Circuit/System Testing

WARNING: This page is about a different car, the 2008 Isuzu i-370, 2008 Isuzu i-290, 2008 GMC Canyon, and 2008 Chevrolet Colorado. However, it is still accessible from the selected car via links, so may be relevant.

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 suspect wheel speed sensor.
Ignition ON, test for 0 volts between the sensor signal circuit terminal 2 and ground.
- If not the specified value, test the sensor signal circuit for a short to voltage. If the circuit tests normal, replace the EBCM.
Disconnect the harness connector at the EBCM.
Test for infinite resistance between the sensor signal circuit terminal 2 and ground.
- If not the specified value, test the sensor signal circuit for a short to ground.
Test for less than 1 ohm of resistance between the sensor signal circuit terminals of the appropriate sensor listed below.
- LF sensor terminals 2 and 26
- RF sensor terminals 2 and 11
- If greater than the specified range, test the low reference circuit for an open/high resistance.
Test for infinite resistance between the supply voltage circuit and ground.
- If not the specified value, test the supply voltage circuit for a short to ground.
Test for less than 1 ohm of resistance between the signal circuit terminals.
- LF sensor terminals 1 and 18
- RF sensor terminals 1 and 12
- If not within the specified range, test the supply voltage circuit for an open/high resistance.
If all circuits test normal, replace the EBCM.