Initial Inspection and Diagnostic Overview

EPS INDICATOR LIGHT
Under normal conditions, the EPS indicator in the gauge assembly comes on when the ignition switch is turned to the ON position then goes off after the engine is started. This indicates that the bulb and its circuits are operating correctly. If there is any trouble in the system, the EPS indicator turns on during driving, and the power steering assist is turned off. When the EPS indicator comes on, the control unit memorizes the DTC. In this case, the control unit does not activate the EPS system after the engine starts again but it keeps the EPS indicator on. When a problem is detected, the EPS indicator comes on. Under some conditions the indicator stays on until the ignition switch is turned OFF. Under other conditions, however, the indicator goes off automatically when the system returns to normal. For DTCs 23 and 31, the indicator goes off automatically when the system returns to normal. For all other codes, the indicator stays on until the ignition switch is turned OFF. For DTCs 24 and 25, the EPS indicator goes off when the system is OK after the ignition switch is turned from OFF to ON.

DIAGNOSTIC TROUBLE CODE (DTC)
- The lowest DTC is indicated first.
- The DTCs continue blinking until the ignition switch is turned off.
- The DTCs are erased from the control unit when the EPS control unit VBU power supply or connector is disconnected.
- The EPS system can be reset and the control unit's memory can be erased by disconnecting the CLOCK (7.5 A) fuse for more than ten seconds (except DTCs 24 and 25).

SELF DIAGNOSIS:
The CPU (central processing unit) controls the following when it detects a problem during self-diagnosis:
1. Turns the EPS indicator on to alert the driver.
2. Power assist stops, and normal manual steering operation resumes (except DTC 33).
3. The EPS control unit memorizes the diagnostic trouble code (DTC).
4. After the DTC is stored in the control unit, the CPU stops self-diagnosis.

TROUBLESHOOTING:
- Before starting the troubleshooting, clear the DTC by disconnecting the CLOCK (7.5 A) fuse for ten seconds or more, and test-drive the vehicle. Check that the symptom of the trouble appears again, and then troubleshoot. If the problem is an intermittent problem, the system does not become active after the engine starts even though the problem is solved.
- When both EPS indicator and A/T "D" indicator come on, perform the A/T troubleshooting first.
- When the customer's reported problem cannot be verified in the car, ask the customer about the conditions when the EPS indicator came on, then test-drive the car under those conditions, if possible. If the EPS indicator does not come on during the test, check for loose connections or poor contacts at the connectors by wiggling the harness, etc.
- The connector terminal numbers are viewed from the wire side for the female terminals and from the terminal side for the male terminals.
- After the repair, test-drive the car and check that the EPS indicator does not come on again during the test. Please refer to Steering; Testing and Inspection; Procedures; Diagnosis By System; Symptom-to-System Chart for diagnostic period.