Alternator FR Signal Circuit Troubleshooting

Alternator FR Signal Circuit Troubleshooting

1. Start the engine, and let it idle.

2. Monitor the ALTERNATOR in the DATA LIST with the HDS.

3. Check if the indicated percentage varies when the headlight switch is turned on.

Does the percentage vary?

YES -

The alternator signal circuit is OK.

NO -

Go to step 4.

4. Turn the headlight switch off and the ignition switch to LOCK (0).

5. Jump the SCS line with the HDS.

6. Disconnect the alternator 4P connector.

7. Disconnect ECM/PCM connector B (49P).

8. Check for continuity between ECM/PCM connector terminal B47 and body ground.





Is there continuity?

YES -

Repair a short in the wire between the ECM/PCM(B47) and the alternator.

NO -

Update the ECM/PCM if it does not have the latest software ECM/PCM Update (M/T), or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away and the ECM/PCM was updated, troubleshooting is complete. If the symptom/indication goes away, and the ECM/PCM was substituted, replace the original ECM/PCM Service and Repair.