adding to Knightarmor's guide.
I'm adding some more detailed info/pics.
This was one of the more painful cabin air filter replacement's I've done.
Why they put it in such an obscure place with no space to even open the door/flap completely is beyond me.
I come from japanese cars and they are literally one or two screws/clips from accessing the cabin filter.
This 2016 X1 is my first german car just learning their engineering design...
Here goes:
Tools you need:
1x 8mm socket/ratchet
1x T2 driver
You're gonna take off this rectangular cover with a 12v outlet held by an 8mm nut on each side.
Then it should easily fall out from the two tabs in the back
Remove all connectors and 12v harness clip.
Remove the T2 screw holding the side kick panel.
I removed the foot vent piping as well to get more space back there.
If you can wiggle your way without it... good luck.
This also requires removing the hidden T2 screw:
Then follow the piping up the back and pull it out from the connection.
No pic cuz it's impossible to get back up there. Just feel for it and it should pop out easily.
Open the cabin filter door clip
Remove the filters and take note of the air flow direction:
Once you pull the first one out, second one needs to be lift up and pulled out by the small flap on the filter.
Put new filters in the same air flow direction.
Mine look mangled because I had to shove it in the small door opening that BMW decided to cram in that space.
Put back panels/vents the backwards order you pulled them.
Total time spent: ~30min.