Circuit/System Testing

IMPORTANT: It is recommended that Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors because the module will default and does not supply voltage to the sensor when the DTC is set.
Performing Circuit Testing with EBCM connector disconnected and key on will cause U codes to set. Clear DTCs after performing the test.

Ignition OFF, disconnect the harness connector at the EBCM.
Ignition ON, test for 0 volts between the low reference circuit terminals of the appropriate sensor listed below and ground.
- LF Sensor circuit terminal 34
- RF Sensor circuit terminal 6
- If not the specified value, test the low reference circuit for a short to voltage. If the circuit tests normal, replace the wheel speed sensor.
Test for 0 volts between the signal circuit terminals of the appropriate sensor listed below and ground.
- LF Sensor circuit terminal 21
- RF Sensor circuit terminal 18
- If not the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the wheel speed sensor.
Ignition OFF, test for infinite resistance between the low reference terminals of the appropriate sensor listed below and ground.
- LF Sensor circuit terminal 34
- RF Sensor circuit terminal 6
- If not the specified value, test the low reference circuit for a short to ground. If the circuit tests normal, replace the wheel speed sensor.
Test for infinite resistance between the following signal circuit terminals of the appropriate sensor listed below and ground.
- LF Sensor circuit terminal 21
- RF Sensor circuit terminal 18
- If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the wheel speed sensor.
Ignition OFF, disconnect the harness connector at the wheel speed sensor.
Test for less than 1 ohm of resistance between the low reference terminals of the appropriate sensor listed below.
- LF Sensor circuit terminals 34 and 2
- RF Sensor circuit terminals 6 and 2
- If not within the specified range, test the low reference circuit for an open/high resistance.
Test for less than 1 ohm of resistance between the following signal circuit terminals of the appropriate sensor listed below.
- LF Sensor circuit terminals 21 and 1
- RF Sensor circuit terminals 18 and 1
- If not within the specified range, test the signal circuit for an open/high resistance.
Test for infinite resistance between the low reference circuit and the signal circuit of the appropriate sensor listed below and ground.
- LF Sensor circuit terminal 34 and 21
- RF Sensor circuit terminal 6 and 18
- If not the specified value, test the appropriate circuit for a short together.
If all circuits test normal, replace the EBCM.