Vauxhall Workshop Service and Repair Manuals

Brake Warning Indicator Malfunction

Diagnostic Instructions

Diagnostic Fault Information

Circuit/System Description

The instrument cluster turns ON the brake warning indicator for 5 second after ignition ON. The body control module (BCM) monitors the handbrake switch and will request the instrument cluster via serial data to turn the brake warning indicator ON when the handbrake is applied. When the electronic brake control module (EBCM) detects a fault, it sends a serial data message to the instrument cluster commanding the indicator ON.

Reference Information

Schematic Reference

Hydraulic Brake Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Hydraulic Brake System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Inspect for proper brake fluid level. The fluid level should be above minimum level.

⇒	If low, refer to Brake Fluid Loss .

2. Ignition ON, with a scan tool command the instrument cluster All Indicators test ON and OFF. Verify the brake warning indicator turns ON and OFF.

⇒	If the brake warning indicator does not turn ON and OFF, replace the P16 instrument cluster.

3. Observe the scan tool BCM Park Brake Switch parameter while applying and releasing the handbrake. Verify the reading changes between Active and Inactive.

⇒	If the parameter does not change between the specified values, refer to Park Brake Switch Malfunction.

4. Release the handbrake. Verify the brake warning indicator turns OFF.

⇒	If the brake warning indicator does not turn OFF, refer to Brake Fluid Level Switch Malfunction.

Circuit/System Testing

Note:  Circuit/System Verification must be performed before Circuit/System Testing.

Park Brake Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the B80 handbrake switch.
2. Inspect the B80 handbrake switch for physical damage and correct installation.

⇒	If physical damage or incorrect installation is diagnosed, repair or replace the B80 handbrake switch.

3. Ignition ON, verify the scan tool BCM Handbrake Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.

4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
5. Verify the scan tool BCM Handbrake Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

6. If all circuits test normal, test or replace the B80 handbrake switch.

Brake Fluid Level Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the B20 brake fluid level switch.
2. Test for less than 5 Ω between the ground circuit terminal 2 and ground.

⇒	If greater than the specified value, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool Brake Fluid Level Sensor parameter is Low.

⇒	If not the specified value, test the signal circuit for a short to ground. If the circuit tests normal, replace the K17 EBCM.

4. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
5. Ignition OFF, ignition ON, verify the scan tool Brake Fluid Level Sensor parameter is OK.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K17 EBCM.

6. If all circuits test normal, test or replace the B20 brake fluid level switch.

Component Testing

Park Brake Switch Test

1. Ignition OFF, disconnect the harness connector at the B80 handbrake switch.
2. Test for infinite resistance between the signal terminal 1 and the ground with the parking brake released.

⇒	If less than the specified value, replace the B80 handbrake switch.

3. Test for less than 5 Ω between the signal terminal 1 and the ground with the park brake applied.

⇒	If greater than the specified value, replace the B80 handbrake switch.

Brake Fluid Level Switch Test

1. Ignition OFF, disconnect the harness connector at the B20 brake fluid level switch.
2. Test for less than 5 Ω between the ground terminal 2 and the signal terminal 1.

⇒	If less than the specified value, replace the B20 brake fluid level switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.