EPS DTC Troubleshooting: 21-01, 21-02
DTC 21-01:
 Excessive Charge of the Vehicle Speed Signal (Regular diagnosis)
DTC 21-02:
 Comparison between the Engine 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 the detecting condition of DTC 21-01 or DTC 21-02.
  1. Turn the ignition switch to LOCK (0).
  1. Connect the HDS to the data link connector (DLC).
  1. Start the engine, run the vehicle in the 4th gear.
  1. Check the VEL 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 .
  1. Check for DTCs in the PGM-FI system with the HDS.
Is DTC P0720 indicated?
YES -
Troubleshoot the indicated DTC.■
NO -
Go to Step 7 .
  1. Start the engine and check the tachometer.
Is the tachometer working correctly?
YES -
Go to Step 8 .
NO -
  1. Turn the ignition switch to LOCK (0).
  1. Disconnect EPS control unit connector D (28P).
  1. Short the SCS line with the HDS.
  1. Disconnect ECM connector A (49P) (L13Z1 engine model) or ECM connector A (44P) (except L13Z1 engine model).
  1. Check for continuity between EPS control unit connector D (28P) terminal No. 1 and ECM connector A (49P) terminal No. 3 (L13Z1 engine model) or ECM connector A (44P) terminal No. 36 (except L13Z1 engine model).
Is there continuity?
YES -
Go to Step 13 .
NO -
Repair open in the wire between the EPS control unit and ECM.■
  1. Check for continuity between EPS control unit connector D (28P) terminal No. 15 and ECM connector A (49P) terminal No. 4 (L13Z1 engine model) or ECM connector A (44P) terminal No. 37 (except L13Z1 engine model).
Is there continuity?
YES -
Check for loose terminals in the EPS control unit connector D (28P), and repair if necessary. If no poor connections are found, replace the EPS control unit. ■
NO -
Repair open in the wire between the EPS control unit and the ECM.■