Cruise control system diagnostic trouble codes
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.
The ACC system consists of the ACC/FCM-ECU, engine control module (ECM), ASC-ECU, transaxle control module (TCM), ETACS-ECU, control switches and sensors. If the ACC/FCM-ECU detects a malfunction on any of those components, the ACC/FCM-ECU estimates where the problem may be occurring, and will set a diagnostic trouble code.