My 2016 bottomed out the other day with a mulfunction message regarding the airmatic suspension ( rear) . It is located between the rear bumper and the adblue tank. After removal of the plastic protective cover I noticed the two clear plastic air tubes been rubbing against the wires that send power to the unit, hence malfunction message, and both wires were chaffed and perished. After repairing the wires ,which is very tricky, the unit is working again. On putting everything back together, I covered the two pipes with protective insulation to stop any future problems. Hope this post help some body. I can post photos on request.