Ford P1871 OBD-II Trouble Code Definition: P1871 Undefined Gear Ratio P1871 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P1871 Undefined Gear Ratio Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. PSA OBD Trouble Code P1871 Transmission mechanical transfer case 4×4 switch circuit Short to battery Sorry no other information,Please help us to improve,Any […]