Circuit Description
The Traction Off indicator is controlled by the instrument cluster via serial data messages from the EBCM. When the body control module sees the traction control switch input grounded through the momentary traction control switch, it sends a serial data message to the EBCM that tells the EBCM that the traction control switch has been pressed. The EBCM then disables traction control and sends a serial data message to the instrument cluster to turn the Traction Off indicator ON. Each time the ignition is cycled from OFF to ON, the traction control system is enabled.
The following conditions will cause the Traction Off indicator to illuminate:
| • | The EBCM has disabled the TCS due to a DTC. |
| • | The driver manually disabling the TCS via the traction control switch. |
| • | The instrument cluster bulb check. When the ignition switch is turned to ON, the Traction Off indicator will turn on for approximately 3 seconds and then turn OFF. |
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2747 Traction Control Circuit Switch Low
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
The BCM detects a ground on the traction control switch signal circuit for longer than 60 seconds.
Action Taken When the DTC Sets
| • | The ABS remains functional. |
| • | The ABS indicator remains OFF. |
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and you used the scan tool Clear DTC function. |
| • | The BCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive ignition cycles. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Tests for the normal state of the TCS switch using a scan tool.
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Tests if the BCM is able to detect a change in TCS switch state.
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Tests for a stuck or shorted TCS switch. If the TCS switch is stuck or shorted, the state will change from On to Off when the TCS switch is disconnected.
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Tests for a short to ground in the TCS switch signal circuit.
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When the BCM is replaced, use a scan tool to perform the setup procedure for the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Antilock Brake System Schematics Connector End View Reference: Antilock Brake System Connector End Views or Computer/Integrating Systems Connector End Views in Vehicle Control System | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
Does the scan tool display Off? | Go to Step 3 | Go to Step 4 | |
Does the TCS Switch parameter change state? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
Does the scan tool display Off? | Go to Step 7 | Go to Step 5 | |
Test the signal circuit of the TCS switch for a short to ground. 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 body control module (BCM). 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 8 |
7 | Inspect for poor connections at the harness connector of the TCS 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 9 |
Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the repair? | Go to Step 10 | -- | |
9 | Replace the traction control switch. Refer to Electronic Traction Control Switch Replacement . Did you complete the repair? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
