2016 Audi A3 / S3 — Owner's Manual
If you plan to tow a trailer, please remember that the additional load will affect durability, economy and performance. Trailer towing not only places more stress on the vehicle, it also calls for more concentration from the driver. For this reason, always follow the operating and driving instructions provided and use common sense. Use a weight-carrying hitch conforming to the gross trailer weight.
The hitch must be suitable for your vehicle and trailer and must be mounted securely on the vehicle's chassis at a technically sound location. Use only a trailer hitch with a removable ball mount. Always check with the trailer hitch manufacturer to make sure that you are using the correct hitch. Do not use a bumper hitch.
The hitch must be installed in such a way that it does not interfere with the impact -absorbing bumper system. No modifications should be made to the vehicle exhaust and brake systems. From time to time, check that all hitch mounting bolts remain securely fastened. When you are not towing a trailer, remove the trailer hitch ball mount.
This prevents the hitch from causing damage should your vehicle be struck from behind. If your trailer is equipped with a braking system, check to be sure that it conforms to all regulations. The trailer hydraulic brake system must not be directly connected to the vehicle's hydraulic brake system.