For 1990-2009 cars

### DTC Descriptor

DTC C0131 00: ABS Pressure Circuit No Additional Information
DTC C0131 4B: ABS Pressure Circuit Calibration Not Learned
DTC C0131 5A: ABS Pressure Circuit Calibration Not Learned Plausibility Failure

### Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
ABS Pressure Circuit | C0131 00 | C0131 00 | C0131 00 | --
Pressure Circuit Calibration Not Learned | -- | -- | -- | C0131 4B
Pressure Circuit Calibration Not Learned Plausibility Failure | -- | -- | -- | C0131 5A

### Circuit/System Description

The electronic brake control module (EBCM) uses input from the brake pressure sensor for more accurate control during a Vehicle Stability Enhancement System (VSES) event.

### Conditions for Running the DTC

• | The ignition is ON.

• | Ignition voltage is greater than 9.5 volts

### Conditions for Setting the DTC

• | Pressure signal does not correlate to estimated pressure over time.

• | Brake signal does not correlate to pressure signal.

• | Signal is erratic and changes faster than physically allowed.

### Action Taken When the DTC Sets

• | The EBCM disables the VSES and TCS for the duration of the ignition cycle.

• | The electronic stability control (ESC) telltale turns ON.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present and the DTC is cleared with a scan tool.

• | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

### Diagnostic Aids

The pressure sensor is integral to the brake pressure modulator valve (BPMV). The pressure sensor is not serviceable.

Inspect the brake pressure sensor contacts for proper connections.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Antilock Brake System Connector End Views

#### Description and Operation Reference

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Scan Tool Data List for EBCM

### Circuit/System Testing

1. Apply and release brake pedal. Verify brake lamps operate properly.

⇒ | If brake lamps do not operate properly, refer to Symptoms - Lighting Systems .

2. Replace EBCM/brake pressure modulator valve (BPMV) assembly.

### Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Electronic Brake Control Module Replacement

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

### Repair Verification

Diagnostic Repair Verification