air suspension inactive

Hi

I'm new to this site 

I have yet another issue with my air suspension, 

took my 2005 x5 4.8is to bmw and I was told the compressor was faulty ( the suspension calling for air but compressor not turning on). 

no fault codes for sensors or modules just a few strange codes - drain on compressor ? 

Removed the compressor checked the piston ring and solenoids all o.k.

wired the compressor direct to the battery, it ran fine with no air leaks and good pressure 

checked fuses all o.k disconnected the battery to see if this would remove the sus inactive warning... no luck

had the sus reset at Bmw and the compressor worked fine pumping the suspension to the max height and then returning to normal when I drove away,

next day sus inactive back on ( the suspension has not dropped )

has anyone come across this or anything close to this fault

thanks