GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) detects an internal malfunction or loss of ground.

DTC Descriptors

This diagnostic procedure supports the following DTC:

DTC C0550 Electronic Control Unit (ECU) Performance

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom

DTC Symptom Descriptor

00

No Additional Information

04

Open Circuit

Conditions for Running the DTC

The ignition switch is in the ON position.

Conditions for Setting the DTC

C0550 00

An internal EBCM malfunction exists.

C0550 04

System voltage is less than half the ignition voltage continuously for 0.04 seconds.

Action Taken When the DTC Sets

One or more of the following actions may occur:

    • The EBCM disables the ABS system.
    • The EBCM disables or degrades DRP function.
    • The ABS indicator turns ON.
    • The Traction OFF indicator turns ON.
    • The Brake Warning indicator turns ON.

Diagnostic Aids

Possible causes of this DTC:

    • Open ground at the EBCM
    • Internal malfunction in the EBCM

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests for a proper ground to the EBCM.

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

Test the electronic brake control module (EBCM) ground circuits for an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 4

Go to Step 3

3

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming.

Is the replacement complete?

Go to Step 4

--

4

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition and then turn the ignition ON.

Does the DTC reset?

Go to Step 2

System OK