GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 STS 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 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 instrument panel module (IPM) monitors the brake pedal position sensor. When the brake pedal is applied, the IPM detects a predetermined voltage signal. The IPM 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 IPM.
    • 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

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. Verify that DTC P0571, P0572 or P0573 are not set as current.
    3. ⇒If any of these DTCs are set, refer to DTC P0572 or P0573.
  3. Verify that DTC P0703 is not set.
    4. ⇒If DTC P0703 is set as current, replace the IPM. 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 ECM or IPM replacement, setup and programming