P0703

DTC P0703

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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)/powertrain control module (PCM) indicating the status of the stop lamps.

Conditions for Running the DTC

The engine is ON.

Conditions for Setting the DTC

* The ECM/PCM receives an invalid brake pedal status serial data message from the BCM.
* This diagnostic runs continuously.

Action Taken When the DTC Sets

* The cruise control system is disabled.
* The malfunction indicator lamp (MIL) will not illuminate.
* The ECM/PCM records the operating conditions at the time the diagnostic fails. The ECM/PCM stores this information in the Failure Records.

Conditions for Clearing the DTC

* A current DTC clears when the conditions for setting the DTC are no longer present.
* A history DTC clears after 40 consecutive malfunction-free ignition cycles.

Diagnostic Aids

* If a BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration.
* This DTC may be stored as a history DTC without affecting the operation of the ECM/PCM. If stored only as a history DTC, do not replace the BCM or ECM/PCM.

Circuit/System Verification

1. Repair any brake system related DTCs before performing this diagnostic.
2. Verify that DTC P0572 or P0573 is not set as current.

• If either DTC is set, refer to DTC P0572 or P0573. P0572

3. Verify that DTC P0703 is not set.

• If DTC P0703 is set as current, replace the BCM. Clear the DTC and road test the vehicle. If DTC P0703 resets, replace the ECM/PCM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests