Honda Civic. Manual — part 365

CIRCUIT DIAGRAM

REGULATOR CIRCUIT
TROUBLESHOOTING ).

5. Check for a poor connection at the battery

terminal.

6. Test the battery (see BATTERY TEST ).

Battery
overcharged

1. Troubleshoot the alternator and regulator

circuit (see ALTERNATOR AND
REGULATOR CIRCUIT
TROUBLESHOOTING ).

2. Test the battery (see BATTERY TEST ).

2008 Honda Civic GX

2006-08 ELECTRICAL Charging System (R18A1) - Civic (All Except Hybrid)

Fig. 2: Charging System - Circuit Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

CHARGING SYSTEM INDICATOR CIRCUIT TROUBLESHOOTING

1. Turn the ignition switch ON (II).

Does the charging system indicator come on?

2008 Honda Civic GX

2006-08 ELECTRICAL Charging System (R18A1) - Civic (All Except Hybrid)

YES -Go to step 2.

NO -Go to step 14.

2. Start the engine. Hold the engine speed at 2,000 rpm for 1 minute.

Does the charging system indicator go off?

YES -Charging system indicator circuit is OK. Go to the ALTERNATOR
AND REGULATOR CIRCUIT TROUBLESHOOTING .

NO -Go to step 3.

3. Do the gauge control module self-diagnostic function procedure (see SELF-

DIAGNOSTIC FUNCTION ).

Does the charging system indicator flash?

YES -Go to step 4.

NO -Replace the gauge control module (tach) (see REPLACEMENT ).

4. Turn the ignition switch to LOCK (0)
5. Disconnect the alternator 4P connector.
6. Turn the ignition switch ON (II).

Does the charging system indicator go off?

YES -Replace the alternator (see ALTERNATOR REMOVAL AND
INSTALLATION ), or repair the alternator (see ALTERNATOR
OVERHAUL ).

NO -Go to step 7.

7. Turn the ignition switch to LOCK (0).

NOTE:

The charging system indicator may come on and then
go off.

2008 Honda Civic GX

2006-08 ELECTRICAL Charging System (R18A1) - Civic (All Except Hybrid)

8. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC)

(see step 2 on HOW TO USE THE HDS (HONDA DIAGNOSTIC
SYSTEM) ).

9. Turn the ignition switch ON (II).

10. Make sure the HDS communicates with the vehicle and the engine control

module (ECM)/powertrain control module (PCM). If it doesn't, troubleshoot
the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).

11. Jump the SCS line with the HDS, then turn the ignition to LOCK (0).

12. Disconnect ECM/PCM connector B (44P).
13. Check for continuity between ECM/PCM connector terminal B42 and body

ground.

Fig. 3: Checking For Continuity Between ECM/PCM Connector Terminal
B42 And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Repair short in the wire between the alternator and the ECM/PCM.

NO -Update the ECM/PCM if it does not have the latest software (see
UPDATING ECM/PCM ), or substitute a known-good ECM/PCM (see
SUBSTITUTING THE ECM/PCM ), then recheck. If the

NOTE:

This step must be done to protect the ECM/PCM from
damage.

2008 Honda Civic GX

2006-08 ELECTRICAL Charging System (R18A1) - Civic (All Except Hybrid)