Ford P3491 OBD-II Trouble Code Definition: P3491 Cylinder 12 Deactivation/lntake Valve Control Circuit Low P3491 Ford OBD-II Trouble CodeDescription: OBD Trouble Code P3491 Cylinder 12 Deactivation/lntake Valve Control Circuit Low Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. […]