Alternator Control Circuit Troubleshooting

Alternator Control Circuit Troubleshooting

NOTE: Do this troubleshooting if, 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). Reading and Clearing Diagnostic Trouble Codes

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 does not communicate, troubleshoot the DLC circuit. Testing and Inspection

4. Check for DTCs. Reading and Clearing Diagnostic Trouble Codes If a DTC is present, diagnose and repair the cause before continuing with this test.

5. Disconnect the alternator 4P connector.

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 less than 1 V?
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 (44P).

10. Check for continuity between ECM/PCM connector terminal B41 and body ground.

Is there continuity?
YES - Repair short to ground in the wire between alternator 4P connector terminal No. 2 and ECM/PCM connector terminal B41.

NO - Update the ECM/PCM if it does not have the latest software, ECM/PCM Update or substitute a known-good ECM/PCM, Reading and Clearing Diagnostic Trouble Codes 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 (44P).

13. Check for loose terminals and connectors, then check for continuity between ECM/PCM connector terminal B41 and alternator 4P connector terminal No. 2.

Is there continuity?
YES - Replace the alternator, Service and Repair or repair the alternator.

NO - Repair open in the wire between alternator 4P connector terminal No. 2 and ECM/PCM connector terminal B41.