My friend's 05 XJ8L had front both badly suspensions and won't raise up, so he replaced them by brand new arnott air struts.
But the problem is front right one always lower a bit and non adjustable by SDD.
Therefore, he bought another new arnott strut for his front right, but it still non adjustable via sdd.
Strange thing is when I do the reprograming, the pump keep comes on and off, SDD shows level in progress, so I have to press abort to make it stop but not works.
There is no error codes but the front shocks always in the maxiam ride height even I losen the air tube manally.
We did swapped new air valve block, new front and rear air shocks, two used ASM from two same year model normal working XJ, few used front&rear height sensors but in normal working order, a refurbished air pump and the other two from normal working car.

Cant figure out is there something I missed?

 

I know it is too simple but sounds like the height sensor is physically disconnected.