GM Service Manual Online
For 1990-2009 cars only

DTC Descriptor

DTC B2745: Traction Control Switch Circuit

Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

TCS switch signal circuit

B2745

12

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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

The ignition is 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 DTC clears automatically from Current status when the fault is corrected. Use a scan tool to clear the DTC from history status.

Diagnostic Aids

An intermittent short to ground on the traction control signal circuit is the most likely cause of a history DTC when no problem is found. When the Conditions for Setting this DTC are present, the driver is not able to disable traction control.

Reference Information

Schematic Reference

Antilock Brake System Schematics

Connector End View Reference

    •  SIR Connector End Views
    •  Computer/Integrating Systems Connector End Views

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

Traction control can be disabled/enabled when the traction control switch is pressed and released.

Circuit/System Testing

  1. Turn OFF the ignition for 5 seconds, then turn ON the ignition and wait at least 60 seconds.
  2. If DTC B2745 does not reset, go to Diagnostic Aids
  3. Turn the ignition OFF. Disconnect the traction control switch harness connector. Turn the ignition ON and wait at least 60 seconds.
  4. If DTC B2745 does not reset, replace the traction control switch.
    If the DTC B2745 resets, check the TCS switch signal circuit for a short to ground or replace the BCM.

Repair Instructions

Important: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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