Hi,
Overall, very happy with my 2016 F26 X4 35d with 45,600Kms.
Was just about to order a new BMW OEM Part # 64116826346 for about US$100 shipped to Australia and chance it would fix the BMW XAUC SENSOR error in ISTA+ but decided to try something.
I removed the XAUC Sensor and got some 240 grit wet/dry sandpaper, used dry and folded a piece so it was about 1/4" wide and 2" long and moved it around so I could sand each of the 3 pins, re-attached and no more ISTA+ c90d60 error bmw from JBBE ECU.
Just to give the 3 pins some protection against corrosion, I sprayed just a little WD40 Water Resistant Silicone Lubricant spray on the 3 pins and plug, the silicone spray can says it protects metal from corrosin.
Cheerz