GM Service Manual Online
For 1990-2009 cars only

DTC C0163 or C0164 C6,C7

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 Malfunction

DTC 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

Stop lamp switch control

1

1

--

--

Stop lamp switch signal

--

C0163

C0164

--

1. Stop Lamp Switch Malfunction

Circuit/System Description

The stop lamp switch input informs the electronic brake control module (EBCM) when the brake is pressed. The EBCM uses this input for antilock brake system (ABS) enhancement and HydroMax pump motor control.

Conditions for Running the DTC

C0163

The vehicle accelerates from 0 km/h (0 mph) to 37 km/h (23 mph).

C0164

The vehicle performs 3 consecutive stops from at least 37 km/h (23 mph) to 0 km/h (0 mph) during a single ignition cycle.

Conditions for Setting the DTC

The EBCM detects an open or shorted stop lamp switch or stop lamp switch signal circuit.

Action Taken When the DTC Sets

C0163

The EBCM stores an information only DTC as a current DTC until the ignition is turned OFF or the EBCM detects an open stop lamp switch.

C0164

    • 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.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool EBCM Brake Switch parameter while pressing and depressing the brake. The reading should change between Off (open switch value) and On (closed applied switch value).

Circuit/System Testing

  1. Ignition OFF, disconnect the EBCM harness connector at the stop lamp switch.
  2. Ignition ON, verify that a test lamp illuminates between the control circuit terminal B and ground.
  3. If the test lamp does not illuminate, test the control 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 1 is open, test the signal circuit terminal for a short to ground.
  4. Verify the scan tool EBCM Brake Switch Status parameter is On.
  5. 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.
  6. Install a 3A fused jumper wire between the signal circuit terminal A and the control circuit terminal B. Verify the scan tool EBCM brake switch is On.
  7. If not the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the EBCM.
  8. 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 circuit terminal A and the control circuit terminal B with the switch in the open position.
  3. If not the specified value, replace the stop lamp switch.
  4. Test for less than 5 ohms between the signal circuit terminal A and the control circuit terminal B with the switch in the closed position.
  5. If greater than the specified range, replace the stop lamp switch.
  6. Test for infinite resistance between each terminal and the stop lamp switch housing case.
  7. If not the specified value, replace the stop lamp switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Stop Lamp Switch Replacement
    •  Control Module References for EBCM replacement, setup, and programming

DTC C0163 or C0164 C4

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 Malfunction

DTC 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

Stop lamp switch control

1

1

--

--

Stop lamp switch signal

--

C0163

C0164

--

1. Stop Lamp Switch Malfunction

Circuit/System Description

The stop lamp switch input informs the electronic brake control module (EBCM) when the brake is pressed. The EBCM uses this input for antilock brake system (ABS) enhancement and HydroMax pump motor control.

Conditions for Running the DTC

C0163

The vehicle accelerates from 0 km/h (0 mph) to 37 km/h (23 mph).

C0164

The vehicle performs 3 consecutive stops from at least 37 km/h (23 mph) to 0 km/h (0 mph) during a single ignition cycle.

Conditions for Setting the DTC

The EBCM detects an open or shorted stop lamp switch or stop lamp switch signal circuit.

Action Taken When the DTC Sets

C0163

The EBCM stores an information only DTC as a current DTC until the ignition is turned OFF or the EBCM detects an open stop lamp switch.

C0164

    • 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.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool EBCM Brake Switch parameter while pressing and depressing the brake. The reading should change between Off (open switch value) and On (closed applied switch value).

Circuit/System Testing

  1. Ignition OFF, disconnect the EBCM harness connector at the stop lamp switch.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground.
  3. If the test lamp does not illuminate, test the B+ circuit terminal E for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse block I/P Fuse 1 is open, test the signal circuit terminal F for a short to ground.
  4. Verify the scan tool EBCM Brake Switch Status parameter is On.
  5. If not the specified value, test the stop lamp switch signal circuit terminal F for a short to voltage. If the circuit tests normal, replace the EBCM.
  6. Install a 3A fused jumper wire between the B+ circuit terminal E and the signal circuit terminal F. Verify the scan tool EBCM brake switch status is On.
  7. If not the specified value, test the B+ circuit terminal E for an open/high resistance. If the circuit tests normal, replace the EBCM.
  8. 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 circuit terminal F and the B+ circuit terminal E with the switch in the open position.
  3. If not the specified value, replace the stop lamp switch.
  4. Test for less than 5 ohms between the signal circuit terminal F and the B+ circuit terminal E with the switch in the closed position.
  5. If greater than the specified range, replace the stop lamp switch.
  6. Test for infinite resistance between each terminal and the stop lamp switch housing case.
  7. If not the specified value, replace the stop lamp switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Stop Lamp Switch Replacement
    •  Control Module References for EBCM replacement, setup, and programming