To realign the sensor takes a specialist piece of equipment. i did hit something, fox and one of the plastic holders broke and knocked the sensor off the skew. was quoted approx £400 to set up same. Bought a mounting kit and replaced the plastic clip pushed the sensor back in and cleared fault with vagcom. no more problems. It has been reported that it may be a software glitch! http://www.pro-align.co.uk/proalignproducts/vw-group/vw-alignment/ specialist tool. they reckon very expensive!