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Home >> Chevrolet >> 2001 >> Camaro Base, 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (Engine Control System Self-Diagnostics - 5.7L) >> Diagnostic Tests >> DTC P1638: Generator "F" Terminal Circuit ("Y" Body) >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2000 Pontiac Firebird, 2000 Chevrolet Corvette, and 2000 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK . After performing OBD system check, go to next step.
  2. Ensure battery is fully charged. Turn ignition on, with engine off. Using scan tool, monitor DTC information. If DTC P1637 and/or P1638 failed in this ignition cycle, go to step  4. If DTC P1637 and/or P1638 did not fail in this ignition cycle, go to next step.
  3. Start and operate engine at idle. Using scan tool, monitor DTC information. If DTC P1637 and/or P1638 failed in this ignition cycle, go to next step. If DTC P1637 and/or P1638 did not fail in this ignition cycle, see DIAGNOSTIC AIDS .
  4. Turn ignition off. Disconnect generator 4-pin harness connector. Turn ignition on, with engine off. Using test light connected to ground, probe generator sensor circuit (terminal "S") and generator battery feed circuit (mounted on rear of generator). If test light illuminates on both circuits, go to next step. If test light does not illuminate on both circuits, diagnose charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
  5. Turn ignition off. Reconnect 4-pin harness connector. Turn on, with engine off. Using scan tool in ENGINE 3 DATA LIST, monitor "L" terminal parameter. If scan tool indicates that "L" terminal as inactive, go to next step. If scan tool does not indicate that "L" terminal as inactive, go to step  8.
  6. Using scan tool in ENGINE 3 DATA LIST, monitor "F" terminal parameter. If scan tool indicates that "F" terminal is less than 40 percent, go to next step. If scan tool indicates that "F" terminal is not less than 40 percent, go to step  13.
  7. Start and operate engine at idle. Using scan tool, monitor "L" terminal parameter. If scan tool indicates that "L" terminal as inactive, go to step  14. If scan tool does not indicate that "L" terminal as inactive, go to step  10.
  8. Turn ignition off. Disconnect generator 4-pin harness connector. Jumper "L" terminal at harness connector to ground. Using scan tool, monitor "L" terminal. If scan tool indicates that "L" terminal as inactive, go to step  20. If scan tool does not indicate that "L" terminal as inactive, go to next step.
  9. Turn ignition off. Disconnect PCM harness connector. Check resistance of "L" terminal circuit from PCM harness connector to generator harness connector. If resistance is 0-2 ohms, go to step  18. If resistance is not 0-2 ohms, go to step  15.
  10. Disconnect generator 4-pin harness connector. Using a test light connected to battery voltage, probe test light to generator "F" terminal at generator harness connector. Using scan tool, monitor "F" terminal. If generator "F" terminal parameter changes from 0-99 percent, go to step  20. If generator "F" terminal parameter does not change from 0-99 percent, go to next step.
  11. Check resistance between battery ground and "F" terminal circuit at generator harness connector. If resistance is 0-10 ohms, go to step  16. If resistance is not 0-10 ohms, go to next step.
  12. Turn ignition off. Disconnect PCM harness connector. Check resistance of "F" terminal circuit between PCM harness connector and generator harness connector. If resistance is 0-2 ohms, go to step  18. If resistance is not 0-2 ohms, go to step  15.
  13. Disconnect generator 4-pin harness connector. Using scan tool, monitor "F" terminal parameter. If parameter is zero percent, go to step  21. If parameter is not zero percent, go to step  17.
  14. Disconnect generator 4-pin harness connector. Using scan tool, monitor "L" terminal parameter. If scan tool indicates that "L" terminal parameter is inactive, go to step  16. If scan tool does not indicate that "L" terminal parameter is inactive, go to step  21.
  15. Repair open/high resistance is generator circuit. After repairs, go to step  22.
  16. Repair short to ground in generator circuit. After repairs, go to step  22.
  17. Repair short to voltage in "F" terminal circuit. After repairs, go to step  22.
  18. Check for poor connection at PCM harness connector. Repair as necessary. After repairs, go to step  22. If connections are okay, go to next step.
  19. Replace PCM. Program replacement PCM using required equipment.
  20. Check for poor connection at generator harness connector. Repair as necessary. After repairs, go to step  22. If connection is okay, go to next step.
  21. Replace generator. After replacing generator, go to next step.
  22. 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 indicates that this DTC FAILED THIS IGN, return to step  2. If scan tool does not indicate that this DTC FAILED THIS IGN, go to next step.
  23. Using scan tool, select CAPTURE INFO and REVIEW INFO option. If any undiagnosed DTCs are set, diagnose affected DTCs.
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