off. Disconnect ICM 11-pin connector. Measure resistance between ground and each ignition control circuit terminal at ICM harness connector. If both resistances are 600-2600 ohms, go to step 19). If any resistance is not 600-2600 ohms, go to next step.
18. Check for an open or short in ignition control circuit(s). Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 20).
19. Replace ICM. After repair is completed, go to step 22).
20. Disconnect and inspect PCM connector terminals. Repair as necessary. After repairs, go to step 22). If connector is okay, go to next step.
21. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
22. 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).
23. 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 TESTS W/O CODES - 2.4L article for intermittent diagnosis.

DTC P0325 - KNOCK SENSOR CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 90-110 k/ohms, go to next step. If resistance is not 90-110 k/ohms, 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

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If engine will not start, go to NO START DIAGNOSIS in BASIC TESTING - 2.4L 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. 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 P0341 - CAMSHAFT POSITION (CMP) SENSOR CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 P0342 - CAMSHAFT POSITION SENSOR CIRCUIT LOW

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. If CMP ACTIVITY counter is incrementing, go to step 16). If CMP ACTIVITY counter is not incrementing, go to next step.
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. With test light connected to positive battery terminal, probe 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. Check for poor connection at CMP feed circuit at PCM connector. Repair as necessary. After repairs, go to step 16). If connection is okay, go to step 15).
7. Reconnect CMP harness sensor connector. Turn ignition off. Disconnect PCM C2 harness connector. Connect a jumper wire between positive battery terminal and ignition feed circuit terminal at PCM C2 harness connector. With DVOM connected to ground, probe CMP signal circuit terminal at PCM connector. If voltage varies from zero volts to battery voltage, go to step 15). If voltage does not vary from zero volts to battery voltage, go to step 9).
8. Check for poor connection or open in CMP ground circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 15).
9. If DVOM reading in step 7) is a constant voltage (either zero or battery voltage), go to next step. If voltage reading is not a constant voltage, go to step 11).
10. Check for a short to voltage in CMP signal circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to step 14).
11. Disconnect CMP sensor connector. With DVOM connected to positive battery terminal, probe CMP signal circuit terminal at CMP sensor harness connector. If voltage is greater than .5 volt, go to next step. If voltage is not greater than .5 volt, go to step 13).
12. Repair short to ground in CMP signal circuit. After repairs, go to step 16).
13. Check for poor connection or an open in CMP signal circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to next step.
14. Replace CMP sensor. After replacing sensor, go to step 16).
15. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
16. 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 P0342. 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).
17. 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 P0401 - EGR SYSTEM INSUFFICIENT FLOW

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A linear Exhaust Gas Recirculation (EGR) valve is used on this system. Powertrain Control Module (PCM) commands EGR valve to operate when necessary by controlling a ground signal through PCM. This can be monitored on a scan tool by selecting DESIRED EGR POSITION function. Ignition voltage is supplied to EGR valve thorough a fuse. PCM monitors results of its command through a feedback signal. Feedback signal is the actual position of the EGR pintle. This feedback signal can also be monitored on a scan tool by selecting ACTUAL EGR POSITION function. The ACTUAL EGR POSITION should always be near the commanded or DESIRED EGR POSITION.

Conditions for setting this DTC are as follows

1. DTC(s) P0106, P0107, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0200, P0300-P0304, P0335, P0502, P0506, P0507 and P1441 not set.
2. Engine speed is 900-1700 RPM (A/T).
3. Engine speed is 1000-2200 RPM (M/T).
4. ECT greater than 167°F (75°C).
5. BARO greater than 72 kPa.
6. MAP is 12-32 kPa.
7. TP angle less than one percent.
8. Vehicle speed is greater than 20 MPH.
9. EGR flow restricted.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Start engine and allow it to idle. Using scan tool, command EGR valve to 50 percent. If engine stalls or runs rough, go to step 5). If engine does not stall or run rough, go to next step.
3. Turn ignition off. Remove EGR valve. Inspect EGR valve, passages and pipe for restriction or damage. Repair as necessary. After repairs, go to step 5). If no problems are found, go to next step.
4. Replace EGR valve. After repairs, go to next step.
5. Disconnect negative battery cable for 10 seconds, then reconnect cable. Road test vehicle. Increase vehicle speed to 60 MPH, then release accelerator and allow vehicle to decelerate to 20 MPH. If Decel Exponentially Weighted Moving Average (EWMA) value is not greater than zero, return to step 3). If EWMA is greater than zero, go to next step. NOTE: For more information on Decel EWMA, see DIAGNOSTIC AIDS.
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 P0401. 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.

Decel Exponentially Weighted Moving Average (EWMA) value is an average of the difference in expected MAP change and actual MAP change caused by opening EGR valve during deceleration. By driving vehicle to 60 MPH and decelerating to 20 MPH, it can be determined if EGR system is okay, partially restricted or fully restricted.

A negative number; less than -3 indicates system is functioning properly. A positive number indicates system is fully restricted and the expected amount of EGR flow is incorrect. A number that falls between -3 and +2 indicates system is partially restricted. The Decel EWMA value should always be -3 or less. If value becomes more positive, check for damaged EGR pipe, restricted EGR passage or defective EGR valve.

DTC P0404 - EGR VALVE PINTLE POSITION OPEN

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A linear EGR is used to accurately supply exhaust gasses to engine without the use of intake manifold vacuum. EGR is controlled by the PCM using inputs from TP and MAP sensors. PCM monitors the results of its command through a feedback signal. By sending a 5-volt reference and ground to EGR, a voltage signal representing the EGR valve pintle position is sent to PCM. This feedback signal can also be monitored on scan tool and is the actual position of EGR pintle. The actual EGR position should always be near the commanded or desired EGR position.

Conditions for setting DTC

1. DTC(s) 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. EGR commanded on (desired EGR position greater than zero percent).
4. Actual EGR position differs from desired EGR position by greater than 9 percent for 18 seconds.

1. Perform Powertrain On-Board Diagnostic (OBD) System Check. After performing OBD system check, go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EGR valve to 25, 50, 75, 100 percent. If actual EGR position follow the desired EGR position, go to step 19). If actual EGR position does not follow the desired EGR position, go to next step.
3. Disconnect EGR harness connector. Using a test light connected to battery voltage, probe EGR valve harness connector ground circuit. If test light illuminates, go to next step. If test light does not illuminate, go to step 5).
4. Connect test light to ground. Probe EGR harness connector control circuit. Using scan tool, command EGR to 25, 50, 75, 100 percent. If test light flash, maintain a steady glow or illuminates and gets brighter as command is raised, go to step 6). If test light does not flash or maintain a steady glow, or does not illuminate, go to step 7).
5. Repair open or poor connection in EGR ground circuit. After repairs, go to step 19).
6. With test light still connected to ground, probe EGR signal circuit. If test light illuminates, go to step 8). If test light does not illuminate, go to step 9).
7. With test light still connected to ground, probe EGR control circuit without commanding EGR with scan tool. If test light illuminates, go to step 10). If test light does not illuminate, go to step 11).
8. Check signal circuit for short to voltage. Repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 12).
9. Using a DVOM connected to ground, probe 5-volt reference circuit. If voltage reading is about 5 volts, go to step 13). If voltage reading is not about 5 volts, go to step 14).
10. Check control circuit for short to voltage. Repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 12).
11. Connect test light to battery voltage and probe EGR control circuit. If test light illuminates, go to step 15). If test light does not illuminate, go to step 16).
12. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 19).
13. Check EGR ground circuit for poor connection or proper terminal tension at PCM and repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 17).
14. Check 5-volt reference circuit for short to voltage and repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 12).
15. Check control circuit for short to ground. Repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 12).
16. Check control circuit for an open or poor connection at EGR harness connector. Repair as necessary. After repairs, go to step 19). If circuit is okay, go to step 18).
17. Replace EGR valve. After replacing EGR, go to step 19).
18. Check for poor connection at PCM harness connector. Repair as necessary. After repairs, go to next step. If connection is okay, go to step 12).
19. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2).
20. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test.

Due to moisture in exhaust system, EGR valve may sometimes freeze and stick in colder weather. Problem may disappear after vehicle is brought into a warm shop for repairs. By using scan tool and watching actual EGR and desired EGR positions on a cold engine, fault can be easily verified. Check FREEZE FRAME data to determine if DTC set when vehicle was cold by viewing ECT.

DTC P0405 - EGR VALVE SENSOR SIGNAL LOW

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A linear EGR is used to accurately supply exhaust gasses to engine without the use of intake manifold vacuum. EGR is controlled by the PCM using inputs from TP and MAP sensors. PCM monitors the results of its command through a feedback signal. By sending a 5-volt reference and ground to EGR, a voltage signal representing the EGR valve pintle position is sent to PCM. This feedback signal can also be monitored on scan tool and is the actual position of EGR pintle. The actual EGR position should always be near the commanded or desired EGR position.

Conditions for setting DTC

1. DTC(s) P0106, P0107, 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. EGR commanded ON (desired EGR position greater than zero percent).
4. Actual EGR position differs from desired EGR position by greater than 9 percent for 11 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EGR valve to 25, 50, 75, 100 percent. If actual EGR position follow the desired EGR position, go to step 15). If actual EGR position does not follow the desired EGR position, go to next step.
3. Disconnect EGR harness connector. Using DVOM connected to ground, probe EGR valve harness connector 5-volt reference circuit. If DVOM reads about 5 volts, go to next step. If DVOM does not read about 5 volts, go to step 5).
4. Using a jumper wire, jumper EGR 5-volt reference circuit to signal circuit. If actual EGR position display is 100 percent, go to step 6). If display is not 100 percent, go to step 7).
5. Using a test light connected to battery voltage, probe EGR 5-volt reference circuit. If test light illuminates, go to step 8). If test light does not illuminate, go to step 9).
6. Check 5-volt reference and signal circuits for poor connection or proper terminal tension. Repair as necessary. After repairs, go to step 15). If circuits are okay, go to step 10).
7. Using test light connected to battery voltage, probe EGR signal circuit. If test light illuminates, go to step 11). If test light does not illuminate, go to step 12).
8. Check for short to ground in EGR 5-volt reference circuit. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 13).
9. Check for open in EGR 5-volt reference circuit. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 14).
10. Replace EGR valve. After replacing EGR, go to step 15).
11. Check for short to ground in EGR signal circuit. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 13).
12. Check for open in EGR signal circuit. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 14).
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 15).
14. Check affected circuit for poor connection or proper terminal tension at PCM. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 13).
15. Using scan tool, select DTC, CLEAR INFO function. Start and warm engine to normal operating temperature. Select DTC, SPECIFIC, then enter DTC P0404. Operate vehicle within conditions for setting this DTC. If scan tool indicates that this test ran and passed, go to next step. If scan tool did not indicate that this test ran and passed, repeat step 2).
16. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. Diagnostic Aids - Due to moisture in exhaust system, EGR valve may sometimes freeze and stick in colder weather. Problem may disappear after vehicle is brought into a warm shop for repairs. By using scan tool and watching actual EGR and desired EGR positions on a cold engine, fault can be easily verified. Check FREEZE FRAME data to determine if DTC set when vehicle was cold by viewing ECT.

A 3-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 3-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. DTC(s) 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 .11 volt from EGR sensor.
4. Malfunction present for 25 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 click, go to next step. If purge valve and/or vent solenoid do 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 0 mm Hg, go to step 7). If scan tool does not read 0 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 is released, 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. 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 - 2.4L 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. DTC(s) 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 SYSTEM/COMPONENT TESTS - 2.4L 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 0 mm Hg, go to step 6). If fuel tank pressure is not 0 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 PO452 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). Turn 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.
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 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 SYSTEM CANISTER VENT BLOCKED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

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. DTC(s) 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 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 9-35 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. If DTC P0452, P0453 or P0460 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, go to next step. If purge and/or vent solenoid does not click, perform PCM diagnosis. See SYSTEM/COMPONENT TESTS - 2.4L 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 0 mm Hg, go to step 6). If fuel tank pressure is not 0 mm Hg, go to next step.
5. Check EVAP purge line from fuel tank to EVAP canister for pinched, kinked or plugged line. Repair or replace 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 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 PO452 or P0453 diagnostic tests.
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 0 in. H2O within 5 seconds, see DIAGNOSTIC AIDS. If EVAP pressure return line is not 0 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. 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 step 12).
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 DTC(s). 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 LOW VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 between 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. 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 HIGH VOLTAGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 between 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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.
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 P0460 - FUEL LEVEL SENSOR CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Powertrain Control Module (PCM) uses fuel level input from the instrument panel cluster to calculate expected vapor pressures within fuel system. Vapor pressure varies as fuel level changes.

Conditions for setting this DTC are as follows

1. Fuel level has not changed greater than 1.6 percent (4 counts) in 120 miles.
2. DTC P1601 or P1610 is set and vehicle has been driven for greater than 120 miles.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Check if DTC U1016 or U1064 is also set. If DTC U1016 or U1064 is set, diagnose affected DTC(s) first. If no other DTCs are set, go to next step.
3. Diagnose instrument cluster. After diagnosing instrument cluster, go to next step.
4. Verify repairs by viewing scan tool fuel level data. If fuel level data reflects the correct amount of fuel in the tank, go to next step. If fuel level data does not reflect correct amount of fuel in fuel tank, repeat step 2).
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.

When DTC P0460 is set and an EVAP system DTC is also set, the EVAP DTC cannot be considered valid until DTC P0460 is repaired and cleared.

DTC P0480 - COOLING FAN RELAY NO. 1 CONTROL CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

The cooling fan is controlled by the Body Function Controller (BFC). BFC sends a Class II 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.

Conditions for setting DTC

1. PCM detects that commanded state of driver and actual state of control circuit do not match.
2. Condition present for at least 6 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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. 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

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

The cooling fan is controlled by the Body Function Controller (BFC). BFC sends a Class II 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.

Conditions for setting DTC

1. PCM detects that commanded state of driver and actual state of control circuit do not match.
2. Condition present for at least 6 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 fro 2 minutes. If current draw is less than .75 amp, but not less than zero, see DIAGNOSTIC AIDS. If current draw is not less than .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 P0506 - IAC SYSTEM RPM LOW

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 more than 19 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 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. Measure 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 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 repair is completed, 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.

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 P0507 - IAC SYSTEM RPM HIGH

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 more than 5 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 turns on for 2 terminals, go to next step. If test light does not turn on for 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 turns on for 2 terminals, go to step 8). If test light does not turn on for 2 terminals, go to step 9).
7. Check for an open or short to ground in IAC valve lo 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 repair is completed, 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.

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

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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 .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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) . Store FREEZE FRAME and FAILURE RECORDS data for conditions which set code. 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 greater than 279 psi (3.0 volts), go to next step. If high side value is not greater than 279 psi (3.0 volts), go to step 10).
4. 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 6).
5. 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 7). If voltage reading is not greater than 0.5 volt, go to step 8).
6. 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).
7. 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).
8. Replace A/C refrigerant pressure sensor. After replacing sensor, go to step 10).
9. Replace PCM. Prior to replacement, check PCM terminals, connectors and wiring harness for damage. After replacing PCM, go to next step.
10. Clear DTCs. Start engine and idle to normal operating temperature. Operate vehicle within conditions which set code. If scan tool indicates this code diagnostic has ran and passed, go to next step. If scan does not indicate that test ran and passed, repeat step 2).
11. Check if additional DTCs are set. Diagnose affected DTCs. If no additional DTCs are set, system is okay. See DIAGNOSTIC AIDS.

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 - 2.4L 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 is less than 10 volts, go to next step. If voltage 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 is greater than 12 volts, go to next step. If voltage 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 is greater than 10 volts, go to next step. If voltage 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.

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 - 2.4L 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.

Condition for setting DTC

1. System voltage greater than 17 volts.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 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 is less than 17 volts, go to next step. If voltage 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. 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.

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.

Condition for setting this DTC is as follows

1. PCM detects more than 3 incorrect checksums.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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.

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

1. PCM recognizes an invalid PRNDL parameter.
2. Vehicle speed greater than 5 MPH.
3. Conditions met for a period longer than 5 seconds.

Transaxle Range Switch Valid Input Combination Values. Scheme 1

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check), then 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 1) 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 1) 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.

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 INSUFFICIENT SWITCHING SENSOR 1

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Conditions for setting this DTC

1. 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.
2. Engine speed 1600-2600 RPM.
3. TP sensor angle 9-20 percent.
4. EVAP emission control system commanded open for greater than 36 percent Pulse Width Modulated (PWM).
5. Purge learned memory greater than 191.
6. Conditions present for at least 100 seconds.
7. Number of rich-to-lean counts less than 10 or lean-to-rich counts less than 15.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 30-40 on A/T or 10-15 on M/T vehicles, go to next step. If transition is not 30-40 on A/T or 10-15 on M/T vehicles, go to step 18).
4. Inspect the following: Check for proper O2S 1 installation. Check O2S 1 connector and wiring for corrosion or damage. 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 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. If voltage is less than 200 mV, go to next step. If voltage 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 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. Disconnect PCM 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 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 DTC P1133. 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.

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 SYSTEM/COMPONENT TESTS - 2.4L 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 SYSTEM/COMPONENT TESTS - 2.4L 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, a DTC P1171 will set.

Conditions for setting DTC

1. DTCs P0131, P0132, P0133, P0134 and P1133 not set.
2. ECT greater than 70°F (20°C).
3. Engine running longer than 20 seconds.
4. Engine in "closed-loop".
5. O2S 1 voltage is less than 300 mV for 5 seconds.
6. Engine is in power enrichment mode.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 more than 447 mV (during power enrichment mode). If voltage is as specified, go to BASIC FUEL SYSTEM CHECKS in BASIC TESTING - 2.4L article. If voltage is not as specified, go to DTC P0134 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.

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 - 2.4L 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.

Conditions for setting DTC

1. Crankshaft position system variation values are not stored in the PCM memory.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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.

PCM detects engine misfire by detecting variations in crankshaft deceleration between firing strokes. For accurate detection of engine misfire, PCM must be able to distinguish between crankshaft deceleration caused by actual misfire or deceleration caused by rough road conditions.

The ABS system can detect if vehicle is on a rough road based on wheel acceleration/deceleration data supplied by the wheel speed sensors. If ABS system detects rough road above a predetermined threshold, this information is sent to the PCM via the serial data (UART). PCM can then take the rough road into account when calculating misfire. Even if the ABS is malfunctioning and cannot detect rough roads, the misfire diagnostic will continue to run. However, if a misfire DTC is set, this additional DTC P1380 will also set indicating that rough road data was not available during the misfire calculation due to ABS system malfunction.

Conditions for setting this DTC are as follows

1. DTC P0300-P0304 not set.
2. Vehicle speed greater than one MPH.
3. Engine speed is less than 3406 RPM.
4. PCM received no ABS information for 2.5 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off. Using scan tool, attempt to display ABS data. If ABS data can be displayed, go to next step. If ABS data cannot be displayed, go to step 4).
3. Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. 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 a misfire DTC set, go to step 5). If a misfire DTC did not set, go to step 9).
4. Repair condition causing ABS data not to be displayed. See ANTI-LOCK BRAKE SYSTEM article in BRAKES section. After repairs, go to step 3).
5. If DTC P1381 also set, go to next step. If DTC P1381 did not set, go to step 7).
6. If ABS data can be displayed, go to step 8). If ABS data cannot be displayed, go to step 4).
7. Repair condition causing misfire as necessary. After repair is completed, go to step 9).
8. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, 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.

Setting of this DTC indicates that a misfire was detected and that the PCM could not determine if fault was a true misfire or due to operating vehicle on a rough surface. A misfire can be a true misfire with or without setting this DTC. Check Electronic Brake Control Module (EBCM) for poor connections at serial data (UART) terminals.

DTC P1404 - EGR VALVE CLOSED PINTLE POSITION

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A linear Exhaust Gas Recirculation (EGR) valve is used on this system. Powertrain Control Module (PCM) commands EGR valve to operate when necessary by controlling a ground signal through PCM. This can be monitored on a scan tool by selecting DESIRED EGR POSITION function. Ignition voltage is supplied to EGR valve thorough a fuse. PCM monitors results of its command through a feedback signal. Feedback signal is the actual position of the EGR pintle. This feedback signal can also be monitored on a scan tool by selecting ACTUAL EGR POSITION function. The ACTUAL EGR POSITION should always be near the commanded or DESIRED EGR POSITION.

Conditions for setting this DTC are as follows

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0200, P0300-P0304, P0335, P0440, P0442, P0446, P0502, P0507, P1336 and P1441 not set.
2. Ignition voltage greater than 11.7 volts.
3. EGR commanded off (desired EGR position is 0 percent).
4. Actual EGR position is greater than 15 percent for 20 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, with engine off. Using scan tool, command EGR valve to 0, 20, 50, 70 and 100 percent. If ACTUAL EGR POSITION follows the DESIRED EGR POSITION, go to step 13). If ACTUAL EGR POSITION does not follow the DESIRED EGR POSITION, go to next step.
3. Disconnect EGR valve connector. If ACTUAL EGR POSITION is near 100 percent, go to next step. If ACTUAL EGR POSITION is not near 100 percent, go to step 5).
4. Check signal circuit for short to voltage. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 6).
5. Using DVOM connected to ground, probe EGR 5-volt reference circuit terminal at EGR harness connector. If voltage reading is 5 volts, go to step 7). If voltage reading is not 5 volts, go to step 8).
6. Replace PCM. Program replacement PCM using required equipment. After repair is completed, go to step 15).
7. Using a test light connected to ground, probe EGR ignition feed terminal at harness connector. If test light illuminates, go to step 9). If test light does not illuminate, go to step 10).
8. Check EGR valve 5-volt reference circuit for short to voltage. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 6).
9. Check EGR ignition feed circuit for short to voltage. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 6).
10. Connect test light between battery voltage and EGR sensor ground circuit terminal. If test light illuminates, go to next step. If test light does not illuminate, go to step 12).
11. Check EGR sensor ground circuit for open or poor connection at EGR harness connector. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 13).
12. Check for open in EGR sensor ground circuit. Repair as necessary. After repairs, go to step 15). If circuit is okay, go to step 14).
13. Replace EGR valve. After replacing EGR, go to step 15).
14. Check PCM harness connector for poor connection. Repair as necessary. After repairs, go to next step. If connections are okay, go to step 6).
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 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).
16. If any other DTCs are set, diagnose DTCs as necessary. If no other DTCs are set, system is okay. See DIAGNOSTIC AIDS.

Moisture in exhaust system may cause EGR valve to freeze or stick in colder weather. After vehicle is brought into a warm shop for repairs, EGR valve warms and the problem goes away. By watching ACTUAL EGR POSITION and DESIRED EGR POSITION on a cold vehicle with a scan tool. View FREEZE FRAME data to determine if DTC set when vehicle was cold by viewing ENGINE COOLANT TEMPERATURE and INTAKE AIR TEMPERATURE.

DTC P1441 - EVAP SYSTEM FLOW DURING NON-PURGE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L 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.

Conditions for setting this DTC are as follows

1. BARO greater than 75 kPa.
2. IAT 41-84°F (5-29°C).
3. ECT 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 2°F (1°C) of IAT at engine start-up.
6. Fuel tank level is 26-74 percent.
7. TP sensor is 7-35 percent.
8. EVAP solenoid is at 50 percent PWM within 65 seconds of engine run time.
9. EVAP unable to detect vacuum during diagnostic test.
10. DTCs P0106, P0107, P108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0131, P0132, P0133, P0134 and P1133 not set.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 SYSTEM/COMPONENT TESTS - 2.4L 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 0 mm Hg, go to step 6). If fuel tank pressure sensor value is not 0 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 or P0453 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.
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 0 in. H2O or greater, go to next step. If fuel tank pressure value is not 0 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).

Condition for setting DTC

1. PCM cannot communicate internally.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then 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 - LOSS OF SERIAL COMMUNICATION WITH VEHICLE THEFT DETERRENT OR THEFT DETERRENT SYSTEM FUEL ENABLE CIRCUIT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A Class II 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 II 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.

Conditions for setting this DTC

1. PCM has lost communication with Body Function Controller (BFC) after PCM received a theft passed message from BFC.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Using scan tool, check if DTC U1064 is also set. If DTC U1064 is set, diagnose DTC U1064 first. If DTC U1064 is not set, go to next step.
3. Check if any of vehicle theft deterrent system have been tampered with. If theft deterrent system have been tampered, go to next step. If no components were tampered, go to step 5).
4. Repair tampered components. After repairs, perform PASS-Lock(R) password learn procedure. After performing learn procedure, go to step 8).
5. If Body Function Controller (BFC) indicates that password is valid, go to next step. If BFC indicates that password is not valid, go to step 7).
6. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
7. Check for BFC related DTCs. Diagnose DTC as necessary. After repairs, 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 FAIL 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 PCM IN LEARN MODE

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Vehicle Theft Deterrent (VTD) system disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Function Controller (BFC) and PCM.

When starting engine, PCM looks for a password from the BFC through the Class II 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).

Conditions for setting DTC

1. Pass-Lock(R) II password learn procedure has been interrupted or ready to learn.
2. PCM received an incorrect password.
3. PCM finished the 10 minute learn pending timer (ignition on for 10 minutes).

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
2. Perform Password Learn Procedure. See ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. Attempt to start engine. If engine starts and continues to run, go to step 5). If engine does not start or starts and then stalls, go to next step.
3. Check if VTD components has been recently replaced. If components has been replaced, repeat step 2). If components has not been replaced recently, go to next step.
4. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
5. 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).
6. 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, P1626 and P1631 may set. PCM must be reflashed to allow new password to be learned if BFC is replaced. Turn ignition off for at least 30 seconds then on for PCM to learn the new BFC password.

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

DTC P1631 - THEFT DETERRENT SYSTEM PASSWORD INCORRECT

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Vehicle Theft Deterrent (VTD) system disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Function Controller (BFC) or Truck Body Controller (TBC) and PCM.

When starting engine, PCM looks for a password from the BFC or TBC through the Class II 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).

Conditions for setting DTC

1. Unrecognized or incorrect password sent to PCM from BFC or TBC.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
2. Using scan tool, display data list for BFC or TBC. If scan tool indicates that Pass-Lock(R) data is valid, go to next step. If scan tool does not indicate that Pass-Lock(R) data is valid, go to step 4).
3. Perform Password Learn Procedure. See ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. Attempt to start engine. If engine starts and continues to run, go to step 7). If engine does not start or starts and then stalls, go to step 6).
4. Check if any theft deterrent related DTCs are set. Diagnose affected DTCs. If theft deterrent related DTCS are not set, go to next step.
5. Diagnose theft deterrent system. Refer to ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section.
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 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 P1631 and P1632 may set. PCM must be reflashed to allow new password to be learned if BFC or TBC 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 SYSTEM FUEL DISABLED

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

Vehicle Theft Deterrent (VTD) system disables engine unless the lock cylinder is correctly engaged by a mechanical key. VTD system includes lock cylinder, ignition switch, Body Function Controller (BFC) or Truck Body Controller (TBC) and PCM.

When starting engine, PCM looks for a password from the BFC or TBC through the Class II 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).

Conditions for setting DTC

1. Unrecognized or incorrect password sent to PCM from BFC or TBC.
2. Undecided password sent from BFC or TBC.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) . Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. After performing OBD system check, go to next step.
2. Using scan tool, check if DTCs P1626, P1630 or P1631 is also set. Diagnose affected DTC(s). If DTCs are not set, go to next step.
3. Perform Password Learn Procedure. See ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. Attempt to start engine. If engine starts and continues to run, go to step 8). If engine does not start or starts and then stalls, go to next step.
4. Using scan tool, display data list for BFC or TBC (trucks). If scan tool indicates that Pass-Lock(R) data is valid, go to next step. If scan tool does not indicate that Pass-Lock(R) data is valid, go to step 6).
5. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 8).
6. Check if there are any theft deterrent related DTCs set. Diagnose affected DTCs. If no theft deterrent related DTCs are set, go to next step.
7. Diagnose theft deterrent system. See ANTI-THEFT SYSTEM article in ACCESSORIES/SAFETY EQUIPMENT section. After repairs, go to next step.
8. 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).
9. 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 BFC or TBC 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 U1000 - NO CLASS II COMMUNICATION (ID NOT LEARNED)

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A Class II serial data communications system is used to allow various modules to communicate and share information with each other. If a module cannot respond to PCM, DTC is set.

Conditions for setting DTC

1. PCM cannot communicate with EBCM, BFC or TBC during the initial 15 seconds after ignition is turned on. PCM cannot determine if the EBTCM, BFC or TBC modules are functioning properly.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, engine off. Using scan tool, check if data from PCM can be displayed. If scan tool can display PCM data, go to next step. If scan tool cannot display PCM data, diagnose Data Link Connector (DLC). See see WIRING DIAGRAMS - 2.4L article.
3. Using scan tool, attempt to communicate with EBCM. If scan tool can communicate with EBCM, go to next step. If scan tool cannot communicate with EBCM, diagnose electrical system. See see WIRING DIAGRAMS - 2.4L article.
4. Using scan tool, attempt to communicate with BFC or TBC (trucks). If scan tool can communicate with BFC or TBC, go to next step. If scan tool cannot communicate with BFC or TBC, diagnose electrical system. See see WIRING DIAGRAMS - 2.4L article.
5. Using scan tool, check for additional DTCs or communication with other modules. Diagnose or repair as necessary. After repairs, go to next step.
6. 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).
7. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay. See DIAGNOSTIC AIDS.

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

DTC U1016 - SERIAL COMMUNICATIONS MALFUNCTION

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

UART serial data communications system is used to allow various modules to communicate and share information with each other. the serial data communication circuit is connected to 4 components or modules

1. Powertrain Control Module (PCM)
2. Diagnostic Energy Reserve Module (DERM)
3. Electronic Brake Control Module (EBCM)
4. Instrument Panel Cluster (IPC)

The IPC is the master of this network and sends out an updated information and requests from other modules through the serial data circuit. Each module responds back to the IPC with updated information. PCM communicates with EBCM through the IPC over the serial data circuit. DTC will set if any of the modules cannot respond to each other.

Conditions for setting this DTC

1. PCM does not receive 25 valid responses from IPC.
2. System voltage greater than 6.8 volts.
3. Conditions met for 10 seconds.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Turn ignition on, engine off. Observe instrument panel and check if COOLANT indicator light is illuminated. If indicator light is illuminates, go to next step. If indicator light is not illuminates, go to step 9).
3. Using scan tool, check if scan tool can communicate with IPC. If scan tool communicates with IPC, go to next step. If scan tool cannot communicate with IPC, go to step 5).
4. Check for open in UART serial data circuit. Repair as necessary. After repairs, go to step 9). If circuit is okay, go to step 6).
5. Check for short to ground or voltage in UART serial data circuit. Repair as necessary. After repairs, go to step 9). If circuit is okay, go to step 7).
6. Check for poor connection at PCM connector. Repair as necessary. After repairs, go to step 9). If connections are okay, go to step 8).
7. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Using scan tool, attempt to communicate with IPC. If scan tool communicates with IPC, go to next step. If scan tool cannot communicate with IPC, diagnose DLC circuit. See WIRING DIAGRAMS - 2.4L article.
8. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to step 9).
9. Using scan tool, clear DTCs. Start and warm engine to normal operating temperature. Operate vehicle within conditions required for setting this DTC. If scan tool indicates that this diagnostic has ran and passed, go to next step. If scan tool does not indicate that this diagnostic has 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.

Move PCM and IPC connectors wile watching IPC to see if serial data is lost. When serial data is lost, IPC indicator lights will illuminate, a good indication that serial data is lost to IPC.

Check for intermittent problem caused by electrical interference on ground circuit of IPC, a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Check for faulty or damaged terminal connections. Install an additional ground from IPC to battery negative terminal if electrical interference is suspected.

DTC U1040 - LOSS OF EBCM/EBTCM COMMUNICATION

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A Class II serial data communications system is used to allow various modules to communicate and share information with each other. If a module cannot respond to PCM, DTC is set.

Conditions for setting DTC

1. PCM does not receive identifier message from EBCM.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Using scan tool, check if scan tool can display data from PCM. If scan tool can display data from PCM, go to next step. If scan tool cannot display data from PCM, diagnose DLC circuit. See WIRING DIAGRAMS - 2.4L article.
3. Check for intermittent short or open in serial data circuit to EBCM. Repair as necessary. After repairs, go to step 6). If circuit is okay, go to next step.
4. Check for intermittent short or open in serial data circuit to BFC. Repair as necessary. After repairs, go to step 6). If circuit is okay, go to next step.
5. Using scan tool, check for additional DTCs or communication with other modules. Diagnose or repair as necessary. After repairs, go to next step.
6. 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).
7. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay. See DIAGNOSTIC AIDS.

Attempting to start vehicle by by-passing Pass-Lock(R) II system or by substituting parts without performing the password learn procedure any set DTC P1631 and P1632.

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

DTC U1041 - LOSS OF EBCM COMMUNICATION

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A Class II serial data communications system is used to allow various modules to communicate and share information with each other. If a module cannot respond to PCM, DTC is set.

Conditions for setting DTC

1. PCM cannot communicate with EBCM for 15 seconds after having previously established communications with EBCM within that ignition cycle.
2. Ignition switch in CRANK position for 15 seconds and engine not rotating due to a starter or starting system malfunction, or clutch pedal not depressed on M/T vehicles.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Using scan tool, check if scan tool can display data from PCM. If scan tool can display data from PCM, go to next step. If scan tool cannot display data from PCM, diagnose DLC circuit. See WIRING DIAGRAMS - 2.4L article.
3. Using scan tool, check if scan tool can display EBCM data. If scan tool can display EBCM data, go to next step. If scan tool cannot display EBCM data, diagnose electrical system. See WIRING DIAGRAMS - 2.4L article.
4. Check for intermittent short or open in serial data circuit to BFC. Repair as necessary. After repairs, go to step 6). If circuit is okay, go to next step.
5. Using scan tool, check for additional DTCs or communication with other modules. Diagnose or repair as necessary. After repairs, go to next step.
6. 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).
7. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay. See DIAGNOSTIC AIDS.

Check for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Install additional ground wire from IPC to negative side of battery terminal if electrical interference is suspected.

DTC U1064 - LOSS OF BCM/TBC/VTD COMMUNICATION

Note. For circuit reference, see WIRING DIAGRAMS - 2.4L article.

A Class II serial data communications system is used to allow various modules to communicate and share information with each other. If a module cannot respond to PCM, DTC is set.

Conditions for setting DTC

1. PCM cannot communicate with BCM, TBC or VTD for 15 seconds after having previously established communications with BCM, TBC or VTD within that ignition cycle.

1. Perform «POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK»(/chevrolet/malibu/v-1996-2000/remont/testing-diagnostics/#engine-controls-tests-wcodes-24l__powertrain-on-board-diagnostic-obd-system-check) , then go to next step.
2. Using scan tool, check if scan tool can display data from PCM. If scan tool can display data from PCM, go to next step. If scan tool cannot display data from PCM, diagnose DLC circuit. See WIRING DIAGRAMS - 2.4L article.
3. Using scan tool, check if scan tool can display BCM, TBC or VTD data. If scan tool can display data, go to next step. If scan tool cannot display data, diagnose electrical system. See WIRING DIAGRAMS - 2.4L article.
4. Check for intermittent short or open in serial data circuit to BFC. Repair as necessary. After repairs, go to step 6). If circuit is okay, go to next step.
5. Using scan tool, check for additional DTCs or communication with other modules. Diagnose or repair as necessary. After repairs, go to next step.
6. 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).
7. Check for additional DTCs. If additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, system is okay. See DIAGNOSTIC AIDS.

Check for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire inside insulation. Install additional ground wire from IPC to negative side of battery terminal if electrical interference is suspected.

See also:
• DIAGNOSTIC PROCEDURE
• POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK
• HARD OR INTERMITTENT TROUBLE CODE DETERMINATION
• TROUBLE CODE DEFINITION
• P0106
• P0107
• P0108
• P0112
• P0113
• P0117
• P0118
• P0121
• P0122
• P0123
• P0125
• P0131
• P0132
• P0133
• P0134
• P0137
• P0138
• P0140
• P0141
• P0200
• P0300
• P0301
• P0302
• P0303
• P0304
• P0325
• P0335
• P0341
• P0342
• P0404
• P0405
• P0440
• P0442
• P0446
• P0452
• P0453
• P0460
• P0480
• P0506
• P0507
• P0530
• P0562
• P0563
• P1133
• P1336
• P1404
• P1441
• P1630
• P1631
• P1632
• U1000
• U1016
• U1040
• U1064
• CLEARING DIAGNOSTIC TROUBLE CODES (DTC)