Thanks for the reply,
Since I installed the new compressor and distribution piece the codes are now gone. I think the problem was that my used compressor and rebuilt compressor was too weak to satisfy the filling request of the reservoir. So now the new compressor fills the unit in 1 min to about 15 bar no problem, no error. (I have the new compressor for 2 days now)
However the MAIN problem is that the car is still sagging in the morning. The reservoir pressure is used to refill the bag every morning, thus causing the compressor to work to refill the reservoir back to 15 bar which in turn can wear out the compressor again.
Please see this video:
https://www.youtube.com/watch?v=EUvxM48eENc.
I think it may be bag since I already inspected all the all other air hose connection points.