Alternator Control Circuit Troubleshooting
  1. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC).
  1. Turn the ignition switch to ON (II).
  1. Make sure the HDS communicates with the vehicle and the engine control module (ECM)/powertrain control module (PCM). If it doesn't, troubleshoot the DLC circuit.
  1. Check for DTCs. If a DTC is present, diagnose and repair the cause before continuing with this test.
  1. Disconnect the alternator 4P connector from the alternator.
  1. Start the engine, and turn on the headlights to high beam.
  1. Measure the voltage between alternator 4P connector terminal No. 2 and the positive terminal of the battery.
Is there 1 V or less?
YES -
Go to Step 11 .
NO -
Go to Step 8 .
  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 (44P).