For 1990-2009 cars only
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using the 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 00: Antilock Brake System (ABS) Brake Switch CircuitCircuit/System Description
The normally-open stop lamp switch supplies battery voltage to the engine control module (ECM) when the brake pedal is pressed. The ECM sends a brake pedal applied serial data message to the electronic brake and traction control module (EBTCM) and to the transmission control module (TCM).
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
| • | The EBCM detects an open in the brake signal circuit. |
| • | Both brake lamps are faulty. |
Action Taken When the DTC Sets
| • | The EBCM stores this information only code DTC for as long as the condition is present. |
| • | The ABS remains functional. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present. |
| • | 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
| • | A signal circuit of the stop lamp switch is open |
| • | The stop lamp switch is improperly adjusted |
| • | All brake lamps are open |
| • | All brake lamp grounds are open |
| • | An open or high resistance in the EBCM ground |
Reference Information
Electrical Information Reference
Scan Tool Reference
Scan Tool Data List for EBCM
Circuit/System Verification
- Apply and release brake pedal. Verify brake lamps operate properly.
- Replace EBCM/brake pressure modulator valve (BPMV) assembly.
| ⇒ | If brake lamps do not operate properly, refer to Diagnostic Starting Point - Lighting Systems . |
Repair Verification
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
