Circuit/System Testing

Note: It is recommend that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.

Note: Performing Circuit Testing with EBCM connector disconnected and key on will cause U codes to set. Clear DTCs after performing the test.

1. With the ignition OFF, disconnect the wheel speed sensor connector. Ignition ON, Measure for voltage above 7.5 V on the wheel speed sensor signal circuit.
   • If voltage is below 7.5 check for a short to ground, open or replace EBCM.
2. Ignition OFF, disconnect the EBCM connector. With the EBCM connector disconnected and the ignition ON, measure for 0 volt between the wheel speed sensor signal circuit or the wheel speed sensor low reference circuit and ground at the EBCM connector.
   • If over 0 volt, repair short to voltage in the wheel speed sensor signal circuit or the wheel speed sensor supply voltage circuit.
3. With the ignition OFF and the wheel speed sensor harness disconnected, Measure for infinite ohms of resistance between ground and the wheel speed sensor signal and the wheel speed sensor low reference circuit from the EBCM connector.
   • If less than infinite ohms, repair short to ground in the sensor signal or the low reference circuit.
4. Measure for infinite ohms of resistance between the wheel speed sensor signal circuit and the wheel speed low reference circuit at the EBCM connector.
   • If less than infinite ohms, repair short between the wheel speed sensor signal circuit and the wheel speed sensor low reference circuit.
5. If all circuits test normal replace the suspect wheel speed sensor.