DTC P0703 - Brake Switch Malfunction: Condition

WARNING: This page is about a different car, the 1997 Mazda Millenia. However, it is still accessible from the selected car via links, so may be relevant.

DTC is set when ECM has not received brake switch signal while vehicle is operating. Possible causes are:

Brake switch malfunction.
Open or short circuit between brake switch terminal and terminal No. 1O on Engine Control Module (ECM).
Open or short in power supply circuit.