4.4i Rear Air Suspension Puzzle.

[DGParker]

Hello E53 Forum!

I'm a new member here, this being my first post. I wouldn't consider myself a guru mechanic but I have been working on euro autos for 12 or more years. I have done many restorations and repair jobs and am very familiar with most things in that realm. I am new to the BMW air suspension world so I am slightly out of my area of knowledge. I understand the systems well but still seem to get stumped with my situation. Any enlightenment would be very much appreciated!

I have an 03 X5 M62 4.4i w/ sports pkg. I bought the car used for 14k a year and a half ago. I have been proactively replacing essential parts since I have purchased it. I have replaced all components in the front suspension with new parts 6 mo's ago. I was saving up to do the rear when the infamous rear air suspension issue reared its ugly head.

Started off sagging over night, mainly on PR side. Unlocking would raise it and it would be fine. There was no "inactive" message yet. The next day it was down and wouldn't raise when unlocked. I was forced to drive it for 2 days, due to no extra vehicle, with the rear low. On the 2nd day the "inactive" light came on for awhile and raised the bags. I did some research and the truck sat til the weekend and I replaced the bags and the level sensors on both sides with all new parts. After installing and lowering the jack, the rear pumped up and i thought job well done.

The next morning its back down. Unlocking raises it and Ive done that every day this week. I go out this morning and down as usual. Unlock and nothing. I know the compressor is fine because it has been coming on fine and only runs for a few seconds each morning and its off. The bags and sensors are new. I don't have a diagnostic tool so I cant do any clearing or adjusting without going to an Indy or Dealer. All fuses are good. I don't hear hissing and have been trying to find a leak in a line with soapy water but nothing so far. Could it be the pump relay? Is there a solenoid or something that keeps the air in the bags while asleep that could have failed? Is it serious like the control unit? I would really like to exhaust my options as much on my own first before breaking the bank to get a pro involved. I will if its a necessary step but hate paying fortunes for what I'm completely capable of tackling myself with the proper knowledge.

A little guidance would be very much appreciated! Thank You!

[TwinTurboGTR]

Welcome to the forum. Now when you replaced the bags. Who did you buy the bags from? The solution of soapy water, was there enough soap. SOme people just don't add enough and the surface tension of the bubble can't form. Are both sides lowering or just the one side? Can you snap a picture of what it looks like lowered and what it looks like when it is raised?

[DGParker]

I purchased Arnott rear air springs for sport suspension. The sensors were OEM. Everything went on fine and I triple checked all connections. I will try more soap in the water as a precaution. The PR side is the lowest side but DR side is low as well. I don't have a picture of it raised because when I unlock it nothing happens now. Even starting engine and driving it won't raise. I measured the gaps after the install and both sides were at 4.25 inches roughly above tire.

[DGParker]

Ok, small update.. I retested the lines for leaks with soapy water. Still no noticeable leaks and I used lots of soap this time. I decided to pull the compressor out of its shell and turned it over to access the relay. I pulled the fuses and then the relay and checked them out again. I scratched the terminals with sand paper just for fun and then put the fuses back in. I jumped the relay to test the compressor. It kicks on fine doing that. Did that about 4 or 5 times in small bursts of about 20 seconds. Rear didn't seem to lift up while doing this. I concluded that the compressor is ok but Im still a little unsure if the relay is working properly. I put the relay back in and buttoned the compressor shell back up. I can not find anything noticeably wrong with everything I just looked at. Once I had it all back together I tried to get it to raise by unlocking it. Nothing happen. I pulled the jack out and lifted the PR side off the ground. Waited a few seconds and then lowered it back down. The compressor kicked on and raised the back end..... .....

I am still confused here.. I also talked to an Indy shop and they said I've done pretty much everything they would have done as well. Should i pay to have them hook the GT1 up and check the system out that way or is that wasting time and money? Am I missing something obvious here or is this some kind of electrical nightmare?

I snapped 2 more pictures while the vehicle is raised for comparison.

Im going to go beat my head against my wall for a few...

[TwinTurboGTR]

Ok, that is the correct procedure. To fill the bags, for most, the X has to be lifted a bit for the computer to compensate.

Now Arnott are good bags but sometimes the band collar that secures the rubber bag to the strut is clamped on incorrectly and allows air to escape. But it doesn't sound like that in your case. Now some have also complained that after a R&R with Arrnot, their system needed to be reinitialized in order for the ride hight to be correct. Let someone else chime in to see if they concur.

Most of the time this happens when someone changes 1 spring but keeps the original. After getting everything back in place, one side is higher than the other. Normally the higher side was the original bag.

[TwinsPoppa]

DGParker you're kind of local to me. I'm willing to diagnose with GT1 if we can agree on a place to meet. PM me to work things out.

[Ahmed303]

Sorry to resurrect this old thread but I am having the same issue. Was there a resolution to this?


The Passenger side rear will sag overnight but not every night. It seems that the X has a mind of it's own. Any help is highly appreciated.

Thanks in advance.