Audi A4   Controls   Audi side assist  Lane change assist feature
Applies to vehicles: with Audi side assist
The side assist is active above a speed of about 30 km/h.
-A- Vehicles approaching from behind
In certain cases, a vehicle is judged to be critical in the event of a lane change even if it is still some distance away. The faster a vehicle approaches, the earlier the warning will appear on the exterior mirror.
-B- Vehicles moving at a similar speed
The warning lamp in the relevant exterior mirror will warn you of vehicles that are moving with the flow of traffic at about the same speed as you if they are judged to be critical in the event of a lane change. In all cases, the side assist will give a warning for the vehicles it has detected at the latest when they enter the "blind spot".
-C- Other vehicles being overtaken
When you are overtaking another vehicle slowly, with a speed differential of less than 15 km/h, the warning lamp in the exterior mirror will light up as soon as the other vehicle enters your blind spot.
If you are overtaking another vehicle quickly, with a speed differential of more than 15 km/h, the warning lamp will not light up.
System limitations
The radar sensors are designed for normal lane widths and monitor the lanes immediately to the left and right of your vehicle. In certain situations the warning lamp on one of the exterior mirrors may light up even if no vehicle is travelling in an area that could be critical in the event of a lane change. For example:
  • When you are travelling in a narrow lane or when you are not travelling in the centre of the lane. In this case the system may monitor another lane and register a vehicle that is not in fact travelling in an adjacent lane.
  • When you are driving into a bend. The side assist may react to a vehicle two lanes away.
  • If the system detects other objects (such as crash barriers, etc).
  • In poor weather conditions. The functionality of the side assist is then restricted.
The radar sensors Fig. 2 must not be obstructed by stickers, bicycle racks, deposits or any other substances which could impair the function of the system. For notes on cleaning, please refer to Link. The side assist must not be used when towing a trailer.
WARNING!
  • Always watch the road and the area surrounding the vehicle. The side assist feature is not a substitute for the full concentration of the driver. The driver is always responsible for the safety of lane changes and other manoeuvres.
  • In certain situations, the system may not function properly, or the functionality of the system may be restricted. For example:
    • If other vehicles are approaching very quickly, or if you are overtaking other vehicles quickly. The warning lamp may not light up in time.
    • In poor weather conditions, such as heavy rain, snow or road spray.
    • If you are travelling in very wide lanes, in tight bends or over crests. The system may not detect vehicles in the adjacent lane because they are outside the area covered by the sensors.
Caution!
Impacts or damage to the bumper, wheel arches or underbody can cause misalignment of the sensors. This can impair the functionality of the system. Have the systems checked by a qualified workshop.
Note
The warning lamps on the exterior mirrors may not be properly visible if tinted foil is affixed to the side windows on the driver's or passenger's side.

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