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Home >> Chevrolet >> 2001 >> Venture Base, Van Passenger >> Repair and Diagnosis >> External Pages >> Different car >> Section 180 (Engine Controls - Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0301-P0304: Cylinders No. 1-4 Misfire Detected >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Saturn Vue. 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. Start engine. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the misfire counters with the scan tool. Are any of the misfire current counters incrementing? If yes, go to next step. If no, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L & 3.0L VUE article.
  3. Are any DTCs other than DTC P0300 set? If yes, diagnose affected DTC(s). See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  4. Can any abnormal engine noise be heard? If yes, diagnose engine mechanical problem. If no, go to next step.
  5. Turn ignition off. Remove the fuel pump relay. DO NOT remove the IC module and connector from the ignition coil housing. Remove ignition coil housing assembly. Connect a jumper wire between the IC module and a good ground. Install Ignition System Diagnostic Harness (J-36012-A). Install Spark Tester (J-26792) on the affected cylinder spark plug jumper wire. Ground the companion to the affected cylinder spark plug jumper wire. Crank the engine with the remaining spark plug jumper wires connected. Does the spark tester spark? If yes, go to step  7. If no, go to next step.
  6. Inspect the affected cylinder spark plug boot for a missing or damaged ignition coil spring. Did you find and correct the condition? If yes, go to step  16. If no, go to step  15.
  7. Remove the spark plug from the cylinder that indicated a misfire. Inspect the spark plug. Does the spark plug appear to be okay? If yes, go to next step. If no, go to step  9.
  8. Exchange the suspected spark plug with another cylinder that is operating properly. Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug? If yes, go to step  14. If no, go to step  12.
  9. Is the spark plug oil or coolant fouled? If yes, diagnose for an engine mechanical problem. If no, go to next step.
  10. Is the spark plug gas fouled? If yes, go to step  12. If no, go to next step.
  11. Does the spark plug show any signs of being cracked, worn, or improperly gapped? If yes, go to step  13. If no, go to next step.
  12. Perform the fuel injector coil test. Refer to FUEL INJECTOR COIL TEST in SYSTEM & COMPONENT TESTING - 2.2L & 3.0L VUE article. Did you find and correct the condition? If yes, go to step  16. If no, diagnose for an engine mechanical problem.
  13. Replace or gap the spark plug. If an improper gap is found, be sure to gap the spark plugs using a wire type gauge. After regapping spark plug, go to step  16.
  14. Replace faulty spark plug. After replacing spark plug, go to step  16.
  15. Replace ignition coil housing. After replacing ignition coil housing, go to next step.
  16. Was the customer concern the MIL flashing? If yes, go to next step. If no, go to step  18.
  17. Operate engine at 2500 RPM for 4 minutes. Operate the vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . Does the DTC run and pass? If yes, go to next step. If no, go to DTC P0420: CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD .
  18. Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Operate vehicle within the conditions for running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate vehicle within the conditions observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  19. With a scan tool, observe the stored information, Capture Info. Does the scan tool display any DTCs that you have not diagnosed? If yes, see DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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