The ignition 3 voltage circuit supplies a momentary application of ground to the traction control switch. The electronic brake control module (EBCM) illuminates the Traction Off indicator by applying voltage to the service traction control signal circuit.
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to the following:
For all traction control DTC resets, verify EC30 ECU configuration by turning the ignition ON and monitoring the ECU LEDs.
The numbers below refer to the step numbers on the diagnostic table.
This step tests for proper operation of the Traction Off indicator.
This step tests for stuck open contacts in the traction switch.
This step tests for stuck closed contacts in the traction switch.
This step tests for an open or short to ground in the service traction control signal circuit.
This step tests for an open or short to ground in the traction control switch 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 | |
Does the Traction Off indicator illuminate for 3 seconds and then turn OFF? | Go to Step 4 | Go to Step 3 | |
3 |
Does the test lamp illuminate for 3 seconds and then turn OFF ? | Go to Step 7 | Go to Step 9 |
4 | Press and release the traction control switch. Does the Traction Off indicator turn ON ? | Go to Diagnostic Aids | Go to Step 5 |
Important: Do not disconnect the traction control switch harness connector during this step.
Does the Traction Off indicator turn ON and OFF? | Go to Step 7 | Go to Step 6 | |
Does the test lamp turn ON ? | Go to Step 7 | Go to Step 9 | |
7 | 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 11 | Go to Step 8 |
8 | Replace the traction control switch. Refer to Air ABS Traction Control Switch Replacement . Did you complete the replacement? | Go to Step 12 | -- |
Did you find the correct condition? | Go to Step 12 | Go to Step 10 | |
With the EBCM harness still disconnected, test the traction control switch signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find the correct condition? | Go to Step 12 | Go to Step 11 | |
11 | Replace the EBCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | -- |
12 |
Does the Low Traction indicator illuminate for 3 seconds and then turn OFF? | System OK | Go to Step 3 |