DTC Troubleshooting: 21-01, 21-02

DTC 21-01:  Vehicle Speed Signal (Regular diagnosis)
  
  

NOTE:
  • If the MIL indicator is on, troubleshoot the PGM-FI system first.
  • Even though the system is operating normally, the EPS indicator will come on caused by detecting condition of the DTC 21-01 or DTC 21-02.

1.Turn the ignition switch OFF.

2.Raise the vehicle, and support it with safety stands in the proper locations, and allow all four wheels to rotate freely.

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

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

5.Check the VEL in the DATA LIST with the HDS.

Is vehicle speed indicated?


YES - The system is OK at this time.n


NO - Go to 6.


6.Check for DTCs in the PGM-FI system (M/T) or A/T system (A/T) with the HDS.

Is DTC P0720, P0721, P0722 or P0723 indicated?


YES - Perform the appropriate troubleshooting for the code indicated.n


NO - Go to 7.


7.Start the engine and check the tachometer.

Is the tachometer working correctly?


YES - Go to 8.


NO - Perform the gauge control module (tach) troubleshooting.n

8.Turn the ignition switch OFF.

9.Disconnect the ECM/PCM connector A (44P) and EPS control unit connector D (28P).

10.Check for continuity between EPS control unit connector D (28P) terminals No. 1 and ECM/PCM connector A (44P) terminals No. 36.

 

Is there continuity?


YES - Go to 11.


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

11.Check for continuity between EPS control unit connector D (28P) terminals No. 15 and ECM/PCM connector A (44P) terminals No. 37.

 

Is there continuity?


YES - Check for loose terminals in the EPS control unit D (28P) connector, and repair if necessary. If no poor connections are found, replace the EPS control unit.n


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