I have a different part number on my etk however it begins the same. It may have been superseded. The sensors are around $100 each so I would say it is the module. It is located in the rear boot under neath the spare wheel you will see a black round compressor.Upon that is a connection of some sort the end of that is a square control unit which is the module. At least thats how it looks on this pic. This part is fitted to e39 5 series as well so may be able to get one from the breakers. The suspension does have a relay so always check that. Looks like an easy fit maybe just a plug out plug in part. If you have a friend with an x borrow their unit to confirm diagnosis. I never trust the dealers. Hope this helps