GM Service Manual Online
For 1990-2009 cars only

Object Number: 491185  Size: MF
Body Control Module Components
Body Control System Schematics

Circuit Description

The brake fluid level switch is a discrete input to the body control module (BCM). When the brake fluid level becomes low, the level switch closes and grounds the brake fluid level switch input to the BCM (circuit 849).

Conditions for Running the DTC

The ignition switch is on.

Conditions for Setting the DTC

The BCM detects low brake fluid for 2 seconds.

Action Taken When the DTC Sets

The BRAKE indicator illuminates.

Conditions for Clearing the DTC

    • A current DTC C0267 will clear when the BCM detects the proper brake fluid level for at least 2 seconds.
    • All BCM history codes clear after 100 ignition cycles with no current codes active during the 100 ignition cycles.
    • Use a Scan Tool.

Diagnostic Aids

    • Visually inspect the brake fluid level and fill if needed.
    • If the DTC is a history DTC, the problem may be intermittent. Try performing the tests while wiggling the wiring and connectors. This can often cause the malfunction to appear.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. The scan tool displays OFF when the brake fluid level is correct.

  2. The scan tool displays ON when the brake fluid level is low.

  3. The scan tool should display OFF when the brake fluid level switch is disconnected.

Step

Action

Yes

No

1

Did you perform the Hydraulic Brakes Diagnostic System Check?

Go to Step 2

Go to A Diagnostic System Check-Hydraulic Brakes

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the BRAKE FLUID LEVEL SWITCH parameter in the BCM data list.

Does the scan tool display OFF?

Go to Step 3

Go to Step 4

3

  1. Disconnect the brake fluid level switch.
  2. Use a 3-amp fused jumper wire in order to ground terminal B of the brake fluid level switch.
  3. With the scan tool, observe the BRAKE FLUID LEVEL SWITCH parameter.

Does the BRAKE FLUID LEVEL SWITCH parameter change state?

Go to Diagnostic Aids

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Remove the fused jumper wire if installed.
  3. Disconnect the brake fluid level switch.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the BRAKE FLUID LEVEL SWITCH parameter.

Does the scan tool display OFF?

Go to Step 7

Go to Step 5

5

Test the signal circuit of the brake fluid level switch for an open or 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 6

6

Inspect for poor connections at the harness connector of the BCM. Refer to Testing for Intermittent 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 brake fluid level switch. Refer to Testing for Intermittent 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 BCM. Refer to Body Control Module Replacement in Body Control System.

Important: Perform the set up procedure for the BCM. Refer to BCM Programming/RPO Configuration in Body Control System.

Did you complete the replacement?

Go to Step 10

--

9

Replace the brake fluid level switch. Refer to Brake Fluid Level Switch Replacement in Hydraulic Brakes.

Did you complete the replacement?

Go to Step 10

--

10

  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK