After 15 months of ownership I was having similar problems. It would take over two minutes to go into OR1 and wouldn't go into OR2 at all. The lower levels were ok, albeit a little slower going into normal ride height. I also received the "system cooling down" message on two occasions.
I brought it in to the dealer on Monday and after waiting for two hours left with a rental under the Maxcare Plan. They said the system should have about 130 lbs. of pressure, but that mine had only 30 lbs. It was barely enough to get into normal ride height but not much more. The compressor checked out ok as did all of the shocks. They also said they had never seen this condition before
and that they had to check with Jeep engineers to figure out what was going on.
They called on Wednesday and told me the pump and valve were being ordered and they believed the nitrogen leak was there. I picked it up today and it appears to be working properly right now, but I will be watching to see if it happens again.
BTW, the rental was a brand new Compass...not a bad little SUV but "it ain't no Grand Cherokee". I guess I'm spoiled now. Still lovin' it!