LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2003 >> Century Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L Engine >> Diagnostic Tests >> DTC P0201-P0206: Injector Control Circuit >> Diagnostic Procedure

Diagnostic Procedure

  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 Test. See CONDITIONS FOR RUNNING TEST . 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 next step. If no, go to DIAGNOSTIC AIDS .
  4. Turn ignition switch to OFF position. Disconnect the fuel injector harness multi-way connector. Probe the ignition 1 voltage circuit of the suspect fuel injector using a test light connected to a 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 an open and 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 fuel injector control circuit 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 conditions:
    • 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 appropriate article in ENGINES. 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. Test the fuel injector control circuit 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. Test the fuel injector ignition voltage circuit for an open between the fuel injector and splice. Did you find and correct the condition? If yes, go to step  18. If no, go to step  16.
  13. Test the fuel injector control circuit 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. Check for poor connections at the PCM harness connector. Did you find and correct the condition? If yes, go to step  18. If no, go to next step.
  15. Repair the short to ground in the fuel injector control circuit. After repair, go to step  18.
  16. Replace the appropriate fuel injector. 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 Test. See CONDITIONS FOR RUNNING TEST . 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.
scientia non olet · About LEMON Manuals