Air suspension having problems

X5Sport · Post by **X5Sport** » Thu Dec 24, 2020 9:36 am

Most modern main dealers/garages have no idea on how to work from 1st principles for fault finding. They rely on the computer to tell them everything. If the compressor is running then it’s running. A pressure check will prove whether it is running properly. If it is spinning up then it can only be seals leaking the air and you can buy seal kits (though not from BMW).

Part of the issue with modern cars is the fixed time allowed for servicing and the fact that BMW only replace not repair so no one learns how to identify underlying faults. A good dealer should have a Master Tech and that person should know how to fault find. In the past I have had long conversations with the MT and worked back to the fault. It helps with me being trained as a mechanical and electronics engineer though as I can ask the intelligent questions that Dealers detest - such as ‘how do you know it’s really the compressor? What checks have you done to prove it?” And of course the one they really hate - “if you’re wrong then I’m not paying for your misdiagnosis or the parts, you can put it back together again!”

Leslie · Post by **Leslie** » Thu Dec 24, 2020 7:52 pm

Reading back you only swapped the sensors side to side over never changed any is that right ? , given these parts are wearing parts with all the suspension movement and I'm guessing a lot cheaper than a compressor . I know it keeps saying left rear but I guess all sensors need to be reporting for any decisions to be made so if one is out all out . Looking at the pics of pumps on ebay its looks to me to be just a pump like an e70 , all it does is pump when told too ... If your bags are lifting you have pressure , how much its hard to say but enough to do by the sound of it otherwise id expect a suspension control inactive alarm which is what my e70 reported.

I be loath to change the compressor just yet given the huge cost (you may have to in the end) and given the cost from bmw id be looking elsewhere , I got a good new amk compressor for my e70 for £330 2 years ago , there were cheap ones but these are best avoided ( eg aerosus )

X5Sport · Post by **X5Sport** » Thu Dec 24, 2020 8:53 pm

BMW’s own service manual says that changing the sensor over (even if just disconnecting it) requires the ride height calibration to be redone using their diagnostics.

Bch06 · Post by **Bch06** » Mon Dec 28, 2020 2:53 pm

I will be going tomorrow to the dealer as they were closed from last 4 days, I will again put my question to them to explain me why do they think it might be the compressor, Since they are not certain and If they refuse to answer my question can I disagree to pay the diagnosis charges? But I still want the problem to be fixed.

I have also done a lot of research and found out that the air compressor not only pumps air in to the bellows, it also has a function to purge the air and in my case that is the problem, even when I run the deflate cycle through Ista D the car doesn’t deflates, so I guess it is the deflate function which is playing up. However when I last opened the compressor I didn’t see any sign of water but I still replaced the desiccant silica gel beads, it must be the solenoid valve which is stuck closed and doesn’t let the air purge.

Leslie · Post by **Leslie** » Tue Dec 29, 2020 1:30 pm

I hope they get it sorted , it can be a right pain the same fault dragging on and on , I'm sure they must have seen similar issues in the past and there quite possibly is a deflate function

Bch06 · Post by **Bch06** » Sat Jan 02, 2021 1:56 pm

I went to the dealer, so I can speak to the technician, however they refused to let me speak to the technician, I did argue with them about the diagnosis but in the end I decided not to waste my time and more money and just paid the £99 diagnosis fee and got the car back.

From my experience I say dealers are useless, they only told me what the see on the computer, which I already knew from ISTA D. They quoted me £850 for the compressor & £250 for install the compressor (really to unscrew 3 nuts and screw them back £250) yes unfortunately they are the biggest ripoff

As I previously informed on this forum that I was researching on how the compressor works and found out that the compressor actually also has a deflate function, which strangely not has been discussed on any online forums, I decided to order a part called “Air Compressor Vent Valve” it’s available on online shopping websites and it costed me £30

Today I took out my air compressor unit to reply the vent valve on the compressor, when I compared if with the new one I could easily tell that the new one was moving freely and the old one was stuck closed, I have taken few pictures which I will upload, I fitted back the compressor unit on to the car and went on a long drive, no errors, ride height is on correct level and smooth drive. Yayyyy

Although it took me quite long to resolve this issue, but in the end hard work and research paid off, thank you everyone for all the advice.

X5Sport · Post by **X5Sport** » Sat Jan 02, 2021 3:48 pm

Perhaps you ought to go back to the dealer and tell them that their diagnosis was wrong and what the actual issue was - and the repair bill. This is the sort of incident that should get into the motoring press too, as well as being reported to BMW GB as it brings the whole, and repeated, question about dealer technical competency into more focus.

The motor trade simply does not care, nor is it prepared to sort itself out and with no regulator, why should it?

Glad you’ve got somewhere

If BMW stopped focussing on shutting websites that have copies of the technical instructions details that ‘intelligent owners’ need and want and give us the ‘right to repair’ what we own, but instead spent time and effort on fixing the standards in their Dealerships, then maybe the public would have a bit more faith and trust in them. Fleet buyers don’t care, but the private owners should not be treated with such contempt.

I suspect - and this is based upon previous conversations with BMW GB - they simply don’t give a sh!t.

Leslie · Post by **Leslie** » Sat Jan 02, 2021 6:16 pm

Good work and if that's it a grand saved! BMW were sort of right in that a new compressor would fix it but at huge cost.
Definately the first time I've heard of this vent function so fair play and as for 250 to fit a compressor it's the silly hourly rate and as we often suspect the price isn't always reflected in the amount of expertise provided

To give them a bit of credit though if they replaced that part and the compressor failed a week later you would be pissed and all they mostly do is warranty work where the customer isn't paying so couldn't care less.

Isra93 · Post by **Isra93** » Sat Feb 05, 2022 9:34 pm

Hi all,

Did anyone manage to fix this issue ?
I’m having a exactly the same problem and I have been told
to replace the compressor ?

Thanks

Leslie · Post by **Leslie** » Thu Apr 14, 2022 1:02 pm

Have found a great how to for the f15 air suspension compressor explains how it works and what goes wrong ,thought it was worth a share as all that generation of cars share the same system

It mentions the discharge valve and how to test as well .

https://www.youtube.com/watch?v=jBzNmhH7J-0

Walshy5050 · Post by **Walshy5050** » Sat Sep 30, 2023 5:04 am

This is tge issue I'm having iv replaced both ride hight sensors and rear air bags. Now I have to find this valve.
Great work
Thank you

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