GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The UHFB supplies the solenoid circuits with battery voltage when the ignition is in the RUN position. The ABS control module (EBTCM) controls the valve function by grounding the solenoid circuit when necessary.

The #1 solenoids are prime valves. The #2 solenoids are isolation valves.

Conditions for Running the DTC

The ignition is turned ON.

Conditions for Setting the DTC

The DTC will set if the ABS control module detects an open, short to ground or short to voltage on the solenoid circuits inside the control module.

Action Taken When the DTC Sets

    • The ABS telltale will be ON.
    • The ABS control module will disable the ABS, the TCS, and the DRP.

Conditions for Clearing the DTC

The condition for the DTC is no longer present and the DTC is cleared with a scan tool.

Diagnostic Aids

The ABS control module must be replaced.

Step

Action

Yes

No

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

2

Use a scan tool in order to clear the DTCs.

Can the DTC be cleared?

Go to Step 3

Go to Step 4

3

Start the engine and allow the engine to idle.

Does the DTC reset?

Go to Step 4

Go to Diagnostic Aids

4

Important: New ABS control modules will automatically set DTC C0551 when installed. To clear DTC C0551, new modules must be configured with the correct engine and transmission option bit. Refer to "ABS Programming" on the Scan tool.

Replace the EBCM. Refer to Electronic Brake Control Module Replacement .

Did you complete the replacement?

Go to Step 5

--

5

  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 3

System OK