Control Circuit Troubleshooting
Alternator Control Circuit Troubleshooting1. Check for proper operation of the electrical load detector (ELD) by checking the malfunction indicator lamp (MIL). If a DTC is present, diagnose and repair the cause before continuing with this test.
2. Disconnect the alternator 4P connector.
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 10.
NO - Go to step 5.
5. Turn off the headlights.
6. With the ignition switch ON (II), connect the Honda Diagnostic System (HDS) to the data link connector (DLC), and go into any of the live data screens.
NOTE: Steps 6 through 8 must be done to protect the powertrain control module (PCM) from damage.
7. Turn the ignition switch OFF.
8. Select "SCS" mode using the HDS.
9. Disconnect PCM connector A (73P).
10. Check for continuity between PCM connector A terminal No. 23 and body ground.
Is there continuity?
YES - Repair a short to ground in the wire between the alternator and the PCM.B
NO - Update the PCM if it does not have the latest software, or substitute a known-good PCM, then recheck. If the prescribed voltage is now available, and the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM.
11. Turn off the headlights,
12. With the ignition switch ON (II), connect the HDS to the DLC, and go into any of the live screens.
NOTE: Steps 12 through 14 must be done to protect the PCM from damage.
13. Turn the ignition switch OFF.
14. Turn the HDS off and then back on. Select "SCS" mode using the HDS.
15. Disconnect PCM connector A (73P).
16. Check for continuity between PCM connector A terminal No. 23 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 the PCM.