DTC B278B: Can Control Module Stuck
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:
When incompatible state is detected two times in a row in every Wake-up of microcomputer, after detecting incompatible state between written data and read-out data to/from register for CAN check after resetting.
(When the data do not match for three consecutive times (one time at resetting + two times at microcomputer Wake-up).)
Trouble symptom:
The operation is performed with information of the last value as right, but basically the system operation is deactivated.
NOTE:
Perform the diagnosis for LAN system. Ref. to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE