Circuit/System Testing
- If the vehicle is equipped with ABS, test the circuit between the EBCM and the ECM for an open/high resistance.
- If the circuit tests normal, refer to Symptoms - Antilock Brake System .
- Ignition OFF, disconnect the harness connector at the rough road sensor.
- Ignition OFF, test for less than 5 ohms of resistance between the low reference circuit terminal A or C and ground.
- If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A or C and ground.
- If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the ECM.
- If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Verify the scan tool rough road sensor voltage parameter is less than 0.1 volt.
- If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Install a 3A fused jumper wire between the signal circuit terminal B and the 5-volt reference circuit erminal A or C. Verify the scan tool rough road sensor parameter is greater than 4.8 volts.
- If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If all circuits test normal, test or replace the rough road sensor.
IMPORTANT:
The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.