Ford PL448 OBD-II Trouble Code Definition: PL448 Catalyst Bypass Flap Circuit PL448 Ford OBD-II Trouble CodeDescription: Ferrari OBD Trouble Code Pl448 Catalyst Bypass Flap Circuit Solutions Malfunction (sig/min/max) Check wiring Check the valve Check vacum leakage Check functionality in diagnosis mode Sorry no other information,Please help us to improve,Any information is appreciated.Thanks. […]