GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) learns the model options that it is installed in by using the Vehicle ID information from the powertrain control module (PCM) via the class 2 serial data line. Each time the vehicle is in the RUN position the PCM communicates this information via class 2. The EBCM internally compares the VIN and option information with that information stored in the PCM.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0551 Option Configuration Error

Condition for Running the DTC

    • The EBCM detects digit 2-9 of the VIN, and is not zeros.
    • The condition must occur when the ignition switch is first turned on.

Conditions for Setting the DTC

    • The EBCM detects information from the PCM that the options are incorrect, automatic or manual transmission.
    • The condition must occur when the ignition switch is first turned on.

Action Taken When the DTC Sets

If equipped, the following actions occur:

    • The EBCM disables the ABS/traction control system (TCS) for the duration of the ignition cycle.
    • A DTC malfunction will set.
    • The ABS indicator turns
    • The traction control indicator turns ON.
    • The red brake warning light turns ON.

Conditions for Clearing the DTC

    • The EBCM recognizes that information from the PCM is valid information, automatic or manual transmission.
    • A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Diagnostic Aids

DTC C0551 is set when the EBCM detects a mismatch between itself and the programmed PCM in the vehicle by monitoring the PCM class 2 message.

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

Are any other DTCs present besides DTC C0551?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3

Replace the electronic brake control module (EBCM). Refer to Control Module References .

Did you complete the repair?

Go to Step 4

--

4

  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