Honda Civic. Manual — part 15

DTC 81-11: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-

51: CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION; DTC 81-52:
CENTRAL PROCESSING UNIT (CPU) INTERNAL CIRCUIT MALFUNCTION

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0).
4. Test-drive the vehicle.
5. Check for DTCs with the HDS.

Is DTC 81-11, 81-51, or 81-52 indicated?

YES - Replace the ABS modulator-control unit: Except Si model (see
REMOVAL - EXCEPT SI MODEL ), Si model (see REMOVAL - SI
MODEL ).

NO - Intermittent failure, the system is OK at this time.

DTC 86-01: F-CAN BUS-OFF MALFUNCTION

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0), then turn it ON (II) again.
4. Check for DTCs with the HDS.

Is DTC 86-01 indicated?

YES - Go to step 5.

NO - Intermittent failure, the system is OK at this time. Check for loose
terminals between ECM/PCM connector A (44P) and the ABS modulator-
control unit 25P connector. Refer to INTERMITTENT FAILURES
TROUBLESHOOTING .

5. Turn the ignition switch to LOCK (0).
6. Short the SCS line with the HDS.
7. Disconnect ECM/PCM connector A (44P).

2008 Honda Civic GX

2006-08 BRAKES ABS System - Civic (All Except Hybrid)

8. Disconnect the HDS from the data link connector (DLC).
9. Disconnect the gauge control module (tach) 36P connector.

10. Disconnect SRS unit connector A (28P).
11. With EPS: Disconnect EPS control unit connector D (28P).
12. With TPMS: Disconnect the TPMS control unit 20P connector.
13. Disconnect the ABS modulator-control unit 25P connector.
14. Check for continuity between the ABS modulator-control unit 25P connector

terminals No. 1 and No. 17 and body ground individually.

Fig. 27: Checking Continuity Between ABS Modulator-Control Unit 25P
Connector Terminals No. 1 And No. 17 And Body Ground

Is there continuity?

YES - Repair short to body ground in the wire between the ECM/PCM, the
gauge control module (tach), the data link connector (DLC), the SRS unit, the
EPS control unit (if equipped), the TPMS control unit (if equipped), and the
ABS modulator-control unit.

NO - Go to step 15.

15. Check for continuity between body ground and the ABS modulator-control

unit 25P connector terminals No. 1 and No. 17 individually.

2008 Honda Civic GX

2006-08 BRAKES ABS System - Civic (All Except Hybrid)

Fig. 28: Checking Continuity Between ABS Modulator-Control Unit 25P
Connector Terminals No. 1 And No. 17

Is there continuity?

YES - Repair short in the wires between ABS modulator-control unit 25P
connector terminals No. 1 (CAN-H line) and No. 17 (CAN-L line).

NO - Go to step 16.

16. Check for continuity between ABS modulator-control unit 25P connector

terminal and ECM/PCM connector A (44P) terminal (see ABS
MODULATOR-CONTROL UNIT 25P CONNECTOR TERMINAL AND
ECM/PCM CONNECTOR A (44P) TERMINAL ).

ABS MODULATOR-CONTROL UNIT 25P CONNECTOR TERMINAL
AND ECM/PCM CONNECTOR A (44P) TERMINAL

Sign

Connector Terminal No.

ABS Modulator-control Unit ECM/PCM

CAN-L

17

37

CAN-H

1

36

2008 Honda Civic GX

2006-08 BRAKES ABS System - Civic (All Except Hybrid)

Fig. 29: Checking Continuity Between ABS Modulator-Control Unit 25P
Connector Terminal And ECM/PCM Connector A (44P) Terminal

Is there continuity?

YES - Check for loose terminals in the ABS modulator-control unit 25P
connector. If necessary, substitute a known-good ABS modulator-control unit:
Except Si model (see REMOVAL - EXCEPT SI MODEL ), Si model (see
REMOVAL - SI MODEL ), and retest.

NO - Repair open in the wire between the ECM/PCM and the ABS modulator-
control unit.

DTC 86-24: F-CAN COMMUNICATION WITH ENGINE MALFUNCTION; DTC 86-25: F-CAN
COMMUNICATION WITH ENGINE MALFUNCTION

1. Turn the ignition switch ON (II).
2. Clear the DTC with the HDS.
3. Turn the ignition switch to LOCK (0).
4. Test-drive the vehicle. Drive the vehicle at 7 mph (10 km/h) or more.
5. Check for DTCs with the HDS.

Is 86-24, and/or 86-25 DTC indicated?

2008 Honda Civic GX

2006-08 BRAKES ABS System - Civic (All Except Hybrid)