C0131
Antilock Brake System
Diagnostic Information and Procedures
DTC C0131
Circuit Description
The master cylinder pressure sensor is a potentiometer located within the BPMV. The master cylinder pressure sensor signal to the EBCM increases as hydraulic pressure in the front brake circuit increases.
Conditions for Running the DTC
- The ignition is ON.
- The VSES sensors have been successfully initialized or the message center has displayed the stability system disabled message due to an unsuccessful initialization attempt. Refer to ABS Description and Operation (W/O JL4) ABS Description and Operation (W/JL4) for a complete explanation of VSES sensor initialization.
- The vehicle is being driven relatively straight and level at a speed greater than 36 km/h (23 mph).
- The transmission is not shifted into neutral or low gear.
- The parking brake is released.
Conditions for Setting the DTC
Any of the following conditions may cause the DTC to set.
- The EBCM detects open master cylinder pressure sensor circuitry.
- The EBCM detects shorted master cylinder pressure sensor circuitry.
- The master cylinder pressure sensor self-test, which occurs at power-up, fails.
- The zero-pressure signal voltage is not within an acceptable range.
- The master cylinder pressure is not within an expected tolerance based on deceleration rate and other data available to the EBCM.
Action Taken When the DTC Sets
- The EBCM disables the VSES.
- The TCS operates with engine torque reduction only.
- The message center displays the service stability system message.
Conditions for Clearing the DTC
The Conditions for Setting the DTC are no longer present and you use the scan tool Clear DTC's function.
Diagnostic Aids
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Electrical Intermittents, Testing for Intermittent and Poor Connections, Wiring Repairs and Connector Repairs in Wiring Systems.
Test Description
The number below refers to the step number on the diagnostic table.
3. This step is required for vehicles equipped with a hydro-boost brake assist system only. If the vehicle being serviced has vacuum assisted brakes, proceed to step 4.
