Buick Regal: DTC C0126
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.
- Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descriptor
DTC C0126
Brake Fluid Level Sensor Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
Circuit/System Description
The brake fluid level switch monitors the level of the brake fluid in the
brake fluid reservoir. When the
brake fluid level switch input closed, the electronic brake control module will
set the DTC.
Conditions for Running the DTC
Ignition ON/Vehicle in Service Mode/Vehicle in Service Mode.
Conditions for Setting the DTC
- Low brake fluid level is detected for 5 s.
- An open is detected on the ground circuit.
- An open or short to voltage is detected on the signal circuit.
Action Taken When the DTC Sets
- The electronic brake control module disables the traction control and
stability control for the
duration of the ignition cycle.
- The traction control/stability control-active indicator turns ON.
- The brake warning indicator turns ON.
Conditions for Clearing the DTC
The condition for setting the DTC is no longer present.
Reference Information
Schematic Reference
Hydraulic Brake Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Hydraulic Brake System Description and Operation
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Scan Tool Reference
Refer to Control Module References for scan tool information.
Circuit/System Verification
1. Verify that the brake fluid level is above the minimum level.
Refer to Brake Fluid Loss.
- Go to next step: If above minimum level
2. Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF/Vehicle OFF and all vehicle systems 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.
- Ignition OFF/Vehicle OFF.
- 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.
- Go to next step: If less than 10 Ω
3. Ignition ON/Vehicle in Service Mode.
4. Verify the scan tool Brake Fluid Level Sensor parameter is OK.
- If the parameter is not OK
- Ignition OFF/Vehicle OFF/Vehicle OFF, disconnect the harness connector
at the K17
Electronic Brake Control Module.
- 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.
- Go to next step: If the parameter is OK
5. Ignition OFF/Vehicle OFF.
6. Install a 3 A fused jumper wire between the signal circuit terminal 1 and
ground.
7. Ignition ON/Vehicle in Service Mode.
8. Verify the scan tool Brake Fluid Level Sensor parameter is Low.
- If the parameter is not Low
- Ignition OFF/Vehicle OFF, disconnect the harness connector at the K17
Electronic Brake
Control Module, ignition ON.
- 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.
- Go to next step: If less than 1 V.
- 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.
- Go to next step: If the parameter is Low
9. Test or replace the B20 Brake Fluid Level Switch.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Refer to Control Module References for electronic brake control module
replacement, programming and
setup.
READ NEXT:
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.
Refe
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.
Refe
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.
Refe
SEE MORE:
Warning:
If temperature change or pain to
the skin cannot be felt, the seat
heater may cause burns. To
reduce the risk of burns, use care
when using the seat heater,
especially for long periods of
time. Do not place anything on
the seat that insulates against
heat, such as a blanket, cushion,
cover,
Factors such as maintenance,
temperatures, driving speeds,
vehicle loading, and road conditions
affect the wear rate of the tires.
Treadwear indicators are one way to
tell when it is time for new tires.
Treadwear indicators appear when
the tires have only 1.6mm (1/16 in)
or less of tread remaining