Some 2020-2021 Corsair/Nautilus/Navigator/Aviator, 2021 Mustang Mach-E vehicles equipped with Phone-as-a-Key may exhibit Phone-as-a-Key concerns and have diagnostic trouble code(s) (DTC) U200D:15, U200E:15, U200F:15, B15**:31, B15**:49 and/or B15A5:56 stored in the remote function actuator (RFA) module. If the vehicle is exhibiting other symptoms outside of Phone-as-a-key concerns, address those first. If any of these DTCs are detected during diagnostics, clear the DTCs, reflash RFA to the latest software level and start a new Ford Diagnosis and Repair System (FDRS) session. Verify that DTCs are no longer present. If only the B15**:31, B15**:57 and/or B15A5:56 DTC(s) returns in the RFA after a self test, follow normal Workshop Manual (WSM) diagnostics, Section 419-01C.
