GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Traction Control and Active Handling indicator is controlled by the instrument cluster via serial data messages from the EBCM. When the BCM sees the traction control switch input grounded through the momentary traction control switch, it sends a serial data message to the EBCM that tells the EBCM that the traction control switch has been pressed. The EBCM then disables TCS and VSES (w/JL4). The EBCM sends a serial data message to the instrument cluster to turn the Traction Control and Active Handling indicator ON and display the Traction System Off message or the Traction/Active Handling Off message (w/JL4) on the DIC.

With JL4, when the BCM sees the traction control switch input grounded for 5 seconds while the vehicle is stopped and the ignition is ON, it sends a serial data message to the EBCM that tells the EBCM that the traction control switch has been pressed for 5 seconds. The EBCM then disables TCS, while leaving VSES enabled. The EBCM sends a serial data message to the instrument cluster display the Competitive Driving message on the DIC. The Traction Control and Active Handling indicator remains OFF.

Each time the ignition is cycled from OFF to ON, the TCS and VSES (w/JL4) are enabled.

The following conditions will cause the Traction Control and Active Handling indicator to illuminate:

    • The EBCM has disabled the TCS or VSES due to a DTC.
    • The driver manually disabling the TCS or VSES via the traction control switch.
    • The instrument cluster bulb check. When the ignition switch is turned to ON, the Traction Control and Active Handling indicator will turn on for approximately 3 seconds and then turn OFF.

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

The BCM detects a ground on the traction control switch signal circuit for longer than 60 seconds.

Action Taken When the DTC Sets

    • The ABS remains functional.
    • The ABS indicator remains OFF.

Conditions for Clearing the DTC

    • The condition for the DTC is no longer present (the DTC is not current) and you used the scan tool Clear DTC function.
    • The condition for the DTC is no longer present (the DTC is not current) and you used the On-Board Diagnostics Clear DTC function.
    • The BCM automatically clears the history DTC when a current DTC is not detected in 50 consecutive ignition cycles.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Tests for the normal state of the TCS switch using a scan tool.

  2. Tests if the BCM is able to detect a change in TCS switch state.

  3. Tests for a stuck or shorted TCS switch. If the TCS switch is stuck or shorted, the state will change from On to Off when the TCS switch is disconnected.

  4. Tests for a short to ground in the TCS switch signal circuit.

  5. When the BCM is replaced, use a scan tool to perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views or Body Control System Connector End Views in Body Control System

1

Did you perform the ABS Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - ABS

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the TCS Switch parameter in the BCM data list.

Does the scan tool display Off?

Go to Step 3

Go to Step 4

3

  1. Activate the TCS switch.
  2. With the scan tool, observe the TCS Switch parameter.

Does the TCS Switch parameter change state?

Go to Diagnostic Aids

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the TCS switch.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the TCS Switch parameter.

Does the scan tool display Off?

Go to Step 7

Go to Step 5

5

Test the signal circuit of the TCS switch 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 10

Go to Step 6

6

Inspect for poor connections at the harness connector of the BCM. 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 10

Go to Step 8

7

Inspect for poor connections at the harness connector of the TCS 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 10

Go to Step 9

8

Important: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Step 10

--

9

Replace the traction control switch. Refer to Electronic Traction Control Switch Replacement .

Did you complete the repair?

Go to Step 10

--

10

  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 Step 2

System OK