Circuit Description
The brake fluid level switch monitors the level of brake fluid in the master cylinder. When the IPC sees the brake fluid level switch input grounded, it turns ON the red Brake indicator and sends a serial data message to the EBCM that tells the EBCM that the brake fluid level is low.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The EBCM receives a serial data message from the IPC indicating that the brake fluid level is low.
Action Taken When the DTC Sets
| • | The EBCM disables the TCS (w/NW9) for the duration of the ignition cycle. |
| • | The red Brake warning indicator turns ON. |
| • | The Traction Off 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 Warning Lamp parameter is Off? | 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 Warning Lamp parameter is Off? | 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 instrument cluster (IPC). 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 instrument cluster (IPC). Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console. 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 |
