GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The EBCM illuminates the TRACTION OFF indicator by supplying ground to the lamp.

Diagnostic Aids

The traction control system can be controlled by the operator in the following ways:

    • Through operation of the traction assist switch on the Instrument Panel Cluster.
    • Through programming of the traction control system's automatic engagement feature.

Depending on the programmed state, the operation of the traction control system (as well as the operation of the TRACTION OFF and LOW TRACTION indicators) will differ. For a more detailed explanation of these operational characteristics, refer to "Traction Assist Indicator Lamps" in ABS Operation .

To determine the status of the traction control system when it is unknown if the system is operational, install a scan tool in the vehicle and observe the following data list parameters:

    • Traction Assist Enabled
    • Traction Off Lamp Command

Press the traction assist switch and observe the scan tool to verify a change in the status of the data list parameters.

Test Description

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

  1. This step tests for proper operation of the TRACTION OFF indicator circuitry.

Step

Action

Value(s)

Yes

No

Schematic Reference: Antilock Brake System Schematics

1

Did you perform the ABS Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check

2

Use a scan tool in order to command the Traction Off Lamp Off.

Does the TRACTION OFF indicator turn off when commanded Off?

--

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn the ignition OFF.
  2. Remove the traction assist switch. Refer to Traction Assist Switch Replacement .
  3. Turn the ignition ON.
  4. Connect a test lamp between the service traction control signal circuit and the ignition 1 voltage circuit at the traction assist switch harness connector.
  5. Use the scan tool in order to command the Traction Off Lamp On and Off.

Does the test lamp turn on and off with each command?

--

Go to Step 5

Go to Step 4

4

Test the service traction control signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 6

5

Inspect for poor connections at the traction assist switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 7

6

Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 8

7

Replace the traction assist switch. Refer to Traction Assist Switch Replacement .

Did you complete the replacement?

--

Go to Step 9

--

8

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 9

--

9

Use the scan tool in order to command the Traction Off Lamp On and Off.

Does the TRACTION OFF indicator turn on and off with each command?

--

System OK

Go to Step 3