Audi Lane Change Assistant deactivates or is sporadically inoperative when the vehicle is driven in slow-moving stop-and-go traffic, especially on roads with multiple lanes. The message "Audi side assist unavailable: Sensors blocked" appears in the driver information system. The system is able to be activated approximately ten minutes after the traffic condition is removed, or after an ignition cycle. Audi Lane Change Assistant can be activated without issue. No obstructions can be found. DTCs are stored in the Lane Change Assistance control module. The control module mounting brackets are securely fastened to the lower rear bumper, and no damage is found to the rear bumper area, on the inside or outside. (If any damage is found, it is not covered under warranty.) The control module mounting brackets are not broken or loose. If a loose bracket is found, repair as necessary using the Elsa Repair Manual. Submit a separate warranty claim, as this TSB does not cover this repair. The software of the Lane Change Assistance control module can deactivate the Audi Side Assist system in certain normal driving conditions because the nature of these driving conditions make it difficult for the Audi Side Assist system to track vehicles.