P063A-GENERATOR VOLTAGE SENSE CIRCUIT





For a complete wiring diagram Refer to Section 8W.


  • When Monitored:

    The engine running. The engine speed greater than 1157 RPM.

  • Set Condition:

    The PCM recognizes the alternator output voltage is less than the Battery feed circuit voltage. One trip failure. The Generator light will illuminate. The fault will be checked again on the next key cycle.


Possible Causes
  
EXCESSIVE RESISTANCE IN THE (A803) GENERATOR SENSE CIRCUIT
  
(A803) GENERATOR SENSE CIRCUIT SHORTED TO GROUND
  
GENERATOR
  
PCM
  

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).



Diagnostic Test

1.ACTIVE DTC

NOTE: Inspect the vehicle for aftermarket accessories that may exceed the Generator System output.

NOTE: The battery must be fully charged.

NOTE: The Generator belt tension and condition must be checked before continuing.








Is the DTC Active at this time?

Yes
  • Go To 2


No

2.EXCESSIVE RESISTANCE IN THE (A803) GENERATOR SENSE CIRCUIT






CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.




Is the resistance below 5.0 ohms?

Yes
  • Go To 3


No

3.(A803) GENERATOR SENSE CIRCUIT SHORTED TO GROUND





Is the resistance below 100 ohms?

Yes


No
  • Go To 4

4.GENERATOR OPERATION







NOTE: The DTC needs to be cleared before actuating the Solenoid, if the DTC is not cleared, the Solenoid may not be allowed to actuate.



Does the test light illuminate brightly and flash on and off?

Yes


No
  • Go To 5

5.PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.




Were there any problems found?

Yes


No