Control Circuit Troubleshooting
Alternator Control Circuit Troubleshooting1. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC), and check for DTCs. If a DTC is present, diagnose and repair the cause before continuing with this test.
2. Disconnect the alternator 4P connector from the alternator.
3. Start the engine, and turn on the headlights to high beam.
4. 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 5.
NO - Go to step 8.
5. Jump the SCS line with the HDS, then turn the ignition switch OFF.
NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
6. Disconnect PCM connector C (44P).
7. Check for continuity between PCM connector terminal C38 and body ground.
Is there continuity?
YES - Repair short in the wire between the alternator and PCM.
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM.
8. Jump the SCS line with the HDS, then turn the ignition switch OFF.
NOTE: This step must be done to protect the powertrain control module (PCM) from damage.
9. Disconnect PCM connector C (44P).
10. Check for continuity between PCM connector terminal C38 and alternator 4P connector terminal No. 2.
Is there continuity?
YES - Replace the alternator or repair the alternator.
NO - Repair an open in the wire between the alternator and PCM.