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Home >> Saturn >> 2000 >> LS Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0621: Generator "L" Terminal Circuit >> 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, command generator "L" terminal on and off, while observing "F" terminal status. If "F" terminal reads zero percent when "L" terminal is commanded off and greater than zero percent when "L" terminal is commanded on, problem is intermittent. If "F" terminal does not read zero percent when "L" terminal is commanded off and not greater than zero percent when "L" terminal is commanded on, go to next step.
  3. Turn ignition off. Disconnect generator 2-pin harness connector. Turn ignition on, with engine off. Using scan tool, command generator "L" terminal off. Using a DVOM, check voltage on generator harness connector terminal No. 1 (Red wire). If voltage reading is about zero volts, go to next step. If voltage reading is not about zero volts, check circuit for short to voltage. Repair as necessary. If circuit is okay, replace PCM.
  4. Command generator "L" terminal on. If voltage reading is about 5 volts, check for terminal tightness at connectors. Repair as necessary. If voltage reading is not about 5 volts, check Red wire circuit for short or open circuit. Repair as necessary. If circuit is okay, check for terminal tightness. Repair as necessary. If terminals are okay, replace PCM.
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