Circuit/System Testing
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
- Perform a hydraulic check, refer to Brake Hydraulic and Assist System Diagnosis (Two-mode Hybrid) .
- Ignition OFF, disconnect the harness connector at the brake master cylinder piston position sensor.
- Ignition OFF, test for less than 5 Ω between the low reference circuit terminal 1 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 EBCM.
- Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 5 and ground.
- If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.
- If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the EBCM.
- Verify the scan tool BMC Primary Piston Position Sensor A parameter is less than 1 V.
- If greater than the specified range, test the signal circuit terminal 4 for a short to voltage. If the circuit tests normal, replace the EBCM.
- Install a 3A fused jumper wire between the signal circuit terminal 4 and the 5 V reference circuit terminal 5. Verify the scan tool BMC Primary Piston Position Sensor A parameter is greater than 4.5 V.
- 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 EBCM.
- Verify the scan tool BMC Primary Piston Position Sensor B parameter is less than 1 V.
- If greater than the specified range, test the signal circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the EBCM.
- Install a 3A fused jumper wire between the signal circuit terminal 6 and the 5 V reference circuit terminal 5. Verify the scan tool BMC Primary Piston Position Sensor B parameter is greater than 4.5 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 EBCM.
- If all circuits test normal, replace the brake master cylinder pressure sensor.