P0703

DTC P0703

Circuit Description

The body control module (BCM) sends brake signals via the GMLAN serial data circuit to the transmission control module (TCM) and to the engine control module (ECM) indicating the status of the stop lamps.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0703 Brake Switch Circuit 2

Conditions for Running the DTC

The engine is ON.

Conditions for Setting the DTC

* The TCM or the ECM detects a missing or invalid brake signal from the BCM.
* This diagnostic runs continuously.

Action Taken When the DTC Sets

* The malfunction indicator lamp (MIL) will not illuminate.
* The autograde braking is inhibited.
* The Cruise Control System is disabled.
* The TCM and the ECM stores the DTC information into memory when the diagnostic runs and fails.
* The TCM and the ECM records the operating conditions at the time the diagnostic fails. The TCM and the ECM stores this information in the Failure Records.

Conditions for Clearing the DTC

* The DTC becomes history when the fault is no longer present.
* A History DTC clears after 100 malfunction free ignition cycles.
* Use the scan tool in order to clear the DTC.

Diagnostic Aids

* If a BCM has been replaced, the 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 BCM. If stored only as a history DTC and not retrieved as a current DTC, do not replace the BCM.
* If this DTC is retrieved as both a current and a history DTC, replace the BCM.
* For an intermittent condition, Refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 6:

The numbers below refer to the step numbers located in the diagnostic table.
2. This step is performed in order to confirm that DTC P0703 is current within the TCM or the ECM.
3. This step is performed in order to correct a BPP sensor that must be calibrated, possibly due to a BCM replacement or for a BPP sensor that is out of adjustment.