X5 F15- intermittent Chassis Restriction Fault

s29uny · Post by **s29uny** » Mon Apr 01, 2024 8:09 pm

Hi all.

i'll try and explain in as much detail what has happened - hoping it is enough for someone to help.

Yesterday i went to see my sister, her house is on a fair gradient, usually i park in her driveway but this time i parked on the left hand side pavement - now that i think of it, the passenger side wheels were more raised than the drives side.

After a few hours of being at her home, i began my journey home and found the ride to be slightly more bumpy than usual, not thinking anything of it i continued with my journey.

Today i got into the car, everything seemed normal but after a few minutes of driving the ride was noticeably more bumpy. I pulled over to see why, it was then i found the car leaning to the left (as you are looking at it from the front).

i tried to let the car 'rest' for 10 minutes with it being locked to see if it fixes the issue but it didn't. The drive became more and more bumpy, but for the 30mile journey to my in laws to pick my wife up, apart from the very bumpy ride everything was fine.

When we left my in laws for the return journey home an error message 'Chassis Restriction' presented itself on the iDrive.

The drive feels very similar to when my f10 5 series snapped its rear spring - if i drive through a pothole, or uneven ground its like i am in a car with zero suspension.

The car has been now parked on my driveway for the last 2 hours and its still sitting very low.

As its only just happened, i have not had a chance to take to a garage to get the fault codes read, but to save me from having a nasty surprise, any idea what the issue could be?

s29uny · Post by **s29uny** » Mon Apr 01, 2024 10:16 pm

A quick update:
I just went outside to get something out of the car, the rear was completely slammed to the floor - i couldn't even get my 2 fingers between the top of the tyre and the arch.
As soon as i opened the drivers side door, i heard the compressor going off, and the car rising to level, but then the hissing sound followed on the left side of the car. I locked the car and the compressor switched off, at which point i could see the car lowering itself again.

Surely it has to be a leaking bag on the left side?

Alan Gunn · Post by **Alan Gunn** » Tue Apr 02, 2024 6:09 am

Yes a bag leaking.
Common problem but not a bad job to change.

IanP · Post by **IanP** » Tue Apr 02, 2024 6:50 am

I agree, an air bag seems to have popped, assuming one of the air pipes isn't damaged.
I've just done this job on my X6 and it is very straightforward took me about 1.5 hours but I did have access to a car lift.
I fitted Arnott bags, not genuine bmw.

Leslie · Post by **Leslie** » Tue Apr 02, 2024 5:03 pm

Sounds very like an airbag and id recommend arnott bags as said... very good quality, the cheap ones tend be be far thinner and "pop" in a relatively short time again.

s29uny · Post by **s29uny** » Wed Apr 03, 2024 5:19 pm

Hi everyone.

a quick update. i jacked the car up, and sprayed some soapy water on the bags, activated the compressor. Left bag was leaking air. i purchased Arnott bags and replaced both of them.

not a difficult job, just too some time making sure they were sat right.

Thanks all for your help.

Alan Gunn · Post by **Alan Gunn** » Thu Apr 04, 2024 6:01 am

Hope you fitted any new "O"rings that came with the bags.
Re-using them can leak.

iamwestone · Post by **iamwestone** » Mon May 06, 2024 5:28 pm

I had the same problem on Saturday morning. The intermittent Chassis Restriction Fault message started a day or 2 earlier but I wasn't able to get it booked into a garage until next week. The car felt like it was sagging to the back left slightly and the ride was a bit lumpy. On Saturday morning I noticed it was sagging much more and every bump I hit caused a very worrying knock from the back left wheel. I managed to get it to a Kwik-fit and when I got out of the car and looked at the back left the wheel arch was almost sitting on the wheel. The mechanic there said it's probably an air bag/spring but not something they can do even if they has the parts so I limped home in it.

Weirdly though - today the back left wheel arch looks to be a normal distance from the wheel, although maybe still a slight sag. So somehow the bag has reinflated. Does that suggest a slow leak on the bag or could it be something else?

Assuming the answer is to replace the bag can I just replace one or should I do both? Does the Arnott replacement on one side and the original part on the other make any difference?

IanP · Post by **IanP** » Mon May 06, 2024 7:30 pm

Mine used to randomly drop or stay up for days. Problem is if it has a slow leak then the pump will be running a lot and it's not really designed for that.
As for changing one or both, if one has a leak and they are both the same age, then I would doubt the second one will be far behind in failing....

iamwestone · Post by **iamwestone** » Tue May 07, 2024 7:49 am

Thanks Ian. I guess it's easier if they do both at the same time if they have to disconnect the compressor and air lines etc.

Leslie · Post by **Leslie** » Tue May 07, 2024 10:34 pm

I just did 1 and its been fine a year later passenger ones tend to take more of a hammering with potholes .

iamwestone · Post by **iamwestone** » Mon May 20, 2024 2:04 pm

So the car went into the garage a couple of weeks ago and they replaced the passenger side bag. It seemed to have fixed the problem on the drive home but the next day the Intermittent Chassis Restriction Fault message started appearing again and the car is visibly sagging to the rear left (although not as low over the wheel arch as it was before). The drivers side arch looks very high over the wheel in comparison.

What could the cause be if not the air bag? Could there be a leak on the air line that supplies the passenger side bag? Or could there be a faut on the driver's side bag that is over-loading the passenger side?

Thanks for any help!

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