GM Service Manual Online
For 1990-2009 cars only

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 B2745 00: Traction Control Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

TCS switch signal circuit

B2745

1

--

--

Ground

--

1

--

--

1. Traction control cannot be manually disabled.

Circuit/System Description

The driver may disable the Traction Control System (TCS) by pressing the traction control switch. The body control module (BCM) supplies a 12-volt signal on the traction control signal circuit. When the traction control switch is pressed, this voltage signal is grounded.

Conditions for Running the DTC

Ignition ON.

Conditions for Setting the DTC

The BCM detects low voltage on the traction control signal circuit for 60 seconds.

Action Taken When the DTC Sets

    • The BCM sends a serial data message to the electronic brake control module (EBCM) informing the EBCM that the desired TCS state cannot be determined.
    • The EBCM defaults the TCS status to enabled.

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. Ignition ON, verify the scan tool BCM TCS Switch State parameter is Released.
  3. If not the specified value, test the signal circuit terminal I for a short to ground.
  4. Install a 3A fused jumper wire between the signal circuit terminal I and the ground circuit terminal H. Verify the scan tool BCM TCS Switch State parameter is Pressed.
  5. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance.
  6. If all circuits test normal, test or replace the traction control switch. If DTC resets replace the BCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Accessory Switch Replacement
    •  Control Module References for BCM replacement, setup, and programming.