Self-diagnosis Self-diagnosis can be classified into two categories:

- Initial diagnosis: Performed right after the engine starts and until the EPS indicator goes off.
- Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.

The EPS control unit performs the following functions when a problem is detected by self-diagnosis:

1. Turns on the EPS indicator.

1. Memorizes the DTC.

1. Stops power assist and manual steering operation resumes.
   NOTE:
   - When DTC 23 (a problem with the circuit for engine speed signal) is detected, the power assist will return to normal when the vehicle speed is 10 km/h (6 mph) or above.
   - For DTCs 21, 22 and 23 the EPS indicator will go off automatically, and the system returns to normal.