GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The microprocessor within the EBCM initializes a self-test when the ignition is turned ON.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The microprocessor within the EBCM detects an internal malfunction.

Action Taken When the DTC Sets

C0271 and C0272

    • The ABS indicator is commanded on.
    • The ABS is disabled permanently.

C0273 and C0284

    • The ABS indicator is commanded on.
    • The ABS is disabled for the remainder of the ignition cycle.

Conditions for Clearing the DTC

C0271 and C0272

DTC C0271 and DTC C0272 cannot be cleared from the EBCM memory. The EBCM must be replaced if either of these DTCs is set.

C0273 and C0284

A scan tool is used in order to clear the DTC.

Diagnostic Aids

Replace the EBCM if DTC C0273 or DTC C0284 continues to set intermittently.

Step

Action

Value(s)

Yes

No

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2

Is DTC C0271 or DTC C0272 set in the EBCM memory?

--

Go to Step 4

Go to Step 3

3

  1. Use a scan tool in order to clear the DTC(s).
  2. Turn the ignition OFFfor 5 seconds.
  3. Turn the ignition ON.

Does the DTC set?

--

Go to Step 4

Go to Diagnostic Aids

4

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

Important: Perform the Tire Size Calibration procedure.

Did you complete the replacement?

--

Go to Step 5

--

5

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