P0703

DTC P0703

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC P0703 00
- 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 ECM/PCM stores the DTC information into memory when this diagnostic runs and fails.
* 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 last test failed, or the current DTC, clears when the diagnostic runs and does not fail.
* A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic.
* A clear code command is received from a scan tool.



Reference Information
Schematic Reference

Cruise Control Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

* Cruise Control Description and Operation (Description and Operation)
* Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)

Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

Important:
* If a BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration (Programming and Relearning).

* 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.




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.

• If either DTC is set as current, refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).

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 as current, replace the ECM/PCM.




Repair Instructions

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

* Brake Pedal Position Sensor Replacement (Brake Pedal Position Sensor Replacement)
* Control Module References (Programming and Relearning) for BCM, ECM, or PCM replacement, setup and programming