Alternator FR Signal Circuit Troubleshooting

1. Start the engine, and let it idle.

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

1. Check if the indicated percentage is varied when the lighting switch is turned ON.

Is the percentage varied?

YES | - | The alternator signal circuit is OK.■
NO | - | Go to Step 4 .

1. Turn the lighting witch and ignition switch OFF.

1. Disconnect the alternator 4P connector.

1. Turn the ignition switch ON (II).

1. Measure voltage between ECM/PCM connector terminals A9 and B13.

Is there about 5 V?

YES | - | Go to Step 8 .
NO | - | Go to Step 14 .

1. Turn the ignition switch OFF.

1. Jump the SCS line with the HDS.

1. Disconnect ECM/PCM connector B (24P).

1. Disconnect the alternator 4P connector.

1. Connect alternator 4P connector terminal No. 4 to body ground with a jumper wire.

1. Check for continuity between body ground and ECM/PCM connector terminal B13.

Is there continuity?

YES | - | Test the alternator. ■
NO | - | Repair open in the wire between the ECM/PCM (B13) and the alternator.■

1. Turn the ignition switch OFF.

1. Jump the SCS line with the HDS.

1. Disconnect ECM/PCM connector B (24P).

1. Check for continuity between body ground and ECM/PCM connector terminal B13.

Is there continuity?

YES | - | Repair short in the wire between the ECM/PCM (B13) and the alternator.■
NO | - | Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM / PCM .■