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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 81 (Engine Controls - Self-Diagnostics - 8.1L) >> Diagnostic Tests >> DTC P0351-P0358: Ignition Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

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  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
    2. NOTE: If all of the Ignition Control (IC) DTCs are set at the same time, inspect the IC ground circuits and the battery voltage circuits for an open.
  2. Connect a scan tool. Start the engine. Monitor the IC status for the cylinder with the ignition control DTC using the scan tool. Does the scan tool indicate Fault? If yes, go to step  4. If no, go to next step.
  3. Observe the Freeze Frame/Failure Records data for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC, or as closely as possible to the Freeze Frame/Failure Records. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM.
  4. Turn OFF the engine. Disconnect the respective ignition coil electrical connector. Start the engine. Measure the frequency at the ignition control circuit using the Digital Multimeter (DMM) set to DC Hertz. Is the frequency 3-20 Hz? If yes, go to step  8. If no, go to next step.
  5. Measure the voltage at the ignition control circuit using the DMM. Is the voltage more than 1 V? If yes, go to step  14. If no, go to next step.
  6. Turn OFF the ignition. Disconnect the PCM connector. Test the continuity from the ignition control circuit at the ignition coil electrical connector to the PCM connector using the DMM. Does the DMM indicate continuity? If yes, go to next step. If no, go to step  15.
  7. Test the respective IC circuit for a short to ground. Did you find and correct the condition? If yes, go to step  18. If no, go to step  16.
  8. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the ignition coil with a test lamp connected to battery ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  10.
  9. Probe the ground circuit of the ignition coil with a test lamp connected to battery voltage. Does the test lamp illuminate? If yes, go to step  12. If no, go to step  11.
  10. Repair the open in the ignition 1 voltage circuit. After repairs, go to step  18.
  11. Repair the open in the ground circuit for the ignition coil. After repairs, go to step  18.
  12. Inspect for poor connections at the harness connector of the ignition coil. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  13. Replace the ignition coil. After repairs, go to step  18.
  14. Repair the IC circuit for a short to voltage. After repairs, go to step  18.
  15. Repair the IC circuit for an open circuit. After repairs, go to step  18.
  16. Inspect for poor connections at the harness connector of the PCM. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  17. Replace the PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  18. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  3.
  19. Observe the stored information, Capture Info with a scan tool. 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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