Alternator Control Circuit Troubleshooting
Alternator Control Circuit Troubleshooting
NOTE:Do this troubleshooting if, in step 5 of the alternator and regulator circuit troubleshooting Alternator and Regulator Circuit Troubleshooting, the battery voltage is less than 13.5 V.
1. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) Initial Inspection and Diagnostic Overview.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the vehicle and the engine control module (ECM)/powertrain control module (PCM). If it doesn't communicate, troubleshoot the DLC circuit Testing and Inspection.
4. Check for DTCs Initial Inspection and Diagnostic Overview. If a DTC is present, diagnose and repair the cause before continuing with this test.
5. Disconnect the alternator 4P connector from the alternator.
6. Start the engine, and turn on the headlights to high beam.
7. 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.
8. 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.
9. Disconnect ECM/PCM connector B (49P).
10. Check for continuity between ECM/PCM connector terminal B45 and body ground.
Is there continuity?
YES -
Repair a short in the wire between the alternator and the ECM/PCM.�
NO -
Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM Initial Inspection and Diagnostic Overview, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM Service and Repair.�
11. 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.
12. Disconnect ECM/PCM connector B (49P).
13. Check for continuity between ECM/PCM connector terminal B45 and alternator 4P connector terminal No. 2.
Is there continuity?
YES -
Replace the alternator Removal and Replacement, or repair the alternator Overhaul.�
NO -
Repair an open in the wire between the alternator and the ECM/PCM.�