LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 335 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0300: Engine 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. Did you perform the Diagnostic System Check - Engine Controls? If yes, go to next step. If no, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS .
  2. Start the 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? go to step 3 If no, problem is intermittent. Refer to INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.2L & 3.0L VUE article.
  3. Are any DTCs other than DTC P0300 set? If yes, go to 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. Disconnect the harness connector of the affected ignition module assemblies. The fuel injector test light will be dim, which is normal. If using a different fuel injector test light, the bulb resistance must be 4 ohms or less. Using jumper wires, connect the Fuel Injector Test Light (J-34730-2C) between the ignition voltage circuit and the affected cylinder Ignition Control (IC) 1 of the ignition module harness connector. Command the affected cylinder ignition coil ON with a scan tool. Does the fuel injector test light flash? If yes, go to step  7. If no, go to next step.
  6. Perform the fuel injector coil test. Refer to FUEL INJECTOR COIL TEST under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 2.2L & 3.0L VUE article. Did you find and correct the condition? If yes, go to next step. If no, diagnose for an engine mechanical problem.
  7. Was the customer's concern about the Malfunction Indicator Light (MIL) flashing? If yes, go to next step. If no, go to step  9.
  8. Operate the vehicle at 2500 RPM for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0421 or P0431. Refer to DTC P0421 OR P0431: WARM-UP CATALYST - BELOW THRESHOLD . Does the DTC run and pass? If yes, go to next step. If no, go to DTC P0421 OR P0431: WARM-UP CATALYST - BELOW THRESHOLD .
  9. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions for Running the DTC. See CONDITIONS FOR RUNNING DTC . You may also operate the vehicle within the conditions that you 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.
  10. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, diagnose affected DTC(s). See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no DTCs are displayed, system is okay.
scientia non olet · About LEMON Manuals