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Home >> Saturn >> 2003 >> LW200 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P1640: Control Module Output 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, go to DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Is DTC P0560, P0563, P0753, P0758 or P1860 set? If yes, diagnose affected DTC(s). See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, go to next step.
  3. Observe the General Info - Output Data List with a scan tool. Do any parameters indicate a fault present? If yes, go to next step. If no, go to step  5.
  4. Test for a short to voltage on the control circuit of the component that indicated a fault. Did you find and correct the condition? If yes, go to step  6. If no, go to next step.
  5. Replace PCM. See POWERTRAIN CONTROL MODULE in REMOVAL & INSTALLATION - SATURN "L" SERIES article. Perform PCM relearn procedure. See PCM REPROGRAMMING  under PROGRAMMING. After replacing PCM, go to next step.
  6. 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 the DTC. See CONDITIONS FOR RUNNING DTC . Vehicle could also be operated within the conditions that you observed from the Freeze Frame/Failure Records. Does the DTC fail this ignition? If yes, go to step  2. If no, go to next step.
  7. Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? If yes, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no, system is okay.
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