GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Brakes 🢒 Antilock Brake System 🢒 Traction Off Indicator Always On

Circuit Description

The ignition 3 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

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:

    •  Testing for Electrical Intermittents
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs
    •  Connector Repairs

Test Description

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

  1. This step tests the traction off indicator circuitry. If the fuse in the jumper wire opens when you perform this test, the service traction control circuit is shorted to voltage.

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 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

Observe the Traction Off Lamp Command on the scan tool.

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

Go to Step 9

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the EBCM harness connector.
  3. Turn ON the ignition.
  4. Connect a fused jumper wire between the service traction control signal circuit and a good ground. Refer to Using Fused Jumper Wires in Wiring Systems.

Does the traction off indicator turn OFF?

Go to Step 8

Go to Step 5

5

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

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

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 10

Go to Step 7

7

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

Did you complete the replacement?

Go to Step 10

--

8

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 10

Go to Step 9

9

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

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

Did you complete the replacement?

Go to Step 10

--

10
  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?

System OK

Go to Step 3