Ford P1804 OBD-II Trouble Code Definition: P1804 Ground Control Relay P1804 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P1804 Ground Control Relay Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. PSA OBD Trouble Code P1804 Transmission 4-wheel drive High indicator circuit failure Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. […]