Ford P1820 OBD-II Trouble Code Definition: P1820 Internal Mode Switch Circuit A Low P1820 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P1820 Internal Mode Switch Circuit A Low Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. PSA OBD Trouble Code P1820 Transmission transfer case clockwise shift relay coil circuit failure Sorry no other […]