Circuit Description
The Body Control Module (BCM) receives the input from the Traction Control Switch. The BCM then sends a class 2 message to the EBTCM telling the EBTCM the state of the switch. The BCM supplies voltage to the TCS switch and when the TCS switch is depressed the BCM sees the voltage go low and sends the EBTCM the message that the TCS switch state has changed. When the EBTCM receives the message from the BCM that the switch state has changed it turns on or off Traction Control and its TRAC OFF indicator depending on its previous state.
Diagnostic Aids
| • | It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. |
| • | Thoroughly inspect any circuitry that may be causing the complaint for the following conditions: |
| - | Backed out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal-to-wiring connections |
| - | Physical damage to the wiring harness |
| • | The following conditions may cause an intermittent malfunction: |
| - | A poor connection |
| - | Rubbed-through wire insulation |
| - | A broken wire inside the insulation |
| • | If an intermittent malfunction exists refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. |
Test Description
The numbers below refer to step numbers on the diagnostic table.
-
Checks if the Body Control Module is receiving a Traction Control Switch input.
-
Checks if the EBTCM is receiving a Traction Control Switch message from the Body Control Module.
-
Checks if the Body Control Module or the Traction Control Switch is at fault.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
DEFINITION: The TRAC OFF indicator does not come on when the Traction Control Switch is pressed to disable the Traction Control System. | ||||
1 | Was the Diagnostic System Check performed? | -- | ||
Does the TCS Switch state change properly as the switch is pressed and released? | -- | |||
Using a scan tool in ABS/TCS read the TCS Switch Status as you press and release the TCS Switch. Does the TCS Switch state change properly as the switch is pressed and released? | -- | |||
4 | Replace the EBCM/EBTCM. Refer to Electronic Brake Control Module/Electronic Brake and Track Control Module Replacement . Is the replacement complete? | -- | -- | |
5 |
Will the scan tool command the TRAC OFF indicator ON then OFF? | -- | ||
6 | Suspect the Instrument Panel Cluster. Refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console. Is the Replacement complete? | -- | -- | |
Does the TCS Switch status read when pressed with the jumper wire connected? | -- | |||
8 | Replace the Traction Control Switch. Refer to Traction Control Switch Replacement . Is the replacement complete? | -- | -- | |
9 |
Is the resistance within the range specified in the value(s) column? | 0-2 ohms | ||
10 | Repair CKT 1550 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
11 |
Is the resistance within the range specified in the value(s) column? | 0-2 ohms | ||
12 | Repair CKT 1571 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |
13 | Suspect the Body Control Module. Refer to Diagnostic System Check - Body Control System in Body Control System. Is the replacement complete? | -- | -- | |
