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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 108 (Engine Controls Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0301-P0304: Cylinder Misfire Detected (DOHC) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Pontiac Sunfire, 2002 Pontiac Grand Am, 2002 Oldsmobile Alero, 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 scan tool. Are DTCs P0201, P0202, P0203, or P0204 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  10. If no, go to next step.
  4. Turn ignition on, with engine off. Review the Freeze Frame data and record the parameters. Start 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 next step. If no, go to DIAGNOSTIC AIDS .
  5. Turn ignition off. Remove fuel pump relay. DO NOT remove ICM and connector from ignition coil housing. Remove ignition coil housing assembly. Not grounding ignition coil housing may cause erratic spark. Connect a jumper wire between ICM and a good ground. Install the J-36012-A Ignition System Diagnostic Harness. Install a J-26792 Spark Tester on the affected cylinder spark plug jumper wire. Ground the companion to the affected cylinder spark plug jumper wire. Crank engine with remaining spark plug jumper wires connected. Does the spark tester spark? If yes, go to next step. If no, go to step  8.
  6. Inspect for missing or damaged ignition coil spring for the affected cylinder. Remove the affected cylinder spark plug. Inspect for a malfunctioning spark plug. Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
  7. Perform injector coil test and injector balance test procedure. See INJECTOR COIL TEST and INJECTOR BALANCE TEST in appropriate SYSTEM & COMPONENT TESTING article. Did you find and correct the condition? If yes, go to step  10. If no, diagnose for engine mechanical problem.
  8. Turn ignition off. Remove the spark plug boots from the affected coil. Inspect the affected cylinder boot for damage or missing spring, and replace as necessary. Did you find and correct the condition? If yes, go to step  10. If no, go to next step.
  9. Replace ignition coil housing. When complete, go to next step.
  10. Reconnect all previously disconnected components (if not already reconnected). Connect all the fuel injector electrical connectors. Install the air cleaner outlet resonator assembly. Use the scan tool in order to clear the DTCs. Start engine. Idle the engine at the normal operating temperature. Operate the vehicle within the Conditions for Running this DTC and DTC P0420. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  11. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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