GM Service Manual Online
For 1990-2009 cars only

Circuit Description

This DTC identifies a malfunction within the EBCM/EBTCM.

Conditions for Setting the DTC

An internal EBCM/EBTCM malfunction exists.

Action Taken When the DTC Sets

    • A DTC C1255xx is stored
    • Depending on the sub code, the ABS/TCS and/or the Magnasteer® is disabled

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and the scan tool clear DTC function is used
    • 50 ignition cycles have passed with no DTCs detected

Diagnostic Aids

    • Two more numbers will follow the DTC C1255xx on the Scan Tool, which should be noted along with any other DTCs that may be displayed. These two numbers help engineering to determine the cause of the internal malfunction.
    • A DTC C1255e2 can be caused by a battery or module connector disconnect. Inspect for a recent battery disconnect or module connector disconnect before replacing the EBCM/EBTCM.
    • A DTC C1255m5 can be set along with any wheel speed sensor DTC. Diagnose any wheel speed sensor DTCs before replacing the EBCM/EBTCM.
    • Inspect that the EBCM/EBTCM to BPMV connection is secure, tight, and free from corrosion.

Test Description

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

  1. This step checks for damage.

DTC C1255 EBCM/EBTCM Internal Malfunction

Step

Action

Value(s)

Yes

No

1

Was the Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

Are there any other DTCs present besides C1255xx?

--

Go to Diagnostic Trouble Code (DTC) List for Appropriate DTC Table

Go to Step 3

3

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the EBCM/EBTCM.
  3. Inspect for damaged, pushed out, or miswired terminals.

Was any damage found?

--

Go to Step 4

Go to Step 5

4

Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check

--

5

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

Is the replacement complete?

--

Go to Diagnostic System Check

--