GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Traction Off message on the DIC is controlled by the instrument cluster via serial data messages from the EBCM. When the EBCM sees the traction control switch input grounded through the momentary traction control switch, it disables traction control and sends a message to the instrument cluster to turn ON the Traction Off message on the DIC. Each time the ignition is cycled from OFF to ON, the traction control system is enabled.

Step

Action

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 - ABS

2

  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the TCS On/Off Status parameter in the Delco/Bosch ABS/TCS ICCS (if equipped) data list.
  5. Activate the traction control switch.

Does the TCS On/Off Status parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Does the scan indicate that the TCS On/Off Status parameter is On?

Go to Step 4

Go to Step 5

4

  1. Turn OFF the ignition.
  2. Disconnect the traction control switch connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the TCS On/Off Status parameter.

Does the scan tool display Off?

Go to Step 10

Go to Step 6

5

  1. Turn OFF the ignition.
  2. Disconnect the traction control switch connector.
  3. Connect a 3 amp fused jumper from the signal circuit of the traction control switch to the ground circuit of the traction control switch.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the TCS On/Off Status parameter.

Does the scan tool display On?

Go to Step 10

Go to Step 7

6

Test the signal circuit of the traction control 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 13

Go to Step 9

7

Test the signal circuit of the traction control 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 Step 13

Go to Step 8

8

Test the ground circuit of the traction control 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 Step 13

Go to Step 9

9

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 13

Go to Step 11

10

Inspect for poor connections at the harness connector of the traction control 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 13

Go to Step 12

11

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

Did you complete the replacement?

Go to Step 13

--

12

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

Did you complete the replacement?

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2