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Home >> Chevrolet >> 2001 >> Cavalier LS, 2.2 4 >> Repair and Diagnosis >> External Pages >> Different car >> Section 36 (Engine Controls Self-Diagnostics - 2.4L) >> Diagnostic Tests >> DTC P0301-P0304: Engine Misfire Detected >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire and 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform diagnostic system check - engine controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM. After performing diagnostic system check - engine controls, go to next step.
  2. Turn ignition on, with engine off. Install a scan tool. Are any injector DTCs set? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, go to next step.
  3. Turn ignition off. Perform a visual and physical inspection. Make any necessary repairs. Were any repairs necessary? If yes, go to step  25 . If no, go to next step.
  4. Start and idle engine. Observe the Misfire Current Counters with the scan tool. Is the Misfire Current #1 counter incrementing? If yes, go to next step. If no, go to step  6 .
  5. Turn ignition off. Remove air cleaner outlet resonator assembly. Disconnect all fuel injector electrical connectors. Disconnect the IC module 11-pin electrical connector. Temporarily remove the ignition coil and the electronic IC module assembly. Reconnect the IC module 11-pin electrical connector. Install the J-36012-A Ignition System Diagnostic Harness into spark plug boot assemblies. Install J-26792 Spark Plug tester on the spark plug jumper wire for the affected cylinder spark plug. Remove spark plug boot assembly from companion cylinder of ignition coil housing. Install a jumper wire from the companion spark plug connector of ignition coil housing to ground. Connect a jumper wire to the IC module assembly to ground. Crank engine with remaining spark plug wires still connected. Does spark tester spark? If yes, go to step  7 . If no, go to step  10 .
  6. Turn ignition on, with engine off. Review the Freeze Frame data and record the parameters. Start the engine. Operate the vehicle within the Freeze Frame conditions and Conditions For Running the DTC. See CONDITIONS FOR RUNNING DTC  . Observe the Misfire Current Counters with the scan tool. Is the Misfire Current counter for the affected cylinder incrementing? If yes, go to step  5 . If no, go to step  25 .
  7. Turn ignition off. Remove the spark plug from the affected cylinder. Exchange the spark plug with a spark plug from a known-good cylinder. Reconnect all the fuel injector electrical connectors. Install the spark plug boot assembly to the affected cylinder spark plug connection at the ignition coil housing. Reconnect the spark plug jumper wire to the spark plug boot assembly. Start the engine. Run the vehicle when the misfire was present. Is the Misfire Current for the affected cylinder counter incrementing? If yes, go to next step. If no, go to step  9 .
  8. Check for a leaking fuel injector. Refer to DTC P0201-P0204: INJECTOR CONTROL CIRCUIT  starting at step 5)  of DTC P0201-P0204. If the fuel injector is okay, check for a basic engine problem. Did you find and correct the condition? If yes, go to step  25 .
  9. Turn ignition off. Replace the spark plug. After repairs, go to step  25 .
  10. Turn ignition off. Remove the spark plug boot assemblies from the affected coil. Disconnect the IC module 11-pin electrical connector. Connect a Digital Multimeter (DMM) between the secondary ignition coil terminals at the ignition coil housing. Is the resistance between 4-8 k/ohms? If yes, go to next step. If no, go to step  12 .
  11. Remove the coil housing. Disconnect the coil harness electrical connector from the IC module. Reconnect the IC module 11-pin electrical connector. Connect a test light to B+. Probe the affected cylinder coil control terminal with the test light. Crank the engine while watching the test light. Does the test light blink? If yes, go to step  13 . If no, go to step  14 .
  12. Remove the affected cylinder ignition coil from the ignition coil housing. Recheck the resistance between the secondary terminals of the affected cylinder ignition coil. Is the resistance between 4-8 k/ohms? If yes, go to step  15 . If no, go to step  16 .
  13. Remove ignition coils from ignition coil housing. Carefully handle ignition coils electrical connectors to avoid spark arching from electrical terminals and causing fuse to open which would lead to misdiagnosis. Disconnect ignition coil electrical connector from ignition coils. Reconnect ignition coil electrical connector to IC module. Connect a test light to ground. Turn ignition on, with engine off. Probe ignition feed circuit to ignition coils at both of ignition coil electrical connector terminal "B" with test light. Does the test light illuminate for both circuits? If yes, go to step  19 . If no, go to step  20 .
  14. Turn ignition off. Disconnect IC module 11-pin electrical connector. Visually and physically inspect IC module 11-pin electrical connector to see if the electrical connections are clean and tight. Make any necessary repairs. Did you find and correct the condition? If yes, go to step  25 . If no, go to step  17 .
  15. Check and replace ignition coil spring for affected coils or ignition coil housing, as necessary. When complete, go to step  25 .
  16. Replace the affected cylinders ignition coil. When complete, go to step  25 .
  17. Reconnect IC module 11-pin electrical connector. Disconnect PCM electrical connector C1. Reconnect affected cylinder spark plug boot assembly to spark plug connector at ignition coil housing. Reconnect spark plug jumper wire to affected cylinder spark plug boot assembly. Reconnect J-26792 on affected cylinder spark plug wire. Connect a jumper wire to companion cylinder spark plug connector at ignition coil housing to ground. Turn ignition on, with engine off. Connect a test light to B+. DO NOT leave test light connected to PCM IC circuit connector for longer than 5 seconds at a time. Failure to do so may damage ignition coil and/or the IC module. Momentarily touch the IC timing control circuit for the affected cylinder at PCM electrical connector. A spark should be present when test light is removed from the IC timing control circuit. Is there a spark present when you remove test light from IC timing control circuit? If yes, go to step  23 . If no, go to next step.
  18. Turn ignition off. Check for the following conditions in the IC timing control circuit: An open circuit, short to ground, short to B+, or poor electrical connection at IC module. Repair the circuit as necessary. Were any repairs necessary? If yes, go to step  25 . If no, go to step  22 .
  19. Check the affected cylinder coil control circuit for poor electrical connection to the IC module and ignition coil, an open circuit, short to ground or short to voltage. Repair circuit as necessary. Was a repair necessary? If yes, go to step  25 . If no, go to step  21 .
  20. Turn ignition off. Repair open in the ignition positive voltage circuit between the No. 1-4 and No. 2-3 ignition coils electrical connectors. After repairs, go to step  25 .
  21. Turn ignition off. Check ignition positive voltage circuit for a poor electrical connection at the ignition affected cylinder ignition coil. If electrical connection is okay, replace spark plug boot assembly. After repairs, go to step  25 .
  22. Turn ignition off. Replace the IC module. When complete, go to step  25 .
  23. Turn ignition off. Inspect the PCM electrical connector and connections. Repair the electrical connector and the connections as necessary. Did you find and correct the condition? If yes, go to step  25 . If no, go to next step.
  24. Replace PCM. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  25. Reconnect all previously disconnected components, if not already reconnected. Connect all the fuel injector electrical connectors. Install the air cleaner outlet resonator assembly. Clear DTCs with scan tool. Start engine. Idle the engine at normal operating temperature. Operate vehicle within the Conditions for Running this DTC and P0420. Does the scan tool indicate that these diagnostics have ran and passed? If yes, go to next step. If no, go to step  2 .
  26. Turn ignition on, with engine off. Using scan tool, observe the stored information and Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no, system is okay.
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