Alternator Control Circuit Troubleshooting
  1. Check for continuity between ECM/PCM connector terminal B45 and body ground.
Is there continuity?
YES -
Repair short in the wire between the alternator and the ECM/PCM.■
NO -
Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. ■
  1. Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).
    NOTE: This step must be done to protect the ECM/PCM from damage.
  1. Disconnect ECM/PCM connector B (49P).