GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Traction Off indicator is controlled by the instrument panel cluster (IPC) via serial data messages from the electronic brake control module (EBCM). When the heater and air conditioning (A/C) control (w/C67) or the instrument panel module (IPM) (w/CJ2) 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 traction control and sends a message to the IPC to turn the Traction Off indicator ON. Each time the ignition is cycled from OFF to ON, the traction control system (TCS) is enabled.

The following conditions will cause the Traction Off indicator to illuminate:

    • The EBCM has disabled the TCS due to a DTC.
    • The driver manually disabling the TCS via the traction control switch.
    • The IPC bulb check. When the ignition switch is turned to ON, the Traction 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. Use the scan tool to check the normal state of the Traction Off indicator control.

  2. Ensures that the instrument cluster can operate the Traction Off indicator.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views , HVAC Connector End Views in HVAC Systems - Automatic, or Instrument Panel, Gages, and Console Connector End Views in Instrument Panel, Gages, and Console

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 Warning Indicator/Message parameter in the DRP/ABS/TCS data list.

Does the scan tool display Off?

Go to Step 3

Go to Step 13

3

  1. Turn OFF the ignition.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Traction Off indicator on the instrument cluster (IPC) during the bulb check.

Does the Traction Off indicator illuminate during the bulb check and then turn OFF?

Go to Step 4

Go to Step 14

4

  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 Switch parameter in the Climate Control Panel (w/C67) data list or the Instrument Panel Module (w/CJ2) data list.
  5. Activate the traction control switch.

Does the TCS Switch parameter change state?

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

Go to Step 5

5

Does the scan indicate that the TCS Switch parameter is On?

Go to Step 6

Go to Step 7

6

  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 Switch parameter.

Does the scan tool display Off?

Go to Step 12

Go to Step 8

7

  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 Switch parameter.

Does the scan tool display On?

Go to Step 12

Go to Step 9

8

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 19

Go to Step 11

9

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 19

Go to Step 10

10

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 19

Go to Step 11

11

Inspect for poor connections at the harness connector of the heater and A/C control (w/C67) or the instrument panel module (IPM) (w/CJ2). 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 19

Go to Step 15

12

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 19

Go to Step 16

13

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 19

Go to Step 17

14

Inspect for poor connections at the harness connector of the instrument cluster (IPC). 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 19

Go to Step 18

15

Replace the heater and A/C control (w/C67) or the instrument panel module (IPM) (w/CJ2). Refer to Instrument Panel Module Replacement in Body Control System

Did you complete the replacement?

Go to Step 19

--

16

Replace the traction control switch. Refer to Shift Lever Replacement in Steering Wheel Column.

Did you complete the replacement?

Go to Step 19

--

17

Important: Perform the setup procedure for the EBCM. An unprogrammed EBCM will result in the following conditions:

   • Inoperative or poorly functioning system operations
   • The EBCM sets DTC C1248 and DTC C1255m3

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

Did you complete the repair?

Go to Step 19

--

18

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

Did you complete the repair?

Go to Step 19

--

19

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2