GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The ignition 1 voltage circuit supplies power to the TRACTION OFF indicator. 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 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 numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for power at the traction assist switch. The IGN1 fuse supplies power to the traction assist switch.

  2. This step verifies that the EBCM is providing ground to the TRACTION OFF indicator.

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 On and Off.

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

--

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 ignition 1 voltage circuit (at the traction assist switch harness connector) and a good ground.

Does the test lamp illuminate?

--

Go to Step 4

Go to Step 8

4

  1. Connect a test lamp between the ignition 1 voltage circuit and the service traction control signal circuit at the traction assist switch harness connector.
  2. 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 6

Go to Step 5

5

Test the service traction control signal circuit an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 11

Go to Step 7

6

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 11

Go to Step 9

7

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 11

Go to Step 10

8

Repair the open in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 11

--

9

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

Did you complete the replacement?

--

Go to Step 11

--

10

Important: Perform the Tire Size Calibration procedure.

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

Did you complete the replacement?

--

Go to Step 11

--

11

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