Steering Wheel Sensor
WARNING:
Wait at least 60 seconds after disconnecting negative battery cable before servicing SRS. System reserve capacitor maintains SRS voltage for about 60 seconds after battery is disconnected. Servicing SRS before 60-second period may cause accidental air bag deployment and possible personal injury.
NOTE:
Steering wheel angular velocity sensor is an electronic unit using photo-couplers. Clean hands and working environment are recommended to avoid contaminating this component.
- Turn ignition on. Disconnect steering wheel sensor harness connector. See Fig 1 . See STEERING WHEEL SENSOR R & I under REMOVAL & INSTALLATION. Using DVOM, measure voltage between sensor harness connector terminal No. 2 (Blue wire) and ground. See Fig 2 . If 4-8 volts is present, go to 3). If 4-8 volts is not present, go to next step.
- Turn ignition off. Disconnect ECS control unit harness connector. Using ohmmeter, check continuity between control unit harness connector (No. 4) terminal No. 105 and sensor harness connector terminal No. 2 (Blue wire). See Figure and Figure . If continuity exists, replace control unit and retest. If continuity does not exist, inspect and repair circuit as needed.
- Turn ignition off. Using ohmmeter, check continuity between sensor harness connector terminal No. 3 (Black wire) and ground. If continuity exists, go to step 5). If continuity does not exist, disconnect ECS control unit harness connector. See Figure .
- Check continuity between control unit harness connector terminal No. 116 and sensor harness connector terminal No. 3 (Black wire). If continuity exists, replace control unit and retest. If continuity does not exist, inspect and repair circuit as needed.
- Connect steering wheel sensor harness connector. Turn ignition on. Backprobe ECS control unit harness connector between terminal No. 153 and ground, using analog voltmeter. Turn steering wheel back and forth. Voltmeter pointer should pulse between 0-4 volts. Move positive lead of voltmeter to terminal No. 160 and repeat test.
- If either circuit did not operate to specification, go to next step. If both circuits are okay, replace control unit and retest.
- Turn ignition off. Disconnect sensor harness connector. Using ohmmeter, check continuity between ECS control unit harness connector terminal No. 153 and sensor harness connector terminal No. 5 (Green wire). If continuity does not exist, inspect and repair circuit as needed. Repeat step 5). If continuity exists, go to next step.
- Check continuity between control unit harness connector terminal No. 160 and sensor harness connector terminal No. 4 (Yellow/Blue wire). If continuity does not exist, inspect and repair circuit as needed. Repeat step 5). If continuity exists, replace steering wheel sensor and retest.