DTC U1533: Invalid Data Received From Rear/Side Radar Control Module
WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.
DTC detecting condition:
Error data is received from radar sensor.
NOTE:
Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE