Charging System: Testing and Inspection
Charging Circuit TroubleshootingIf the charging system indicator does not come on or does not go off, or the battery is dead or low, test the following items in the order listed:
- Battery
- Charging system indicator test
- Alternator and regulator circuit test
- Alternator control system test
Charging System Indicator Test
1. Turn the ignition switch ON (II).
Does the charging system indicator come on?
YES - Go to step 2.
NO - Go to step 6.
2. Start the engine.
Does the charging system indicator go off?
YES - Charging system indicator circuit is OK. Go to the Alternator and Regulator Circuit Test.
NO - Go to step 3.
3. Turn the ignition switch OFF.
4. Disconnect the alternator 4P connector.
5. Turn the ignition switch ON (II).
Does the charging system indicator come on?
YES - Turn the ignition switch OFF, and repair a short in the wire between alternator and gauge assembly.
NO - Go to step 9.
6. Turn the ignition switch OFF.
7. Disconnect the alternator 4P connector.
8. Connect alternator 4P connector terminal No.3 to body ground with a jumper wire. Turn the ignition switch ON (II).
Does the charging system indicator come on?
YES - Go to step 9.
NO - Turn the ignition switch OFF. Check for a blown No.9 (10A) fuse in the driver's under-dash fuse/relay box and a blown charging system light bulb. If the fuse and bulb are OK, repair an open in the wire between the alternator and gauge assembly and/or the gauge assembly and driver's under-dash fuse/relay box.
9. Measure the voltage between alternator 4P connector terminal No.1 and body ground. Turn the ignition switch ON (II).
Is there battery voltage?
YES - Go to Alternator and Regulator Circuit Test.
NO - Check for a blown No.6 (15A) fuse in the driver's under-dash fuse/relay box and No.92 (7.5A) fuse in the auxiliary fuse holder 3. If the fuses are OK, repair an open in the wire between the alternator and auxiliary fuse holder 3, or auxiliary fuse holder 3 and driver's under-dash fuse/relay box.
Alternator and Regulator Circuit Test
1. Be sure the battery connections are good, and that the battery is sufficiently charged and in good condition.
2. Connect a VAT-40 (or equivalent tester), and turn the selector switch to position 1 (starting).
3. Shift to Park or Neutral, and start the engine. Hold the engine at 3,000 rpm, with no load until the radiator fan comes on, then let it idle.
4. Raise the engine speed to 2,000 rpm, and hold it there.
Is the voltage over 15.1 V?
YES - Replace the alternator or rear housing assembly.
NO - Go to step 5.
5. Release the accelerator pedal, and let the engine idle.
6. Make sure all accessories are turned off. Turn the selector switch to position 2 (charging).
7. Remove the inductive pick-up, and zero the ammeter.
8. Place the inductive pick-up over the B terminal wire of the alternator so that the arrow points away from the alternator.
9. Raise the engine speed to 2,000 rpm, and hold it there.
Is the voltage less than 13.5 V?
YES - Go to Alternator Control System Test.
NO - Go to step 10.
10. Apply a load with the VAT-40 until the battery voltage drops to between 12-13.5 V.
Is the amperage 87.5 A or more?
YES - The charging system is OK.
NO - Repair or replace the alternator.
Alternator Control System Test
1. 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 the headlights (high beam) ON.
4. Measure 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 the headlight switch OFF.
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. Using the HDS, go to the SCS mode and then follow the screens to ground the 16-pin DLC.
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 PCM.
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 the headlight switch OFF.
12. With the ignition switch ON (II), connect the Honda PGM Tester or 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 tester off and then back on. Go to the SCS mode and follow the screens to ground the 16-pin DLC.
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 - Repair or replace the alternator.
NO - Repair an open in the wire between the alternator and PCM.
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 is varied when the lighting switch is ON.
Is the percentage varied?
YES - The alternator signal circuit is OK.
NO - Go to step 4.
4. Turn the lighting switch and ignition switch OFF.
5. Disconnect the alternator 4P connector.
6. Turn the ignition switch ON (II).
7. Measure voltage between alternator 4P connector terminal No.4 and body ground.
Is there about 5 V?
YES - Replace the alternator, then go to step 1.
NO - Go to step 8.
8. Turn the ignition switch OFF.
9. Jump the SCS line with the HDS.
10. Disconnect PCM connector A (73P).
11. Check for continuity between alternator 4P connector No.4 terminal and body ground.
Is there continuity?
YES - Repair short in the wire between at the alternator connector and the PCM.
NO - Go to step 12.
12. Check for continuity between alternator 4P connector terminal No.4 and PCM connector A25.
Is there continuity?
YES - 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.
NO - Repair open in the wire between the alternator connector and the PCM.