Measure voltage between EPS control unit terminal No. 17 and the body ground. EPS CONTROL UNIT 20P CONNECTOR Wire side of female terminals Is there battery voltage? YES - Substitute a known-good EPS control unit and recheck. NO - Go to step 14. Turn the ignition switch OFF. Disconnect the ECM/PCM connector E (31P). Check for continuity between body ground and ECM/PCM connector terminal E16. ECM/PCM CONNECTORS E (31P) Wire side of female terminals Is there continuity? YES - Repair short in the wire between the ECM/PCM (E16) and the EPS control unit. NO - Substitute a known-good ECM/PCM and recheck (see page 11-6). If prescribed voltage is now available, replace the original ECM.

Check the brake lights. Are the brake lights on without pressing the brake pedal? YES - Inspect the brake pedal position switch (see page 19-10). NO - Go to step 2. Press the brake pedal. Do the brake lights come on? YES - Go to step 3. NO - Go to step 4. Measure voltage between ECM/PCM connector terminals A24 and E22 with the brake pedal pressed. ECM/PCM CONNECTORS Wire side of female terminals Is there battery voltage? YES - The brake pedal position switch signal is OK. NO - Repair open in the wire between the ECM/PCM (E22) and the brake pedal position switch.