Supersedes Technical Service Bulletin Group 96 number 13-74 dated September 11, 2013. Customer complains that Audi Lane Change Assistant deactivates or is sporadically inoperative. Message ?Side Assist Unavailable? is displayed in the Driver Information Display when the system deactivates. Workshop finds that Audi Lane Change Assistant can be activated without issue. DTCs are stored in the Lane Change Assistance control module. A software issue within J769 causes a diagnostic fault, which deactivates the Audi Lane Change Assistant temporarily.