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 Descriptors
DTC C0163: Antilock Brake System (ABS)/Traction Control System (TCS) Brake Switch Circuit MalfunctionDTC C0164: Antilock Brake System (ABS)/Traction Control System (TCS) Brake Switch Circuit Malfunction
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
B+ | 1 | 1 | -- | -- |
Stop Lamp Switch Signal | -- | C0163 | C0164 | -- |
1. Stop Lamp Switch Malfunction | ||||
Circuit/System Description
The electronic brake control module (EBCM) monitors the stop lamp switch signal circuit to know when the brake pedal is pressed. The EBCM uses this input for antilock brake system (ABS) functions and HydroMax pump motor control.
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
C0163
The EBCM detects an open in the stop lamp switch signal circuit.
C0164
The EBCM detects a short to voltage in the stop lamp switch signal circuit.
Action Taken When the DTC Sets
| • | The service brake soon indicator illuminates. |
| • | A fast rate audible chime turns ON. |
Conditions for Clearing the DTC
The conditions for setting the DTC are no longer present.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Brake Warning System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool EBCM Brake Switch Status parameter while pressing and releasing the brake pedal. The reading should change between Off and On.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the stop lamp switch.
- Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal B and ground.
- Verify the scan tool EBCM Brake Switch Status parameter is Off.
- Install a 3A fused jumper wire between the signal circuit terminal A and the B+ circuit terminal B. Verify the scan tool EBCM brake switch is On.
- If all circuits test normal, test or replace the stop lamp switch.
| ⇒ | If the test lamp does not illuminate, test the B+ circuit terminal B for a short to ground or an open/high resistance. If the circuit tests normal and the control circuit fuse block I/P Circuit Breaker 25 is open, test the signal circuit terminal for a short to ground. |
| ⇒ | If not the specified value, test the stop lamp switch signal circuit terminal A for a short to voltage. If the circuit tests normal, replace the EBCM. |
| ⇒ | If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the EBCM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the stop lamp switch.
- Test for infinite resistance between the signal terminal A and the control terminal B with the switch in the open position.
- Test for less than 5 ohms between the signal terminal A and the control terminal B with the switch in the closed position.
- Test for infinite resistance between each terminal and the stop lamp switch housing case.
| ⇒ | If not the specified value, replace the stop lamp switch. |
| ⇒ | If greater than the specified range, replace the stop lamp switch. |
| ⇒ | If not the specified value, replace the stop lamp switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for EBCM replacement, setup, and programming |
