P0703

DTC P0703

Diagnostic Instructions

* Perform theDiagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* ReviewStrategy 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
- Brake Switch Circuit




Circuit/System Description

The body control module (BCM) monitors the stop lamp switch, mounted on the brake pedal. The BCM sends a serial data message to the engine control module (ECM) indicating the status of the stop lamp switch.


Conditions for Running the DTC

* The ignition is ON.
* The cruise switch 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 (Electrical Diagrams)
* Exterior Lights Schematics (Exterior Lights Schematics)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cruise Control Description and Operation (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

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

• If the brake system or brake lights do not operate properly, refer toDTC 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.




Repair Instructions

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


Control Module References (Programming and Relearning) for BCM or ECM replacement, setup, and programming