Venturi18

Hi this is my first thread in this forum. I have a weird problem with my airmatic. The car doesn't drop down anything but I ger visit workshop message after a few miles. pulled the code out and I got 5503 central reservior tank filling too long something like that. When I restart the car the message goes away and comes back.

When I push the raise button compressor kicks in and raise up sign shows but nothing happens. I hear a clicking sound every one second from somewhere in engine room when compressor is going.

Hope someone can help on this. Thanx