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 C0161 5A: Antilock Brake System (ABS) Brake Sensor Circuit Plausibility Failure

### Circuit/System Description

The electronic brake control module (EBCM) monitors inputs from the brake pressure sensor, wheel speed sensors, and the brake pedal position sensor. When the vehicle is stopping the EBCM monitors for the brake pedal is pressed, with the brake pressure increasing and the vehicle is slowing down, or when the vehicle is accelerating, the brake pedal is not pressed and brake pressure is not increasing.

### Conditions for Running the DTC

The vehicle speed is greater than 16 km/h (10 mph).

### Conditions for Setting the DTC

One of the following conditions exists:

• | The EBCM detects the brake pedal signal is continuously Active for 6 minutes when driving faster than 20 kph (13 mph).

• | The EBCM detects the brake pressure sensor signal indicating a pressure increase but the brake light switch signal is not changing.

• | The EBCM detects 4 times, the vehicle is accelerating to speeds above 40 kph (25 mph) and decelerating down to speeds below 3 kph (2mph) and no change in the brake light switch signal.

### Conditions for Clearing the DTC

• | The condition for the DTC is no longer present.

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

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation Reference

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Connector Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, observe the scan tool EBCM BPP parameter while applying and releasing the brake pedal. The reading should change between Applied and Released.

⇒ | If the parameter does not change between applied and release, replace the EBCM.

2. Replace the BPMV.

### Repair Instructions

Perform the Diagnostic Repair Verificationafter completing the diagnostic procedure.

• | Brake Pressure Modulator Valve Replacement

• | Control Module Referencesfor EBCM replacement, setup, and programming