Inspection Procedure 5: Brake warning light does not illuminate when the ignition switch is turned to ON position (engine stopped): Operation

WARNING: This page is about a different car, the 2014 Mitsubishi Outlander. However, it is still accessible from the selected car via links, so may be relevant.

ASC-ECU sends the illumination request signal of the break warning light to the combination meter through ETACS-ECU via the CAN communication.
ASC-ECU illuminates brake warning light via ETACS-ECU for approximately 3 seconds for bulb check with the ignition switch turned to the ON position.