Diagnostic Instructions
DTC Descriptors
DTC C0126 00: Brake Fluid Switch Fault
Circuit/System Description
The instrument panel cluster (IPC) illuminates the BRAKE indicator and sends
a serial data message in order to activate an audible warning when the following occurs,
the IPC detects a low brake fluid condition--signal circuit is low or performs the
displays test at the start of each ignition cycle. The indicator illuminates for approximately
5 seconds. The IPC illuminates the CHECK BRAKE FLUID indicator in the driver information
center (DIC) and sends a serial data message in order to activate an audible warning
when the IPC detects that the brake fluid level is below the normal operating range.
Conditions for Running the DTC
• | Ignition switch is in the ON position. |
• | System voltage is 4 volts. |
Conditions for Setting the DTC
The DTC will set when the IPC detects greater then 4.0 volts from the
brake fluid switch.
Conditions for Clearing the DTC
• | The condition for setting the DTC is no longer present. |
• | The DTC can be cleared using a scan tool. |
Diagnostic Aids
The brake fluid level switch is an integral part of the master cylinder reservoir
and cannot be replaced as an independent component.
Reference Information
Schematic Reference
Instrument Cluster Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
Scan Tool Reference
Control Module References
Circuit/System Testing
- Ensure that there is sufficient fluid in the brake reservoir.
- Ignition OFF, disconnect the harness connector at the brake fluid level
switch.
- Ignition ON, test for voltage between the brake fluid level switch signal
circuit and a known ground.
⇒ | If the voltage is greater than 4.0 volts, test the brake fluid level
switch signal circuit for a short to voltage, if the circuit tests normal replace
the IPC. |
⇒ | If the voltage is less than 4.0 volts, test the brake fluid level switch
signal circuit for a short to ground or an open/high resistance, if the circuit tests
normal replace the IPC. |
- Ignition OFF, test for less than 1 ohm of resistance between the
brake fluid level switch ground circuit and a known ground.
⇒ | If greater than the specified range, test the brake fluid level switch ground
circuit for an open/high resistance. |
- If all circuits test normal, test or replace the brake fluid level switch.
Component Testing
- Ignition OFF, disconnect the harness connector at the brake fluid level
switch.
- Ensure that there is sufficient fluid in the brake reservoir.
- Test for infinite resistance between the brake fluid level switch signal
and ground terminals.
⇒ | If not the specified value, replace the brake fluid level switch. |
Caution: Brake fluid may irritate eyes and skin. In case of contact, take the
following actions:
• | Eye contact--rinse thoroughly with water. |
• | Skin contact--wash with soap and water. |
• | If ingested--consult a physician immediately. |
Notice: Avoid spilling brake fluid on any of the vehicle's painted surfaces,
wiring, cables or electrical connectors. Brake fluid will damage paint and
electrical connections. If any fluid is spilled on the vehicle, immediately
flush the area with water to minimize the potential for damage.
- Siphon the brake fluid out of the master cylinder reservoir using a hand vacuum
pump.
- Test for less than 1 ohm between the brake fluid level switch signal
and ground terminals.
⇒ | If greater than the specified value, replace the brake fluid level switch. |
Repair Instructions
Important: Always perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.