Due to design of body, field of view provided by outside rearview mirror is limited and there will always be blind spots. To constantly monitor adjacent lanes and area behind car, manufacturer has developed an electronic lane change assistance system that supports the driver when overtaking and changing lanes.
Lane change assist is also known as "departure assist", "lane change assist" and "side blind spot assist". Audi's electronic lane change assistance system is called "SWA".
Functional description of lane change assist system
The car's electronic lane change assist monitors rear and both sides of vehicle using ultrasonic sensors mounted on both sides of rear of vehicle. When vehicle speed exceeds 60 km/h, radius of curvature of road is at least 170 m (i.e. close to a straight line), and then main switch (E530) of lane change assist system is pressed, SWA system will be activated. If SWA detects that a moving object is approaching that could endanger vehicle when changing lanes and exiting, warning light on side rearview mirror will illuminate. times to alert driver. To set brightness of warning light, you can select corresponding brightness value in MMI.
How lane change assist system works
A key component of lane change assist system is image sensor, which has various technical contents. Early lane change assist systems used ultrasonic sensors, while more recent lane change assist systems use cameras.
An ultrasonic sensor uses electromagnetic waves to detect and locate targets. Its principle of operation is to first emit high-frequency electromagnetic beams (i.e. microwaves), and then receive and analyze microwaves reflected from obstacles. Different objects have different microwave reflection characteristics. Metal objects can reflect microwaves very well, while plastic objects hardly transmit microwaves. In this way, movement around vehicle can be detected by ultrasonic sensor.
Audi cars use two ultrasonic sensors and two control units. The control unit is integrated with ultrasonic sensors and installed in rear bumper. One of these two control units is master controller, which belongs to users of extended CAN bus, and other is slave controller.
Lane change assist system overhaul
A correct installation of control unit and ultrasonic sensor (including height and horizontal angle) is a prerequisite for correct operation of Audi SWA system, otherwise rear dynamics of vehicle may be incorrectly detected.
In event of a traffic accident, rear-end collision, replacement of bumpers and associated brackets, replacement of system components, it is necessary to calibrate Lane Change Assist system. Special equipment should be used for calibration, such as V.A.S6350 calibration panel, V.A.S6350/1 wheel centering (wheel centering receiver) and V.A.S6350/2 electronic rangefinder, etc. How to install calibration equipment.
If you use V.A.S505X for diagnosis, you can enter address code "3C" (Auxiliary Lane Change Control Unit) and V.A.S505X will be able to read fault codes, measure data blocks, and perform related matching operations in lane change assistance system . .
A common system failure is a malfunction of lane change assist system. In FAW-Volkswagen Audi A6L, instrument cluster displayed "lane change assistance not available". Connect a fault diagnosis tool, select address code "3C" and read static fault code "447" in lane change assist control unit - function limited due to overvoltage, "532" - supply voltage exceeds upper limit. Then check actual voltage of lane change assist control unit J769 and check that it is very different from value in data stream. Replaced Lane Change Assist control unit, problem fixed.
Also, don't blindly rely on lane change assist. Be vigilant when changing lanes, control your vehicle speed, be ready to brake at any moment, and check operation of ultrasonic sensor or camera frequently to avoid unnecessary accidents when changing lanes.