TSB 19-2201

Some 2018-2019 Mustang vehicles equipped with a 5.0L engine may exhibit an illuminated malfunction indicator lamp (MIL) with diagnostic trouble code (DTC) P0420 and/or P0430. This may be due to the operation of the PCM. To correct the condition, follow the Service Procedure steps to replace the affected catalytic converter and reprogram the powertrain control module (PCM).