It shouldn't lower at all... I regularly don't drive mine for a week plus at a time and it doesn't drop an inch. Well I shouldn't say "not at all" it'll wake up after sitting 6 hours and self level which may cause a corner or end to drop slightly. Either you rig has a leak, or during the "wake up" period a valve in the suspension block is sticking causing the whole system to deflate. This will especially happen if there is moisture in the system and it is freezing out or contamination in the system has built up. During wake up it'll sense a corner is high and attempt to lower, the relevant valve opens then seizes in the open position causing the suspension to completely deflate. You maybe need to pull the valve block and either rebuilt/clean, then moving forward fit a new air drier to the compressor. I also suggest drilling a hole in the compressors exhaust valve.... That can get blocked with junk and cause all sorts of strange EAS issues. Or... you have a leak.

 

...it'll wake up after sitting 6 hours and self level which may cause a corner or end to drop slightly... During wake up it'll sense a corner is high and attempt to lower, the relevant valve opens then seizes in the open position causing the suspension to completely deflate...

The truck maintained its level over-night in my garage so I don't think I have a **big** leak.

But, especially since I don't understand how the air suspension is supposed to work -- "wake up" mode and so forth, I would very much appreciate it if you could point me towards a resource that might describe this behavior.

Indeed, the truck seems to do lots of "stuff" when say, a door or hood is opened or closed (like the blower sounds like it turns on briefly when the door is opened) and I would like to understand what it's supposed to be doing (I've never had a vehicle with all these "luxury" features before).

Many thanks from this intimidated newbie.

 

It should not lower at all if you have no leaks. If you have a leak or leaks one corner will drop the EAS will lower the other corner to maintain being level. When lower the cracks that are leaking close up. Thus the reason it raises quickly. Unfortunately your compressor has to work over time to keep the reservoir full and keep up with the leak as the bladder flexes driving at normal height. You will need to identify which front strut is leaking. Inspect them closely for cracks at the bottom of the bladder where it rolls. If these are original struts from 2006 I would replace both front struts and be done for another 80K miles. Rear EAS usually far outlasts front.

 

Mine def lowers and doesn't leak. My garage floor is graded for a drain where I park it. I've been in the garage working on another car when the rover wakes up and lvls out due to the uneven floor.

 

RRToadHall described my rig to a T. What I suspect is the strut bladders only move a fraction of what their full travel is and as a result, they develop cracks in the wrinkles. I paid to replace the fronts and no issues with the rear. On my P38 it was an easy job.

 

The struts are easy enough to diagnose... just spray them down with soapy water and look for bubbles. My original struts had cracks and dry rot for literally years before they finally failed.

 

The truck auto levels every time you turn it on and off.

 

I've heard (or at least think I've heard) it leveling when opening the right rear door and closing the hood. It apparently also "wakes up" every few hours and levels itself, too. I'd love to learn more about those kinds of behaviors.

FWIW, the truck sat for 48 hours until this AM in my sloped front yard and seemed to maintain its suspension height.

 

Pulling the EAS fuse and letting it sit will let you see which corner (or end) is the culprit if you are able to let it sit for a while. The system wakes up two hours after shut off and checks the height sensors and will lower them to meet the lowest one. If that one continues to leak, all four corners will continue to lower over time when teh system wakes up (6 hours after the initial 2). By pulling the EAS fuse, the self-lowing behavior is stopped allowing you to isolate the corner. If both sides of one end go down (front or back) then it is likely a valve block.

 

Please expand on your comment to drill a hole in the compressor's exhaust valve. Did you mean enlarge the existing hole? Where is the exhaust valve located? A photo would be nice. I've been having an issue with the air suspension (Suspension Fault message) for over a year and cannot find the cause. The system seems to be working properly, raises and lowers on command, and stays in the selected position. Any advise would be appreciated.
2007 RR/SC

 

If your air struts were replaced 21K miles ago, then I would look elsewhere for the leak (air struts last anywhere from 75-99k miles). Most likely the air suspension tank is the culprit. It rides underneath the truck (not the most ideal environment) making it susceptible to all sorts of environmental assaults like road salts, stone chips, etc. Considering you have a 2006, I would at least inspect it before looking anywhere else for a leak. Here is what a bad one looks like and how to replace it (I believe vehicle featured in the video is the same year as yours):

https://m.youtube.com/watch?v=HaagkLFlYIY&t=340s

 

Three front Arnotts in 6 years. There will not be a fourth. I found some off brand strut with airbag for half the money on Amazon. Hooked right up and took me about 1.5 hours including test ride. Cant tell the difference in ride comfort at all. Raises up and falls at the same rate as the other front.

$232 shipped to my door. I pity the fool who pays $2k an axle. Its not a difficult job, especially if you watch a few videos.

 

Three front Arnotts in 6 years. There will not be a fourth. I found some off brand strut with airbag for half the money on Amazon. Hooked right up and took me about 1.5 hours including test ride. Cant tell the difference in ride comfort at all. Raises up and falls at the same rate as the other front.

$232 shipped to my door. I pity the fool who pays $2k an axle. Its not a difficult job, especially if you watch a few videos.

I know it's only been a couple months since your post. But, how are these holding out for you? Info on brand/manufacturer or link to product?

 

Are Arnotts starting to make crappy air struts? I've had no problems on my BMW wagon for over 100k mi on Arnotts, wondering if their L322 line is of subpar quality?

 

Yes, more and more L322 owners are reporting here that their Arnotts have sprung leaks.