Circuit Description
The brake fluid level switch monitors the level of brake fluid in the master cylinder. When the BCM sees the brake fluid level switch input grounded, it sends a serial data message to the IPC requesting illumination of the red Brake indicator.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
Low brake fluid is detected for 2 seconds.
Action Taken When the DTC Sets
The red Brake warning indicator turns ON.
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and the DTC is cleared with a scan tool. |
| • | The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
Diagnostic Aids
Inspect the master cylinder reservoir for the proper brake fluid level.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Brake Warning System Schematics | |||
1 | Did you perform the Hydraulic Brake Diagnostic System Check? | Go to Step 2 | |
2 | Inspect the brake fluid level. Is the brake fluid level OK? | Go to Step 3 | Go to Brake Fluid Loss |
3 |
Does the scan tool indicate that the Brake Fluid Level Switch parameter is OK? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 |
4 |
Does the scan tool indicate that the Brake Fluid Level Switch parameter is OK? | Go to Step 6 | Go to Step 5 |
5 | Test the signal circuit of the brake fluid level switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the brake fluid level switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
8 | Replace the brake fluid level switch. Refer to Brake Fluid Level Indicator Switch Replacement . Did you complete the repair? | Go to Step 10 | -- |
9 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Did you complete the repair? | Go to Step 10 | -- |
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
