GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The solenoid valve coil circuits are supplied with power from the battery when the valve relay is energized. Switched ground is provided by the electronic brake control module (EBCM) to each coil.

This procedure checks whether the left rear inlet and outlet valves are functioning.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

    • DTC C0080 Left Rear Dump Solenoid Circuit Open
    • DTC C0085 Left Rear Hold Valve Circuit Open

Conditions for Running the DTC

    • Vehicle speed is greater than 6 km/h (4 mph) with the brake pedal not applied
        or
    • Vehicle speed is greater than 15 km/h (9 mph) and the brake pedal is actuated.

Conditions for Setting the DTC

    • A valve has failed.
    • A solenoid coil is open or shorted.

Action Taken When the DTC Sets

The antilock brake system (ABS) is disabled, and the ABS warning lamp is turned ON for the remainder of the ignition cycle. The electronic brake force distribution (EBD) is disabled. If the failure is intermittent, the EBCM will enable the system at the next ignition cycle and set a history DTC.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step begins the test of the inlet valve.

  2. This step tests the outlet valve.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Raise and suitably support the vehicle at the corner being tested. Refer to Lifting and Jacking the Vehicle .
  2. Turn the ignition switch to ON.
  3. Install the scan tool to the data link connector (DLC) and select WHEEL REAR LEFT to begin the solenoid tests at that wheel. This will test both the inlet and the outlet valves.
  4. When the scan tool indicates PRESSURE HOLD, depress and hold the brake pedal until the end of the test.
  5. Have an assistant attempt to rotate the wheel.

Can the wheel be rotated?

Go to Step 3

Go to Step 7

3

  1. Maintain pressure on the brake pedal.
  2. When the scan tool indicates PRESSURE INCREASE, have an assistant attempt to rotate the wheel again.

Can the wheel be rotated?

Go to Step 7

Go to Step 4

4

  1. Maintain pressure on the brake pedal.
  2. When the scan tool indicates PRESSURE RELEASE ON, have an assistant attempt to rotate the wheel again.

Can the wheel be rotated?

Go to Step 5

Go to Step 7

5

  1. Release the brake pedal pressure when the scan tool indicates PRESSURE RELEASE OFF.
  2. Clear all DTCs.
  3. Road test the vehicle.

Does the DTC set?

Go to Step 7

Go to Step 6

6

  1. Inspect the wiring harness and connector terminals for an intermittent problem.
  2. Repair any problem found.

Did you find and correct the condition?

Go to Step 8

--

7

Replace the EBCM.

Did you complete the replacement?

Go to Step 8

--

8

  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