GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2005 🢒 TopKick C-Series Commercial (Cutaway) C4/C5 🢒 Brakes 🢒 Air Antilock Brake System 🢒 Air Low Traction Indicator Inoperative

Circuit Description

The ignition 3 voltage circuit supplies 12 volts to the traction control switch. The electronic brake control module (EBCM) illuminates the Low Traction indicator by applying ground to the traction control active 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 for proper operation of the Low Traction indicator.

    2.

  2. This step tests for proper operation of the traction switch.

    3.

  3. This step tests for proper operation of the EBCM and the traction control active signal circuit.

Step

Action

Yes

No

Schematic Reference: Air Antilock Brake System Schematics

Connector End View Reference: Air Brake System Component Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition for 5 seconds.
  2. Turn ON the ignition while observing the Low Traction indicator.

Does the Low Traction indicator illuminate for 3 seconds and then turn OFF?

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the traction control switch harness connector.
  3. Connect test lamp between the traction control active signal circuit and a good ground.
  4. Turn ON the ignition.

Does the test lamp illuminate for 3 seconds and then turn OFF?

Go to Step 4

Go to Step 5

4

Inspect for poor connections at the traction control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 6

5

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

Did you complete the replacement?

Go to Step 9

--

6

Inspect for poor connections at the harness connector of the electronic brake control module (EBCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

  1. Turn OFF the ignition.
  2. Disconnect from the EBCM, the harness connector containing the traction control active signal circuit.
  3. Test the traction control active signal circuit for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find the correct condition?

Go to Step 7

Go to Step 8

8

Replace the EBCM. Refer to Control Module References for replacement, setup, and programming

Did you complete the replacement?

Go to Step 9

--

9
  1. Turn OFF the ignition for 5 seconds.
  2. Turn ON the ignition while observing the Low Traction indicator.

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

System OK

Go to Step 3