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

    • There is a solenoid short to battery inside the BPMV. If DTCs C1261-C1274 are set along with DTC C1256xx, pursue the solenoid DTCs first.
    • There is an internal EBCM/EBTCM malfunction.

Action Taken When the DTC Sets

    • A malfunction DTC is stored.
    • The ABS/TCS is not disabled.
    • The ABS and the TRACTION OFF indicators are not turned ON.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present and you used the scan tool Clear DTC function.
    • The EBCM/EBTCM does not detect the DTC in 50 drive cycles.

Diagnostic Aids

    • Two more numbers will follow the DTC C1256xx on the scan tool. Remember these numbers along with any other DTCs that may be displayed. These 2 numbers help engineering in order to determine the cause of the internal malfunction.
    • Verify that the EBCM/EBTCM to BPMV connection meets the following conditions:
       - The connection is secure.
       - The connection is tight.
       - The connection is free from corrosion.

Test Description

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

  1. This step tests for damage.

Step

Action

Value(s)

Yes

No

1

Was the ABS Diagnostic System Check performed?

--

Go to Step 2

Go to Diagnostic System Check - ABS

2

Are there any valve DTCs present (C1261-C1274)?

--

Go to Diagnostic Trouble Code (DTC) List

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 needed. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--

5

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

Is the repair complete?

--

Go to Diagnostic System Check - ABS

--