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Home >> Chevrolet >> 2003 >> Venture Base, Van Passenger Extended >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0650: Mil Control Circuit >> Diagnostic Procedures
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Diagnostic Procedures

  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. Verify whether the instrument cluster is operational. If the instrument panel (I/P) is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in appropriate ACCESSORIES & EQUIPMENT article. Command the MIL ON and OFF with a scan tool. Does the MIL turn ON and OFF when commanded with a scan tool? If yes, go to next step. If no, go to step  4.
  3. Observe the Freeze Frame/Failure Records for this DTC. Turn ignition off for 30 seconds. Start engine. Operate the 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. Does the DTC fail this ignition? If yes, go to next step. If no, problem is intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 3.4L MONTANA, SILHOUETTE & VENTURE article.
  4. Inspect the fuse that supplies ignition voltage to the MIL. Is the fuse open? If yes, go to step  12. If no, go to next step.
  5. Turn ignition off. Disconnect PCM harness connector. Turn ignition on. Is the MIL OFF? If yes, go to next step. If no, go to step  13.
  6. Turn ignition off. Remove the fuse that supplies voltage to the MIL. Turn ignition on, with engine off. Measure the voltage from the MIL control circuit to a good ground. Is the voltage less than 0.3 volt? If yes, go to next step. If no, go to step  14.
  7. Turn ignition off. Install the fuse that supplies voltage to the MIL. Turn ignition on, with engine off. Connect a 3-amp fused jumper wire between the MIL control circuit of the PCM and a good ground. Is the MIL illuminated? If yes, go to step  11. If no, go to next step.
  8. Turn ignition off. Remove the Instrument Panel Cluster (IPC). Probe the MIL battery positive voltage circuit of the IPC harness connector with a test light that is connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  15.
  9. Test the MIL control circuit for an open or high resistance. Did you find and correct a condition? If yes, go to step  18. If no, go to next step.
  10. Test for an intermittent and for a poor connection at the IPC. Did you find and correct the condition? If yes, go to step  18. If no, go to step  16.
  11. 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.
  12. Repair short to ground in the battery positive voltage circuit. After repairs, go to step  18.
  13. Repair short to ground in the MIL control circuit. After repairs, go to step  18.
  14. Repair short to voltage in the MIL control circuit. After repairs, go to step  18.
  15. Repair open in the MIL ignition voltage circuit. After repairs, go to step  18.
  16. Replace IPC. After replacing IPC, go to step  18.
  17. Replace PCM. See REMOVAL & INSTALLATION - MONTANA, SILHOUETTE & VENTURE article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  18. Clear the DTCs with a scan tool. Turn ignition off for 30 seconds. Start engine. Operate the vehicle within the Conditions for Running DTC. See 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 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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