GM Service Manual Online
For 1990-2009 cars only

Object Number: 585744  Size: LF
ABS Components
Antilock Brake System Schematics
Data Link Connector Schematics
Ground Distribution Schematics
Interior Lights Schematics
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

The Body Control Module (BCM) receives the input from the Traction Control Switch. The BCM then sends a class 2 message to the EBCM telling the EBCM the state of the switch. The BCM supplies voltage to the TCS switch and when the TCS switch is depressed the BCM sees the voltage go low and sends the EBCM the message that the TCS switch state has changed. When the EBCM receives the message from the BCM that the switch state has changed it turns on or off Traction Control and its TRAC OFF indicator depending on its previous state.

Diagnostic Aids

    • It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
    • Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
       - Backed out terminals
       - Improper mating
       - Broken locks
       - Improperly formed or damaged terminals
       - Poor terminal-to-wiring connections
       - Physical damage to the wiring harness
    • The following conditions may cause an intermittent malfunction:
       - A poor connection
       - Rubbed-through wire insulation
       - A broken wire inside the insulation
    • If an intermittent malfunction exists refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Traction Off Indicator Inoperative with No DTC Set

Step

Action

Value(s)

Yes

No

DEFINITION: The TRAC OFF indicator does not come on when the Traction Control Switch is pressed to disable the Traction 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. Select Body Control Module Data List in the scan tool listing.
  4. Using the scan tool, read the TCS Switch state as you press and release the TCS Switch.

Does the TCS Switch state change properly as the switch is pressed and released?

--

Go to Step 3

Go to Step 7

3

Using a scan tool in ABS/TCS read the TCS Switch Status as you press and release the TCS Switch.

Does the TCS Switch state change properly as the switch is pressed and released?

--

Go to Step 5

Go to Step 4

4

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

Did you complete the repair?

--

Go to Step 14

--

5

  1. Go to Output Controls in the Instrument Panel display of the scan tool.
  2. Use the WOW mode to turn ON and OFF all of the instrument panel indicators.
  3. The TRAC OFF indicator should turn ON and then OFF when commanded so.

Will the scan tool command the TRAC OFF indicator ON then OFF?

--

Go to Step 4

Go to Step 6

6

Suspect the Instrument Panel Cluster. Refer to Instrument Cluster Diagnostic System Check in Instrument Panel, Gauges and Console.

Did you complete the repair?

--

Go to Step 14

--

7

  1. Disconnect the Traction Control Switch connector.
  2. Using a scan tool in the Body Control Module Data List read the TCS switch status.
  3. Connect a jumper wire between the traction control input circuit and the traction control ground circuit terminal of the Traction Control Switch harness connector.

Does the TCS Switch status change with the jumper wire connected?

--

Go to Step 8

Go to Step 9

8

Replace the Traction Control Switch. Refer to Traction Control Switch Replacement.

Did you complete the repair?

--

Go to Step 14

--

9

  1. Turn OFF the ignition.
  2. Measure the resistance of the traction control ground circuit between the Traction Control Switch harness connector and a known good ground.

Is the resistance within the range specified in the value(s) column?

0-2 ohms

Go to Step 11

Go to Step 10

10

Repair the traction control ground circuit for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

11

  1. Disconnect the Body Control Module connector C2.
  2. Measure the resistance traction control input circuittraction control ground circuit between the Traction Control Switch harness connector and the Body Control Module Connector.

Is the resistance within the range specified in the value(s) column?

0-2 ohms

Go to Step 13

Go to Step 12

12

Repair the traction control ground circuit for an open or high resistance. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 14

--

13

Suspect the Body Control Module. Refer to Body Control Module Diagnostic System Check in Body Control System.

Did you complete the repair?

--

Go to Step 14

--

14

  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