Alternator Control Circuit Troubleshooting
NOTE:
Do this troubleshooting if, in step 4 of the alternator and regulator circuit troubleshooting (see ALTERNATOR AND REGULATOR CIRCUIT TROUBLESHOOTING
), the battery voltage is less than 13.5 V.
- Connect the HDS to the DLC (see step 2 under GENERAL TROUBLESHOOTING INFORMATION ).
- Turn the ignition switch to ON (II).
- Make sure the HDS communicates with the vehicle and the PCM. If it does not communicate, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
- Check for DTCs (see GENERAL TROUBLESHOOTING INFORMATION ). If a DTC is present, diagnose and repair the cause before continuing with this test.
- Disconnect the alternator 4P connector.
- Start the engine, and turn on the headlights to high beam.
- Measure the voltage between alternator 4P connector terminal No. 2 and the positive terminal of the battery.Fig 1: Measuring Voltage Between Alternator 4P Connector Terminal No. 2 And Positive Terminal Of Battery
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there less than 1 V?
YES -Go to step 11.
NO -Go to step 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 PCM from damage.
- Disconnect PCM connector C (49P).
- Check for continuity between PCM connector terminal C43 and body ground.
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Repair a short to ground in the wire between alternator 4P connector terminal No. 2 and PCM connector terminal C43.
NO -Update the PCM if it does not have the latest software (see KNOCK SENSOR REPLACEMENT ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the symptom/indication goes away with a known-good PCM, replace the original PCM (see PCM REPLACEMENT J.
- Jump the SCS line with the HDS, then turn the ignition switch to LOCK (0).NOTE: This step must be done to protect the PCM from damage.
- Disconnect PCM connector C (49P).
- Check for loose terminals and connections, then check for continuity between PCM connector terminal C43 and alternator 4P connector terminal No. 2.Fig 3: Checking Continuity Between PCM Connector Terminal C43 And Alternator 4P Connector Terminal No. 2
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Is there continuity?
YES -Replace the alternator (see ALTERNATOR REMOVAL AND INSTALLATION ), or repair the alternator (see ALTERNATOR OVERHAUL ).
NO -Repair an open in the wire between the alternator 4P connector terminal No. 2 and PCM connector terminal C43.