For 1990-2009 cars

### 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 Descriptor

DTC C0131 00: Traction Control System Pressure Circuit Malfunction
DTC C0131 4B: Traction Control System Pressure Circuit Calibration Not Learned
DTC C0131 5A: Traction Control System Pressure Circuit Not Plausible

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
5 V Reference | C0131 00 | C0131 00 | C0131 00 | --
Signal | C0131 00 | C0131 00 | -- | C0131 5A

### Circuit/System Description

The brake pressure sensor is integral to the brake pressure modulator valve assembly. The electronic brake control module (EBCM) monitors the brake pressure sensor supply voltage and the signal voltage. The body control module (BCM) sends a serial data message when the brake pedal is applied.

### Conditions for Running the DTC

Ignition ON.

### Conditions for Setting the DTC

#### C0131 00

• | The brake pressure sensor signal is out of the specified range.

• | The brake pressure sensor signal offset is out of the specified range.

#### C0131 5A

• | The EBCM detected an invalid or erratic brake pressure sensor signal.

• | The brake pressure sensor signal is not plausible.

#### C0131 4B

The brake pressure sensor is not calibrated.

### Action Taken When the DTC Sets

• | The EBCM disables the traction control and stability control for the duration of the ignition cycle.

• | The traction control/stability control-active indicator turns ON.

### Conditions for Clearing the DTC

• | A current DTC clears when the diagnostic runs and passes.

• | The EBCM will turn OFF the indicator in the next ignition cycle.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

Ignition ON, observe the scan tool Brake Pressure Sensor parameter. The reading should be 0 V, when the brake pedal is released and greater than 1 V, when the brake pedal is applied.

### Circuit/System Testing

1. Verify that DTC C0131 4B is not present.

⇒ | If DTC C0131 4B is present, perform the Brake Pressure Modulator Valve Pressure Sensor Calibration.

2. Replace the brake pressure modulator valve assembly and verify the DTC does not reset.

⇒ | If the DTC resets replace the K17 Electronic Brake Control Module (EBCM).

### Repair Instructions

• | Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Brake Pressure Modulator Valve Replacement

• | Control Module References for EBCM replacement, setup and programming