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Home >> Oldsmobile >> 2000 >> Intrigue GLS >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0620: Generator Performance >> Diagnostic Procedures
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Diagnostic Procedures

  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD system check, go to next step.
  2. Start engine. Using scan tool, monitor generator Pulse Width Modulation (PWM). If scan tool indicates a PWM of 5-95 percent, go to next step. If scan tool does not indicate a PWM of 5-95 percent, go to step  4.
  3. Using scan tool, turn generator off. If scan tool indicates that generator PWM is zero percent, see DIAGNOSTIC AIDS . If scan tool does not indicate that generator PWM is zero percent, go to next step.
  4. Turn ignition off. Disconnect generator harness connector. Connect a DVOM between a known-good chassis ground and generator "L" terminal circuit at harness connector. Start engine. Using scan tool, command generator on and off. Voltage should read zero volts with generator off, then change to 5 volts with generator on. If voltage reading is as specified, go to next step. If voltage reading is not as specified, go to step  6.
  5. Turn ignition on, with engine off. Using a test light connected to battery voltage, probe generator "F" terminal circuit repeatedly, while monitoring generator PWM on scan tool. If generator PWM display is being affected, go to step  8. If generator PWM display is not being affected, go to step  7.
  6. Turn ignition off. Disconnect PCM harness connector. Check generator "L" terminal circuit for open, short to ground or short to voltage. Repair as necessary. After repairs, go to step  11. If circuit is okay, go to step  9.
  7. Turn ignition off. Disconnect PCM harness connector. Check generator "F" terminal circuit for open, short to ground or short to voltage. Repair as necessary. After repairs, go to step  11. If circuit is okay, go to step  9.
  8. Check for poor connection or terminal tension at generator connector. Repair as necessary. After repairs, go to step  11. If connection or terminal tension is okay, see DIAGNOSTIC AIDS .
  9. Check for poor connection or terminal tension at PCM connector. Repair as necessary. After repairs, go to step  11. If connection or terminal tension is okay, go to next step.
  10. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
  11. Using scan tool, review and record FAIL RECORDS data. Clear DTCs. Operate vehicle within FAIL RECORDS conditions as noted. Using scan tool, monitor SPECIFIC DTC INFO for this DTC. If scan tool indicates that this DTC failed this ignition, go to step  2. If scan tool does not indicate that this DTC failed this ignition, system is okay.
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