Ive calibrated the height on my 05 XJR numerous times (I've lowered a few mm from factory height) but I never seem to get it to actually lower to the values i enter.
I also notice when i park my car sometimes the heights of the front and rear are way off from what they should be. itll be higher on one side of the car, or maybe just front, or maybe rear.

Has anyone else experienced this inconsistent behavior from the Air suspension?

I don't get error codes, and my struts are new in the front. Air compressor is good.

 

I believe the specs on this air suspension indicate that the system will keep the trim heights within approx. 1/2 inch of calibration. That's a pretty large variance, and I can confirm I do see occasional differences if I'm looking for them. Typically I find in the winter the system doesn't raise the car overall as high as in summer, but still well within tolerance of correct ride height.

If I've parked on a hill or curb, sometimes it needs a cycle to get back to normal. But if you're seeing a large variation from left to right or front to rear, then you might have a bad height sensor at one wheel. One member posted about a chafing wire in the front-left wheel arch (to the height sensor) that was giving him issues.

 

To be clear, if you want it to go lower than the standard heights then when you measure the current heights you have to add the amount you want to lower the car to those measured heights before you enter them into the SDD. You have to fool it into thinking it's higher than it actually is.

Is that what you did ?

Edit: A second thought has just occurred.
Are you putting in the vertical height of the wheel centre below the underside of the wheel arch, or the slant height, ie the straight line distance from the underside of the top of the wheel arch to the centre of the wheel insert ?
The correct measurement is the former; the latter is about a centimetre greater, and hence will make the car sit about a centimetre lower than spec.

 

Yeah Ive been adding the heights i wanted. It just seems super inconsistent with how it lowers the car. Ive been measuring vertically on each arch as well.

Would a dying battery cause a strange issue like this? I recently had the 'cruise not available' during a 3 hour car trip, and I know a dying battery makes the car act strange. My car cranks fine, but Ive read numerous stories about folks having strange issues with their cars with a dying battery