Ford P0231 OBD-II Trouble Code Definition: P0231 Fuel Pump Secondary Circuit Low P0231 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P0231 Fuel Pump Secondary Circuit Low What does the code mean? OBD-ii Code P0231 definition: The fuel pump is powered by the fuel pump relay. When the PCM (powertrain control module) activates the fuel pump relay, […]