21-01

EPS DTC Troubleshooting: 21-01, 21-02

DTC 21-01:

Excessive Change of the Vehicle Speed Signal

DTC 21-02:

Comparison between the Vehicle Speed and the Engine Speed Signal

NOTE:

- If the MIL indicator is on, troubleshoot the fuel and emissions systems first.
- Even though the system is operating normally, the EPS indicator will come on caused by the detecting condition of DTC 21-01 or DTC 21-02 when you raise the engine speed with the vehicle stopped.
- Clear the DTC related to the ABS or VSA system.

1. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

2. Raise and support the vehicle Service and Repair, and allow all wheels to rotate freely.

3. Connect the HDS to the data link connector (DLC).

4. Turn off the VSA function by using the VSA OFF switch.

5. Start the engine, then run the vehicle in the 4th (M/T), or D position (A/T).

6. Check the VEHICLE SPEED in the EPS DATA LIST with the HDS.

Is the vehicle speed indicated?

YES -

The system is OK at this time.

NO -

Go to step 7.

7. Check for DTCs in the fuel and emissions systems (M/T) or A/T system (A/T) with the HDS.

Is DTC P0720 (M/T), P0721 (A/T), P0722 (A/T), or P0723 (A/T) indicated?

YES -

Troubleshoot the indicated DTC(s).

NO -

Go to step 8.

8. Start the engine, and check the tachometer.

Is the tachometer working correctly?

YES -

Go to step 10.

NO -

Go to step 9.

9. Check for DTCs in the gauge control module with the HDS.

Are any DTCs indicated?

YES -

Troubleshooting the indicated DTC(s).

NO -

Update the ECM/PCM if it does not have the latest software ECM/PCM Update, or substitute a known-good ECM/PCM, then go to step 1 and recheck. If the ECM/PCM was updated and DTCs are not indicated, troubleshooting is complete. If the ECM/PCM was substituted and DTCs are not indicated, replace the original ECM/PCM Service and Repair.

10. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

11. Short the SCS line with the HDS.

12. Disconnect EPS control unit connector D (28P) and ECM/PCM connector A (49P).

13. Check for continuity between EPS control unit connector D (28P) terminal No. 1 and ECM/PCM connector A (49P) terminal No. 48.





Is there continuity?

YES -

Go to step 14.

NO -

Repair an open in the wire between the EPS control unit and the ECM/PCM.

14. Check for continuity between EPS control unit connector D (28P) terminal No. 15 and ECM/PCM connector A (49P) terminal No. 49.





Is there continuity?

YES -

Replace the EPS control unit Service and Repair.

NO -

Repair an open in the wire between the EPS control unit and the ECM/PCM.