C1006

C1006-13-BRAKE FLUID LEVEL INPUT - CIRCUIT OPEN





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Body Control Module (BCM) provides a reference voltage on the brake fluid level signal circuit through a pull-up resistor that is connected to battery voltage. The Brake Fluid Level Switch switches the brake fluid level signal circuit to ground when the fluid level is low. A diagnostic resistor internal to the switch is placed in parallel with the switch.

- When Monitored:
With the ignition on.

- Set Condition:
When the BCM detects that the parallel resistor is not detected in the circuit and the switch is not closed.





Diagnostic Test

1. CHECK FOR ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

2. CHECK THE BRAKE FLUID LEVEL SWITCH FOR CORRECT OPERATION
1. Turn the ignition off.
2. Disconnect the Brake Fluid Level Switch harness connector.
3. Connect a jumper wire between the (B20) Brake Fluid Level Signal circuit and the (Z420) Ground circuit at the Brake Fluid Level Switch harness connector.
4. Turn the ignition on.
5. With the scan tool, read the Brake Fluid Level.

Does the Brake Fluid Level display Low?

Yes

- Replace the Brake Fluid Level Switch. Brake Fluid Level Switch - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

No

- Go To 3

3. CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR VOLTAGE
1. Measure the voltage between ground and the (B20) Brake Fluid Level Signal circuit.

Is the voltage above 10.5 volts?

Yes

- Go To 5

No

- Go To 4

4. CHECK THE (B20) BRAKE FLUID LEVEL SIGNAL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM D harness connector.
3. Measure the resistance of the (B20) Brake Fluid Level Signal circuit between the Brake Fluid Level Switch and BCM D harness connectors.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (B20) Brake Fluid Level Signal circuit for an open.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

No

- Replace the Body Control Module (BCM). Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

5. CHECK THE (Z420) GROUND CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM D harness connector.
3. Measure the resistance of the (Z420) Ground circuit between the BCM D and the Brake Fluid Level Switch harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the open in the (Z420) Ground circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test .

No

- Replace the Body Control Module (BCM). Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test .