GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 Yukon - 2WD 🢒 Brakes 🢒 Antilock Brake System 🢒 Traction Off Indicator Always On

Traction Off Indicator Always On Except Bravada

Circuit Description

The ignition 1 voltage circuit supplies 12 volts to the traction control switch. The EBCM turns OFF the traction off indicator by applying ground to the service traction control signal circuit.

Diagnostic Aids

The traction control system can be controlled by the operator in the following ways:

    • Through operation of the traction control switch.
    • Through programming of the traction control system automatic engagement feature.

Depending on the programmed state, the operation of the traction control system, as well as the operation of the traction off and low traction indicators, differs. For a more detailed explanation of these operational characteristics, refer to Traction Control Indicator Lamps in ABS Description and Operation .

Observe the data list parameters listed below in order to determine the status of the traction control system when it is unknown if the system is operational.

    • Traction Control Enabled
    • Traction Off Lamp Command

Press the traction control switch and observe the scan tool in order to verify a change in the status of the data list parameters.

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Intermittent Conditions and Poor Connections , Wiring Repairs and Connector Repairs in Wiring Systems.

Test Description

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

  1. This step simulates pressing and releasing a properly functioning traction control switch.

    2.

  2. The traction control switch may be damaged if the traction control switch signal circuit is shorted to voltage.

Step

Action

Yes

No

Schematic Reference: Antilock Brake System Schematics

Connector End View Reference: Antilock Brake System Connector End Views

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 for 5 seconds.
  2. Turn ON the ignition while observing the traction off indicator.

Does the traction off indicator illuminate for 3 seconds and then turn OFF?

Go to Diagnostic Aids

Go to Step 3

3

Press and release the traction control switch.

Does the traction off indicator turn OFF?

Go to Diagnostic Aids

Go to Step 4

4
  1. Install a scan tool.
  2. Select the Traction Assist Data Display function on the scan tool.
  3. Press and release the traction control switch while observing the Traction Control Enabled status.

Does the Traction Control Enabled status change?

Go to Step 5

Go to Step 7

5
  1. Turn ON the traction control system by verifying the scan tool displays Traction Control Enabled - Yes.
  2. Observe the Traction Off Lamp Command on the scan tool.

Does the scan tool display Traction Off Lamp Command - On?

Go to Step 13

Go to Step 6

6

Important: Do not disconnect the traction control switch harness connector during this step. Ensure the ignition is turned ON for the duration of this step.

  1. Access the traction control switch harness connector. Refer to Electronic Traction Control Switch Replacement .
  2. Backprobe the traction control switch harness connector in order to connect a test lamp between the ignition 1 voltage circuit and the service traction control signal circuit. Refer to Probing Electrical Connectors in Wiring Systems.

Does the test lamp illuminate?

Go to Step 9

Go to Step 8

7

Important: Do not disconnect the traction control switch harness connector during this step.

  1. Access the traction control switch harness connector. Refer to Electronic Traction Control Switch Replacement .
  2. While observing the Traction Control Enabled status on the scan tool, backprobe the traction control switch harness connector with a test lamp connected to a good ground in order to momentarily contact the traction control switch signal circuit. Refer to Probing Electrical Connectors in Wiring Systems.

Does the Traction Control Enabled status change?

Go to Step 11

Go to Step 10

8

Test the service traction control signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 12

9

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 14

Go to Step 11

10

Test the traction control switch signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

11

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

Did you complete the replacement?

Go to Step 14

--

12

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 14

Go to Step 13

13

Important: Following EBCM replacement, use the scan tool to perform the Tire Size Calibration procedure.

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

Did you complete the replacement?

Go to Step 14

--

14

Press and release the traction control switch several times.

Does the traction off indicator turn ON and OFF each time the switch is pressed?

System OK

Go to Step 2