Quite likelySoft fault.
Next step check for corrosion in the sensor connectors. You could also look at sensor readings in the "Heights" tab forcing up and down movement on the suspect corner and look for erratic readingsWell I can cross 1 of the list as in the connections in the footwell, as they are all good as you told me to check them before I got the ESA suite from you and I keep checking them, airsprings have been checked with a spray and soapy water and I could not find anything. The compressor only runs if I change the suspension or when it changes after a motorway run.
It can, yes, if there are bare patches on the sensors at the current standard height settings, then calibrating it and/ or knocking the corner settings collectively up or down a few steps can put the car at a level where all four sensors are at good points of their tracks. I don't say that is the ONLY option, I'm just suggesting a quick win, before the OP starts doing the funky stuff. Personally I would always calibrate a faulty system before then ripping it apart, EAS or whatever, eliminate the easy things first.So you think that calibration blocks will overcome what is obviously a fault? The car levels up when driven or sometimes kicks up to full height, tell me how recalibrating will cure that?
There are many possibilities, a contaminated sensor giving erratic reading, calibration will not help that. A corroded sensor connector causing erratic readings,calibration will not help that. A split that opens and closes in an airspring, calibration will not help that. Corrosion in the white connectors at the foot of the a post in the passenger footwell, quite a common problem, calibration will not help that. I could list many other possibilities that have obviously never crossed your mind.
You prefer to bodge a problem rather than fix it. I think you have a lot to learn about the EAS.It can, yes, if there are bare patches on the sensors at the current standard height settings, then calibrating it and/ or knocking the corner settings collectively up or down a few steps can put the car at a level where all four sensors are at good points of their tracks. I don't say that is the ONLY option, I'm just suggesting a quick win, before the OP starts doing the funky stuff. Personally I would always calibrate a faulty system before then ripping it apart, EAS or whatever, eliminate the easy things first.