Electrical Power Steering (EPS) Signal Circuit Troubleshooting
Electrical Power Steering (EPS) Signal Circuit Troubleshooting1. Turn the ignition switch ON (II).
2. Measure voltage between ECM connector terminals A24 and E16.
Is there battery voltage?
YES - Go to step 6.
NO - Go to step 3.
3. Start the engine.
4. Turn the steering wheel to the full lock position.
5. Measure voltage between ECM connector terminals A24 and E16.
Is there momentary battery voltage?
YES - The EPS signal is OK.
NO - Go to step 10.
6. Turn the ignition switch OFF.
7. Disconnect the EPS control unit 20P connector.
8. Turn the ignition switch ON (II).
9. Measure voltage between EPS control unit terminal No.17 and body ground.
Is there battery voltage?
YES - Substitute a known-good EPS control unit and recheck.
NO - Repair open in the wire between the ECM (E18) and the EPS control unit.
10. Turn the ignition switch OFF.
11. Disconnect the EPS control unit 20P connector.
12. Turn the ignition switch ON (II).
13. Measure voltage between EPS control unit terminal No.17 and the body ground.
Is there battery voltage?
YES - Substitute a known-good EPS control unit and recheck.
NO - Go to step 14.
14. Turn the ignition switch OFF.
15. Disconnect the ECM connector E (31P).
16. Check for continuity between body ground and ECM connector terminal E16.
Is there continuity?
YES - Repair short in the wire between the ECM (E16) and the EPS control unit.
NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.