Diagnostic Instructions

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

DTC Descriptors

DTC C0161 00: Antilock Brake System (ABS) Brake Switch Circuit

DTC C127D: Antilock Brake System (ABS) Brake Switch Circuit

DTC C0161 04: Antilock Brake System (ABS) Brake Switch Circuit Open Circuit

DTC C0161 0E: Antilock Brake System (ABS) Brake Switch Circuit Resistance Below Threshold

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Brake Pedal Switch Ignition Voltage	C0161 04	C0161 04	--	--
Brake Pedal Switch Signal	--	C0161 04	--	C0161 00, C127D, C0161 0E

Circuit/System Description

The brake pedal switch sends a signal to the electronic brake control module (EBCM) when the brake pedal is applied.

Conditions for Running the DTC

C0161 00, C0161 04 or C127D

C0161 0E

Conditions for Setting the DTC

C0161 04

The brake pedal switch is sensed as unapplied while the pressure sensor and travel sensor indicate the brake pedal is applied.

C0161 00, C0161 0E or C127D

The brake pedal is sensed as applied while the vehicle speed is greater than 15 km/h (9 mph).

Action Taken When the DTC Sets

Conditions for Clearing the DTC

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, with a scan tool to observe the EBCM Brake Switch Status parameter while applying and releasing the brake pedal. The reading should change between Applied and Released.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the stop lamp switch.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal B and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test the signal circuit terminal A for a short to ground.

3. Verify the EBCM Brake Switch Status parameter displays Released.

⇒	If not the specified value, test the signal circuit terminal A for a short to voltage. If the circuit tests normal, replace the EBCM.

4. Install a 3A fused jumper wire between the signal circuit terminal A and the ignition circuit terminal B. Verify the scan tool EBCM Brake Switch Status is Applied.

⇒	If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the EBCM.

5. If all circuits test normal, test or replace the stop lamp switch.

Component Testing

1. Ignition OFF, disconnect the harness connector at the stop lamp switch.
2. Test for infinite resistance between the signal terminal A and the ignition terminal B with the switch in the open position.

⇒	If not the specified value, replace the stop lamp switch.

3. Test for less than 1.0 ohms between the signal terminal A and the ignition terminal B with the switch in the closed position.

⇒	If greater than the specified range, replace the stop lamp switch.

4. Install a 3A fused jumper wire between the signal circuit terminal A and the ignition circuit terminal B. Verify the scan tool EBCM Brake Switch Status is Applied.

⇒	If greater than the specified range, replace the stop lamp switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.