GM Service Manual Online
For 1990-2009 cars only

Object Number: 524882  Size: MF
ABS Components
Antilock Brake System Schematics
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The TRAC OFF indicator is controlled by the instrument cluster via class 2 serial data messages from the EBCM. When the BCM sees the enhanced traction control switch input grounded through the momentary ETS switch, it sends a class 2 message to the EBCM that tells the EBCM that the ETS switch has been pressed. The EBCM then disables the ETS and sends a message to the instrument cluster to turn the TRAC OFF indicator ON. Each time the ignition is cycled from OFF to ON, the ETS is enabled.

Diagnostic Aids

The following conditions will cause the TRAC OFF indicator to illuminate:

    • The EBCM has disabled the ETS due to a DTC.
    • The driver manually disabled the ETS via the ETS switch.
    • The instrument cluster bulb check. When the ignition switch is turned to ON, the TRAC OFF indicator will turn on for approximately 3 seconds and then turn OFF.

Test Description

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

  1. This test ensures that the instrument panel cluster can operate the TRAC OFF indicator.

  2. This test ensures that the BCM is receiving a signal from the ETS switch.

Step

Action

Value(s)

Yes

No

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. Select Special Functions under Instrument Panel Cluster.
  4. With a scan tool, command the warning indicators ON and OFF.

Does the TRAC OFF indicator turn ON and OFF?

--

Go to Step 3

Go to Step 8

3

  1. With a scan tool, select BCM Data.
  2. Monitor the Traction Switch parameter while pressing the ETS switch.

Does the scan tool indicate that the Traction Switch is turning ON and OFF?

--

Go to Step 7

Go to Step 4

4

  1. Disconnect the ETS switch connector.
  2. Test the ETS switch ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Diagnostic System Check - ABS

Go to Step 5

5

  1. Connect a 3 amp fused jumper wire between the signal circuit of the ETS switch and ground.
  2. With a scan tool, observe the Traction Switch parameter in the BCM data list.

Does the scan tool indicate that the Traction Switch is turning ON and OFF?

--

Go to Step 10

Go to Step 6

6

  1. Turn OFF the ignition.
  2. Disconnect the BCM connector C3.
  3. Test the signal circuit of the ETS switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Diagnostic System Check - ABS

Go to Step 7

7

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 Diagnostic System Check - ABS

Go to Step 9

8

Replace the Instrument Panel Cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Did you complete the replacement?

--

Go to Diagnostic System Check - ABS

--

9

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

Did you complete the replacement?

--

Go to Diagnostic System Check - ABS

--

10

Replace the ETS switch.

Did you complete the replacement?

--

Go to Diagnostic System Check - ABS

--