Manoeuvering with a trailer can become a test of patience if you don't have much practice. This is because the trailer doesn't's always react as you may expect - among other things, the steering is reversed. The steering angle is decisive for precise reversing, and the optional Trailer Assist trailer maneuvering system will take care of steering for you. First select reverse gear, press the parking aid button and use the mirror adjustment switch to set the direction in which the trailer should be steered. Your car will now steer automatically while you just need to take care of changing gear, accelerating and braking. This means you stay in control at all times.