• 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.

For symptom byte information refer to Symptom Byte List.

The brake fluid level switch monitors the level of the brake fluid in the brake fluid reservoir. When the electronic brake control module sees the brake fluid level switch input open, the DTC is set.

Ignition ON.

A open or short to battery is detected on the signal circuit.

• The brake warning indicator turns ON.
• ABS indicator turns ON.
• Traction control indicator turns ON.

The condition for setting the DTC is no longer present.

Hydraulic Brake Schematics

Master Electrical Component List

Hydraulic Brake System Description and Operation

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

Control Module References for scan tool information

1. Ignition OFF, disconnect the harness connector at the B20 Brake Fluid Level Switch. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
• If 10 Ω or greater
1. Ignition OFF.
2. Test for less than 2 Ω in the ground circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, repair the open/high resistance in the ground connection.
• If less than 10 Ω
3. Ignition ON.
4. 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.
2. Test for infinite resistance between the signal circuit terminal 1 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 OK
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 Low.
• If the parameter is not Low
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 Ω in the signal circuit end to end.
• If 2 Ω or greater, repair the open/high resistance in the circuit.
• If less than 2 Ω, replace the K17 Electronic Brake Control Module.
• If the parameter is Low
7. Test or replace the B20 Brake Fluid Level Switch.

Perform the Diagnostic Repair Verification after completing the repair.

• Brake Fluid Level Indicator Switch Replacement
• Control Module References for electronic brake control module replacement, programming and setup.