For 1990-2009 cars

### 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.

### DTC Descriptor

DTC B0827: Traction Control Switch Off Indicator Circuit Low

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
TCS Requested Indicator Control | B0827 | B0828 | B0828 | --
Ground | -- | B0828 | -- | --

### Circuit/System Description

After the traction control switch (TCS) is pressed and released, the LED on the switch illuminates. The body control module (BCM) illuminates the LED by supplying adequate current to the high side of the LED.

### Conditions for Running the DTC

• | Ignition ON.

• | Ignition voltage is greater than 10 volts.

### Conditions for Setting the DTC

The BCM detects low voltage on the traction control requested indicator control circuit when the LED is switched ON.

### Action Taken When the DTC Sets

• | The EBCM disables the Antilock Brake System (ABS)/Traction Control System (TCS)/Vehicle Stability Enhancement System (VSES) for the duration of the ignition cycle.

• | A DIC message and/or a warning indicator may be displayed.

### Conditions for Clearing the DTC

• | The condition for setting the DTC is no longer present.

• | The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.

### Reference Information

#### Schematic Reference

Antilock Brake System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

ABS Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the traction control switch.
2. Test for less than 5 ohms between the ground circuit terminal H and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify the scan tool BCM TCS Switch State parameter is Released.

⇒ | If not the specified value, test the signal circuit terminal J for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal J and the ground circuit terminal H. Verify the scan tool BCM TCS Switch State parameter is Pressed.

⇒ | 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.

5. Ignition ON, verify the scan tool BCM Traction Switch LED parameter is OFF.

⇒ | If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the BCM.

6. Install a 3A fused jumper wire between the signal circuit terminal B and the ground circuit terminal H. Verify the scan tool BCM Traction Switch LED parameter is ON.

⇒ | 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.

7. If all circuits test normal, test or replace the traction control switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Accessory Switch Replacement

• | Control Module References for BCM replacement, setup, and programming.