Honda Civic. Manual — part 509

2. Raise the vehicle, and support it with safety stands in the proper locations (see

LIFT AND SUPPORT POINTS ), and allow all wheels to rotate freely.

3. Connect the HDS to the data link connector (DLC).
4. Start the engine, run the vehicle in 4th gear.
5. Check the VEHICLE SPEED in the DATA LIST with the HDS.

Is the vehicle speed indicated?

YES -The system is OK at this time.

NO -Go to step 6.

6. Check for DTCs in the fuel and emissions systems with the HDS.

Is DTC P0720 indicated?

YES -Troubleshoot the indicated DTC.

NO -Go to step 7.

7. Start the engine and check the tachometer.

Is the tachometer working correctly?

YES -Go to step 8.

NO -Troubleshoot the gauge control module (tach) (see SELF-DIAGNOSTIC
FUNCTION ).

8. Turn the ignition switch to LOCK (0).
9. Short the SCS line with the HDS.

10. Disconnect ECM connector A (44P) and EPS control unit connector D (28P).
11. Check for continuity between EPS control unit connector D (28P) terminals

No. 1 and ECM connector A (44P) terminals No. 36.

2008 Honda Civic EX

2006-08 STEERING EPS System - Civic (All Except Hybrid & Si)

Fig. 15: Checking Continuity Between EPS Control Unit Connector D
(28P) Terminals No. 1 And ECM Connector A (44P) Terminals No. 36

Is there continuity?

YES -Go to step 12.

NO -Repair open in the wire between the EPS control unit and the ECM.

12. Check for continuity between EPS control unit connector D (28P) terminals

No. 15 and ECM connector A (44P) terminals No. 37.

Fig. 16: Checking Continuity Between EPS Control Unit Connector D
(28P) Terminals No. 15 And ECM Connector A (44P) Terminals No. 37

2008 Honda Civic EX

2006-08 STEERING EPS System - Civic (All Except Hybrid & Si)

Is there continuity?

YES -Check for loose terminals in the EPS control unit connectors, and repair
if necessary. If no poor connections are found, replace the EPS control unit
(see EPS CONTROL UNIT REMOVAL/INSTALLATION ).

NO -Repair open in the wire between the EPS control unit and the ECM.

DTC 22-01: ENGINE SPEED SIGNAL (INITIAL DIAGNOSIS)

1. Turn the ignition switch to LOCK (0).
2. Connect the HDS to the data link connector (DLC).
3. Start the engine.
4. Check the ENGINE SPEED in the DATA LIST with the HDS.

Is there 0 rpm at idle?

YES -Go to step 5.

NO -The system is OK at this time.

5. Turn the ignition switch to LOCK (0).
6. Disconnect EPS control unit connector D (28P).
7. Start the engine.
8. Measure voltage between EPS control unit connector D (28P) terminal No. 3

and body ground.

NOTE:

If the MIL indicator is on, troubleshoot the fuel and
emissions systems first.

2008 Honda Civic EX

2006-08 STEERING EPS System - Civic (All Except Hybrid & Si)

Fig. 17: Measuring Voltage Between EPS Control Unit Connector D (28P)
Terminal No. 3 And Body Ground

Is there any voltage?

YES -Check for loose terminals in the EPS control unit connectors, and repair
if necessary. If no poor connections are found, replace the EPS control unit
(see EPS CONTROL UNIT REMOVAL/INSTALLATION ).

NO -Go to step 9.

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

10. Check for continuity between EPS control unit connector D (28P) terminal No.

3 and body ground.

Fig. 18: Checking Continuity Between EPS Control Unit Connector D
(28P) Terminal No. 3 And Body Ground

Is there continuity?

YES -Repair short to body ground in the wire between the EPS control unit

2008 Honda Civic EX

2006-08 STEERING EPS System - Civic (All Except Hybrid & Si)