Ford P0477 OBD-II Trouble Code Definition: P0477 Exhaust Pressure Control Valve Low P0477 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P0477 Exhaust Pressure Control Valve Low What does the code mean? OBD-ii Code P0477 definition: Exhaust Back Pressure Regulator – Is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase […]