Good product item worked out well but was not the issue or fault

Perfect for BMW X5 2018

This solved my problem for 2016 F15 35d. My problem started around 55k where left side rear air suspension would sag when parked. I first self replaced both air bags using OEM parts. This resolved the sagging problem for about two weeks until all of a sudden while on a short trip from home my car completely deflated and check engine light with a warning message "Chassis function restricted" came on.At that point I uninstalled the compressor unit for inspection. Sure enough the balls inside the dehumidifier chamber were wet. I dried the desiccant balls (I didn't replace them), cleaned the chamber and inspected the solenoid using a 12v - it was completely stuck which I'm sure occurred due to moisture. NOTE: Solenoid OEM part 442 051 021 1 is not sold anywhere (except few on ebay but 50 usd for just shipping), dealer intentionally wants you to replace the whole unit which was quoted for $1600 plust tax. After some searching for just the solenoid part I found a this part on Amazon and it seems to be compatible. After swapping this into the compressor unit and putting everything back together the problem went away. Car was able to raise the suspension at the correct hight. One thing to note: the check engine light with a warning message "Chassis function restricted" stayed on for 4 short driving trips and eventually turned off on its own. This saved me $

F15 X5 air suspension was dumping air on startup and bottoming out. I suspected it was this relief valve due to the symptoms. Upon disassembly the entire compressor assembly looked fine. Bench tested the solenoid and it would not engage. This unit worked as a direct replacement for the Wabco part which is not available separately. I will update if longevity appears to be an issue.

My 2016 BMW X5 (f15) 40e showed sagged rear air bag suspension on both sides so I started doing some online research and found out that a common fail point for the air compressor on many European cars is this solenoid valve. Moisture will enter the compressor at some point and start to rust out the solenoid valve rendering it useless even though you can hear it turn on. The BMW dealer will charge 2k to replace this compressor, and usually will charge 4k to replace the compressor and both air bags. Im not a mechanic and I dont like working on cars, but I was not about to pay 4k for something that could be fixed with $30 part.Thank goodness for all the youtubers out there who post videos about replacing/diagnosing the air compressor- they are the hereos for guys like me. Anyways if your compressor in not pumping out as much pressure as it should be, look into taking off the air compressor, taking it apart and looking at the air compressor for corrosion- if so, give this a shot. I posted pics of the air compressor corrosion, you cant really take apart the solenoid to inspect for corrosion but if there is any inside the compressor, you can be sure to have corrosion in the solenoid valve.After I replaced my solenoid valve on my air compressor and it filled the rear bags with air, I got under the vehicle and sprayed soapy water around the air bags to check for leaks and suprisingly did not find any. I thought the air leaks were a mandatory origin point for many of these compressor fails but it turns out that moisture getting into the compressor is just gonna happen with or without the leak in air suspension. So it turns out that I could have paid $4 thousand dollars at my BMW dealer for something that cost me only $30.The reason for that is because BMW dealer along with many other European Car Repair shops will automatically assume the airbags are leaking because it is a "wear & tear" item that lasts 4-5 yrs and needs to be replaced, so that costs approx 2k to replace, then the compressor will not fill bags adequately so they will order the entire air compressor assy which will cost another 2k. I called 2 other repair shops and they told me over the phone that I should be prepared to replace the compressor and air bags without even looking at my vehicle.This solenoid valve does not have any printed identification stamped on it, but it fits directly on the BMW OEM Compressor. I posted a pic of the BMW OEM solenoid valve and OEM Air Compressor. Good luck.