DTC Descriptor
DTC P0703: Brake Switch Circuit 2
Diagnostic Fault Information
Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
Circuit/System Description
The body control module (BCM) monitors the brake pedal position (BPP) sensor. The BCM sends a GMLAN serial data message to the engine control module (ECM) indicating the status of the stop lamps.
Conditions for Running the DTC
The engine is ON.
Conditions for Setting the DTC
| • | The ECM 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 ECM stores the DTC information into memory when this diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | All of the scan tool cruise control function switch parameters are set to Off. |
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 the BCM has been replaced, the BPP sensor must be calibrated.
Reference Information
Schematic Reference
Cruise Control Schematics
Connector End View Reference
Computer/Integrating Systems Connector End Views
Electrical Information Reference
Circuit/System Testing
Important:
| • | Fix any Brake System related DTCs before using this diagnostic. |
| • | Perform the calibration procedure for the BPP sensor. |
Note: This DTC may be stored as a history DTC without affecting the operation of the BCM. Do not replace the BCM if this DTC is stored only as a history DTC and is not retrieved as a current DTC.
Using a scan tool, is DTC P0703 current in the ECM?
| ⇒ | If DTC P0703 is current in the ECM, replace the BCM. |
| ⇒ | If DTC P0703 is not current in the ECM, the system is OK. |
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
Control Module References
for BCM replacement, setup, and programming
