Antilock Brake System - Greater than/Equal to 3900 kg (8600 lb) GVW

DTC C0131 (Greater than or equal to 8600lb GVW)

Diagnostic Instructions

- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC C0131 01: ABS Pressure Circuit Short to Battery
DTC C0131 03: ABS Pressure Circuit Voltage Below Threshold
DTC C0131 06: ABS Pressure Circuit Short to Ground or Open
DTC C0131 0F: ABS Pressure Circuit Erratic
DTC C0131 4B: ABS Pressure Circuit Calibration not Learned
DTC C0131 5A: ABS Pressure Circuit Plausibility Failure
DTC C0131 55: ABS Pressure Circuit Expected Number of Transitions or Events not Reached

Circuit/System Description

The electronic brake control module (EBCM) monitors the brake pressure sensor. The information the EBCM receives from the brake pressure sensor is sent through serial data circuits to the trailer brake control module(TBCM). The TBCM uses this information to perform trailer brake functions. The brake pressure sensor is mounted to the master cylinder.

Conditions for Running the DTC

- The ignition switch is in the ON position.
- Ignition voltage is greater than 9.5 volts.

Conditions for Setting the DTC

- Pressure signal does not correlate to estimated Pressure over time.
- Signal is erratic and changes faster than physically allowed.

Action Taken When the DTC Sets

- The EBCM disables the vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
- A DIC message and/or a warning indicator may be illuminated.

Conditions for Clearing the DTC

- The condition for the DTC is no longer present.
- The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the brake pressure sensor.
2. Ignition OFF, test for less than 5 ohm between the low reference circuit terminal A and ground.
-> If greater than the specified range, test the low reference circuit for an open/high resistance.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B and ground.
-> If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance.
-> If greater than the specified range, test the 5-volt reference circuit for a short to voltage.
4. If all circuits test normal, test or replace the brake pressure sensor. If DTC resets, replace the EBCM.