For 1990-2009 cars

### DTC Descriptor

DTC C0161 00: Antilock Brake System (ABS) Brake Switch/Sensor Circuit not Plausible.

### Diagnostic Fault Information

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

### Circuit/System Description

The brake pedal position (BPP) sensor is an input to the body control module (BCM). The BCM then sends a serial data message to the electronic brake control module (EBCM) and other electronic control modules. The BPP sensor is a potentiometer type sensor with a 5-volt reference circuit and a low reference circuit.

### Conditions for Running the DTC

• | The ignition is ON.

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

• | The ignition voltage is greater than 9.5 volts.

### Conditions for Setting the DTC

• | The vehicle speed is greater than 40 km/h (25 mph) and then slow down to less than 3 Km/h (2 mph) 4 times and the brake pedal signal does not show any change in state.

• | The vehicles speed is greater than 20 Km/h (12 mph) and the brake pedal signal indicates an active state for continuously more than 6 minutes.

• | The brake light switch signal coming from the module sends invalid data to the EBCM in terms of the rolling count value.

### Action Taken When the DTC Sets

The ABS/TCS remains functional.

### Conditions for Clearing the DTC

• | The condition for 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 DTC C0161 00 can be set if the vehicle has been driven with the brake applied during acceleration.

### 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 Verification

With the ignition ON, use a scan tool to display DTCs for the BCM.

⇒ | If DTC C0277 or C0890 and C0297 are present, go to Diagnostic System Check - Vehicle .

⇒ | If no DTCs are present, go to Diagnostic Aids.

### Repair Verification

Diagnostic Repair Verification