GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2008 🢒 Terraza 🢒 DTC 🢒 DTC P0703

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 P0703: Brake Switch Circuit 2

Circuit/System Description

The body control module (BCM) monitors the brake pedal position sensor. When the brake pedal is applied, the BCM detects a predetermined voltage signal. The BCM sends a serial data message to the engine control module (ECM) indicating the status of the stop lamps.

Conditions for Running the DTC

The engine is ON.

Conditions for Setting the DTC
    • The ECM receives an invalid brake pedal status serial data message from the BCM.
    • This diagnostic runs continuously.

Actions Taken When the DTC Sets
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The cruise control system is disabled.

Conditions for Clearing the DTC
    • The condition responsible for setting the DTC no longer exists.
    • A history DTC will clear after 40 malfunction-free ignition cycles have occurred.

Reference Information

Schematic Reference

Cruise Control Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Cruise Control Description and Operation
    •  Exterior Lighting Systems 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 Verification
  1. Repair any brake system related DTCs before performing this diagnostic.
  2. Road test the vehicle. Verify that DTC P0572 or P0573 are not set as current.
    3. ⇒If either DTC is set as current, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  3. Verify that DTC P0703 is not set.
    4. ⇒If DTC P0703 is set as current, replace the BCM. Clear the DTC and road test the vehicle. If DTC P0703 resets as current, replace the ECM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Brake Pedal Position Sensor Replacement
    •  Control Module References for BCM or ECM replacement, setup and programming