Air Suspension Calibration

[jdhx]

Folks, need help with the measurement process as I am not sure if I am doing it correctly.

1. WHEN do I take the measurement 
     a) When the car is parked and turned off or does it need to be running in Comfort mode or something else?
     b) Or, when I initiate the calibration the car does some leveling action. Do I need to take it right after this?

2. HOW do I take the measurement ACCURATELY?
    a) I tried with a metal measurement tape but I can imagine the numbers can be quite off if I am slightly off center and/or the not square from the ground. Hoping there's a better to way that is more accurate.
    b) Does the car need to be on flat even surface? My garage and driveway has a considerable slope and I am not sure if the car is leveling itself to compensate for it.

1. After the calibration process has started and it ask you what the measurements are.  That is because the process puts the suspension into a known state.

2. I do the measurements in two stages.  Before I start the calibration I measure the top of the disk in the centre of the wheel to ground (x) and the diameter of the disk (y).  Then when the calibration process asks for the values I measure the wheel arch to ground (z).  The value I input is z-x+y/2.  I do it this way because it is easier to measure from solid ground upwards than to measure wheel arch to centre of wheel.  Of course y does not vary and x only depends on temperature so will not vary much.  The car does not need to be on absolutely flat even ground but the more flat and even the better.

Well you did ask!