Inspection Procedure 4: MULTIMODE Keyless Entry System Function Does Not Work At All. <Vehicles With Electric Retractable Remote Controlled Door Mirrors>: Notes
WARNING: This page is about a different car, the 2019 Mitsubishi Eclipse Cross. However, it is still accessible from the selected car via links, so may be relevant.
CAUTION:
Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.