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Home >> Chevrolet >> 2000 >> Lumina >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Self-Diagnostics - 3.1L >> Diagnostic Tests >> DTC P0620: Generator Performance >> Diagnostic Procedure
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Diagnostic Procedure

  1. Perform powertrain diagnostic system check. See POWERTRAIN DIAGNOSTIC SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing powertrain diagnostic system check, go to next step.
  2. Turn ignition off. Disconnect generator harness connector. Measure voltage between ground and generator harness connector terminal "L" (Red wire). Start engine. While observing voltage, command generator on with scan tool. If voltage changes from zero volts to 5 volts, repair charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If voltage does not change from zero volts to 5 volts, go to next step.
  3. Check for open or short to ground in Red wire between generator harness connector and PCM harness connector C2 terminal No. 61. Repair circuit as necessary, then go to step  7. If circuit is okay, go to next step.
  4. Check for short to voltage in Red wire between generator harness connector and PCM harness connector C2 terminal No. 61. Repair circuit as necessary, then go to step  7. If circuit is okay, go to next step.
  5. Check for poor connection at PCM connector. If a problem is found, repair as necessary. After repairs, go to step  7. If connection is okay, go to next step.
  6. Replace PCM. Program replacement PCM using required equipment. See PROGRAMMING . After replacing PCM, go to next step.
  7. Using scan tool, read and record FAILURE RECORDS DATA, and clear DTCs. Operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, select SPECIFIC DTC INFO for this DTC. If scan tool displays that this DTC FAILED THIS IGN, return to step  2. If scan tool does not display that this DTC FAILED THIS IGN, system is okay.
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