GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The electronic brake control module (EBCM) monitors the Antilock Brake System (ABS) control system.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C1223 ECU Performance

Conditions for Running the DTC

DTC C1223 can be set anytime the ignition is in the ON position.

Conditions for Setting the DTC

The electronic brake control module (EBCM) detects a fault within the ABS system.

Action Taken When the DTC Sets

    • The ABS warning indicator turns ON.
    • The traction control and vehicle stability control (VSC) is disabled.
    • The VSC warning indicator turns ON.

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • An ABS system malfunction
    • If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

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

  1. Use the scan tool in order to clear the DTCs.
  2. Turn OFF the ignition.
  3. Turn ON the ignition, with engine OFF.

Does the DTC reset?

Go to Step 2

Go to Symptoms - Antilock Brake System

3

Are any additional DTCs present in addition to C1223?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

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 Symptoms - Antilock Brake System

System OK