Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
EBCM Ground Circuit | 1 | -- | -- | -- |
1. VSES and TCS inoperative | ||||
Circuit Description
The stability system disable indicator is controlled by the instrument cluster via class 2 serial data messages from the electronic brake control module (EBCM). When the instrument cluster sees a class 2 message from the EBCM that tells the instrument panel cluster (IPC) that the stability system is malfunctioning, the EBCM then disables vehicle stability enhancement system (VSES) and traction control system (TCS) and sends a message to the instrument cluster to turn the stability system disable indicator always on and TCS indicators ON. Each time the ignition is cycled from OFF to ON, the VSES is enabled:
The following conditions will cause the VSES/TCS indicators to illuminate:
| • | The EBCM has disabled the VSES/TCS due to a DTC. |
| • | The instrument cluster bulb check--When the ignition switch is turned to ON, the VSES/TCS indicators will turn ON for approximately 3 seconds and then turn OFF. |
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, command the scan tool IPC display test ON and OFF. The StabiliTrak indicator should turn ON and OFF.
- Observe the scan tool BCM Traction Control Switch parameter while pressing and releasing the traction control switch. The reading should change between Released and Pressed.
| ⇒ | If the indicator does not turn ON and OFF, replace the IPC. |
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the traction control switch.
- Test for less than 1 ohm between the ground circuit terminal A and ground.
- Ignition ON, verify the scan tool Traction Control Switch parameter is Pressed.
- Install a 3A fused jumper wire between the signal circuit terminal C and the ground circuit terminal 3. Verify the scan tool Traction Control Switch parameter is Released.
- If all circuits test normal, test or replace the traction control switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If not the specified value, test the signal circuit terminal C for a short to ground. If the circuit tests normal, replace the BCM. |
| ⇒ | If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
Component Testing
- Ignition OFF, disconnect the harness connector at the traction control switch.
- Test for infinite resistance between the signal terminal A and the ground terminal C with the switch in the open position.
- Test for less than 3 ohms between the signal terminal A and the ground terminal C with the switch in the closed position.
| ⇒ | If not the specified value, replace the traction control switch. |
| ⇒ | If greater than the specified range, replace the traction control switch. |
Repair Instructions
| • | Control Module References for BCM or IPC replacement, setup, and programming |
Repair Verification
Ignition OFF for 5 seconds, Ignition ON, observe that the ABS, TCS, and Low Traction indicators function by illuminating for 3 seconds then turns OFF. This is the bulb self test that operates upon every ignition key start cycle.
