GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The traction control system (TCS) warning indicator is controlled by the electronic brake control module (EBCM). The EBCM supplies the ground to the TCS warning indicator control circuit to turn the indicator on. When the TCS warning indicator control circuit is not grounded at the EBCM, the TCS warning indicator remains off. When the EBCM sees the traction control switch voltage go low, it turns the TCS warning indicator on and disables traction control.

Diagnostic Aids

    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
    • Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Poor terminal-to-wiring connections
       - Physical damage to the wiring harness
    • The following conditions may cause an intermittent malfunction:
       - A poor connection
       - Rubbed-through wire insulation
       - A broken wire inside the insulation
    • If an intermittent malfunction exists refer to General Electrical Diagnosis for further diagnosis.

Test Description

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

  1. This step tests for an internal EBCM malfunction.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition.
  2. Disconnect the electronic brake control module (EBCM) electrical connector.
  3. Turn ON the ignition, with the engine OFF.

Is the TCS warning indicator ON?

Go to Step 3

Go to Step 5

3

Test the TCS warning indicator control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 6

Go to Step 4

4

Replace the instrument cluster. Refer to Instrument Cluster Replacement .

Did you complete the replacement?

Go to Step 6

--

5

Replace the EBCM. Refer to Brake Pressure Modulator Valve Assembly Replacement .

Did you complete the replacement?

Go to Step 6

--

6

Operate the system in order to verify the repair.

Did you complete the repair?

System OK

Go to Step 2