Mercury Grand Marquis P0403:EGR→ Circuit Malfunction
P0403 is a very common trouble code. It is a generic code, which means that it has the same meaning for the Mercury Grand Marquis as it would any other vehicle. It affects the EGR (Exhaust Gas Recirculation System and technically means: P0403: EGR→ Circuit Malfunction A circuit malfunction implies that there is a wiring … Read more