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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 370 (Engine Control System - Self-Diagnostics - 4.2L) >> Diagnostic Tests >> DTC P0201-P0206: Fuel Injector Control Circuit >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. 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, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Observe the Freeze Frame/Failure Records data for this DTC. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions For Running DTC or as close to the Freeze Frame/Failure Records data that you observed. Does the DTC fail this ignition cycle? If yes, go to next step. If no, see DIAGNOSTIC AIDS .
  3. Turn ignition off. Disconnect the fuel injector harness multi-way connector. Probe the appropriate fuel injector control circuit, PCM side, with a test light connected to battery voltage. Crank the engine. Does the test light flash when cranking the engine? If yes, go to step  7. If no, go to next step.
  4. Does the test light remain illuminated at all times? If yes, go to step  6. If no, go to next step.
  5. Test 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  13.
  6. Test 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.
  7. Inspect the accessible fuel injector jumper harness between the multi-way connector and the intake manifold 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.

  8. Probe the appropriate fuel injector control circuit, fuel injector side, at the multi-way connector, with a test light connected to battery voltage. Does the test light illuminate? If yes, go to step  15. If no, go to next step.
  9. With a DVOM, test for continuity between the ignition 1 voltage supply terminal and the appropriate fuel injector control circuit terminal, at the multi-way connector. Does the DVOM indicate OL? If yes, go to next step. If no, go to step  12.
  10. Test the control circuit of the fuel injector for an open or for 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.
  11. Test the ignition 1 voltage supply 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.
  12. Test 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.
  13. 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.
  14. Test for an intermittent and for a poor connection at the PCM. Did you find and correct the condition? If yes, go to step  18. If no, go to step  17.
  15. Repair short to ground in the fuel injector control circuit. After repairs, go to step  18.
  16. Replace appropriate fuel injector. See REMOVAL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article. After repairs, go to step  18.
  17. Replace PCM. See REMOVAL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  18. Clear the DTCs with scan tool. Turn ignition off for 30 seconds. Start engine. Operate vehicle within the Conditions For Running DTC. Does the DTC run and pass? If yes, go to next step. If no, go to step  2.
  19. Observe the stored information, Capture Info with scan tool. Does 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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