Brake Warning Indicator Malfunction
Brake Warning Indicator Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
Electronic brake control module (EBCM) monitors the brake fluid level in the brake fluid reservoir. When the fluid within the brake fluid reservoir is below the MIN level, contacts within the brake fluid level switch closes causing the voltage within the signal circuit to drop. The electronic brake control module (EBCM) will detect the voltage drop and will send a serial data message to the instrument cluster commanding the brake warning indicator to illuminate.
Reference Information
Schematic Reference
Hydraulic Brake Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (DH6)
Description and Operation
Brake Warning System Description and Operation Brake Warning System
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References 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 Brake Fluid Loss
• If above minimum level
2. Ignition ON.
3. Observe the scan tool Brake Fluid Level Sensor parameter. The reading should be OK.
• If the parameter is not OK
Refer to Circuit/System Testing
• If the parameter is OK
4. Command the instrument cluster All Indicators ON and OFF with a scan tool, the brake warning indicator should turn ON and OFF while changing between the commanded states.
• If the brake warning indicator does not turn ON and OFF
Replace the P16 instrument cluster.
• If the brake warning indicator turns ON and OFF
5. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the B20 Brake Fluid Level Switch.
2. Test for less than 5 ohms between the ground circuit terminal 2 and ground.
• If 5 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 5 ohms
3. Ignition ON.
4. Verify the scan tool Brake Fluid Level Sensor parameter is Low.
• If the parameter is not low
1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K17 Electronic Brake Control Module.
• If the parameter is low
5. Install a 3 A fused jumper wire between the signal circuit terminal 1 and ground.
6. Verify the scan tool Brake Fluid Level Sensor parameter is OK.
• If the parameter is not OK
1. Ignition OFF, disconnect the harness connector at the K17 Electronic Brake Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V.
3. Test for less than 2 ohms in the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K17 Electronic Brake Control Module.
• If the parameter is OK
7. Test or replace the B20 Brake Fluid Level Switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair
* Brake Fluid Level Indicator Switch Replacement Service and Repair
* Control Module References Control Module References for electronic brake control module and instrument panel cluster replacement, programming and setup.