Alternator Control Circuit Troubleshooting
  1. Check for continuity between ECM connector No. 1 terminal No. 80 and body ground.
Is there continuity?
YES -
Repair short in the wire between the alternator and ECM.■
NO -
Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM. ■
  1. Jump the SCS line with the HDS, then turn the ignition switch OFF.
    NOTE: This step must be done to protect the ECM for damage.
  1. Disconnect ECM connector No. 1 (96P).