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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 379 (Engine Controls Self-Diagnostics - 3.4L) >> Diagnostic Tests >> DTC P0201-P0206: Injector Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. 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. Clear the DTCs using a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters using a scan tool. Are any of the misfire current counters incrementing? If yes, go to step  4. If no, go to next step
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running as specified in the supporting text or as close to the Freeze Frame/Failure Records data that you observed. See CONDITIONS FOR RUNNING . Does the DTC fail this ignition? If yes, go to next step. If no, go to  10.
  4. Turn ignition switch to OFF position. Disconnect the fuel injector harness multi-way connector. Probe the appropriate fuel injector control circuit, Powertrain Control Module (PCM) side, using a test light connected to battery voltage. Crank the engine. Does the test light blink when cranking the engine? If yes, go to step  8. If no, go to next step.
  5. Does the test light remain illuminated at all times? If yes, go to step  7. If no, go to next step.
  6. Check the control circuit of the fuel injector for a short to voltage or an open between the multi-way connector and the PCM. Did you find and correct the condition? If yes, go to step  18. If no, go to step  14.
  7. Check the control circuit of the fuel injector for a short to ground between the multi-way connector and the PCM. Did you find and correct the condition? If yes, go to step  18. If no, go to step  17.
  8. Check the accessible fuel injector jumper harness between the multi-way connector and the plenum for the following:
    • Poor connections at the multi-way connector.
    • Damaged or pinched wiring.
    • Broken wires inside the insulation.

    Did you find and correct the condition? If yes, go to step  18. If no, go to next step.

  9. Remove the upper intake manifold. See UPPER INTAKE MANIFOLD in appropriate REMOVAL & INSTALLATION article. Probe the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector, using a test light connected to battery voltage. Does the test light illuminate? If yes, go to step  15. If no, go to next step.
  10. Using a DMM, test for continuity between the ignition voltage terminal and the appropriate fuel injector control circuit terminal, at the multi-way connector. Does the DMM indicate infinity? If yes, go to next step. If no, go to step  13.
  11. Check the control circuit of the fuel injector for an open, or poor connections at the fuel injector. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  12. Check the ignition voltage circuit of the fuel injector for an open between the fuel injector and the splice. Did you find and correct the condition? If yes, go to step  18. If no, go to step  16.
  13. Check the control circuit of the fuel injector for a short to voltage, or a short to another circuit. Did you find and correct the condition? If yes, go to step  18. If no, go to step  16.
  14. 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 step  17.
  15. Repair the short to ground in the fuel injector control circuit. After repair, go to step  18.
  16. Repair the short to ground in the fuel injector control circuit. After repair, go to step  18.
  17. Replace PCM. See POWERTRAIN CONTROL MODULE in appropriate REMOVAL & INSTALLATION article. Perform PCM relearn procedure. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After replacing PCM, go to next step.
  18. Using scan tool, clear the DTCs. Turn ignition switch to OFF position for 30 seconds. Start the engine. Operate the vehicle within the Conditions For Running. See CONDITIONS FOR RUNNING . Did the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  19. Using the scan tool, observe the stored information in 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 at this time.
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