P0703

DTC P0703

CIRCUIT 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 GMLAN serial data message to the powertrain control module (PCM) 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 PCM receives an invalid brake pedal status GMLAN serial data message from the BCM.
- This diagnostic runs continuously.

ACTION TAKEN WHEN THE DTC SETS
- The Cruise Control System is disabled.
- The PCM stores the DTC information into memory when the diagnostic runs and fails.
- The malfunction indicator lamp (MIL) will not illuminate.
- The PCM records the operating conditions at the time the diagnostic fails. The 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.
- Use the scan tool in order to clear the DTC.

DIAGNOSTIC AIDS
- If a BCM has been replaced, the brake pedal position (BPP) sensor must be calibrated. Refer to Brake Pedal Position Sensor Calibration in Lighting System.
- Repair any Brake System related DTCs before performing this diagnostic table.
- 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 PCM.
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.