Just replace the air chamber.
It is a 40 minutes diy, part is around 180 dollar.

 

What do you mean by "chamber", the bellows (airbag)? If so this doesn't need changing, there is no leak.

 

Is that the solenoid valve on the compressor unit? I was under the impression you needed to replace the compressor as a whole. It does sound like you have a control valve issue that is discharging the pressure under certain conditions.

 

Yes it's a separate component that has an air pipe for both left and right. If I've replaced it with a new one, and still the right side collapse under the same conditions, then rules out the solenoid. Again, the discharge valve does work, but my understanding is that there is only one valve to allow the air to escape, whether it is for left or right side, it doesn't know which side and doesn't care so long as it is allowed to release the air. So something software logical must be telling the solenoid to release the right side only. Changing the compressor shouldn't affect anything, as this only acts on the instructions of the EHC.

The only thing I can think of then (other than the EHC) is the ride-height sensor failing. However, according to the Functional Description of the air suspension, equalisation of the suspension should happen at pre and post mode, and it seems that these are failing for the right side at least, which leads me to believe it is software-related.

Pre mode

In Pre mode (timed initial run / after-run), changes in load are equalised even as the vehicle occupants are getting in and then again for a few minutes after the vehicle is shut down. When the vehicle is locked, the after-run is shortened.

In the Pre mode, the vehicle can only be raised to its specified height if the level drops significantly below the specified height. The tolerance band for the control is approx. 60 millimetres below the mean value. The tolerance band stipulates when the electronic circuitry in the EHC control unit performs regulation. This tolerance ensures that the vehicle is only regulated for heavier loads to increase ground clearance before driving off. Smaller payloads only lead to small amounts of compression travel which are only balanced out after the engine has been started. These control characteristics reduce load on the battery. In pre-mode, only the mean value of the two ride height sensor signals is considered.

Post mode (post adjustment)

The Post mode is used to balance out any inclination before entering the Sleep mode after completion of a journey. The control function has a time limit (approx. 1 minute). In the Post mode, adjustment is made in a defined tolerance band (± 10 millimetres).

It's as if the Pre and Post Mode operations are failing. At one time, the right side actually deflated completely DURING a journey! The EHC should have regulated the height in "Driving Mode" but didn't. This is leading me to believe that this is a software fault, but I would have expected ISTA to produce some erroneous error.

There is talk of the Discharge Valve but I don't know much about this other than the Functional Description on TIS:

Discharge valve

The discharge valve is activated by the EHC control unit. The air escapes from the solenoid valve block via the discharge valve through the air drier.

 

Hello, I have the same problem and mystery deflating + always in diagnose "transport mode active" bo EHC.

Did you resolve your problem ?

 

HI, I'm having similar symptoms too and now that I have ISTA+ I have found that as soon as I disable "Transport mode" the pump immediately comes on and fills up the air bags. The problem is that it appears to periodically go into Transport mode, disabling the pump from inflating any more and causing one or both sides to deflate.

I am targeting my ELM327 bluetooth OBDC adapter that perhaps it is causing a power drain and causing the car to go into Transport mode due to a battery drain. Anyone have any experience with this?
I replaced the Pump, relay and right air bag. I haven't replaced the regulator valve for left/ride side, however I have checked all the lines and valve for leaks - no leaks. I have also hooked up a 12v light to each valve actuator and confirmed they are turning on/off with the pump to fill up only the side that is low.
I hooked up a piezo buzzer to the pump relay so I can tell when the system calls for the compressor to run (I highly recommend that anyone troubleshooting an air suspension issue do this). This helped me identify that the pump is not being called to inflate, even when one side of the vehicle has sunk. Clearing the Transport mode immediately kicked on the compressor.

Does anyone know if targeting Transport mode activation is the right approach and what triggers the activation of transport mode?

 

jfandl - I have exacly the same situation. Compressor starts pumping only when I delete transport mode by ISTA and then delete fault code "transport mode active" in EHC module. I have problem only with passanger side. One month ago I replaced left air spring and 2 weeks later my challenge with fu....ig F11 was began. Right side sagging over night or faster like 1 hour. Yesterday I replaced right air spring for new one but today I saw right rear wheel inside wheel arch... I haven't ideas what is causing activation transport mode and if the transport mode is active, right side is going down. In transport mode rear axle should be rise about 30mm fron normal position. Today evening I'm going to delete transpirt mode and error code, compressor will fill air spring and I will disconnect plug from solenoid block. If the right side will go down, then I replace solenoid block. Both air bags are new (1 month difference between side)..

 

There's a YouTube by "diagnose dan" about diagnosing and repairing the air suspension on, I believe, a 7-Series. Might be helpful...

 

I would not to waste the time today with disconnecting plug from solenoid block and wait to next day with result - I changed valve solenoid block. Then opened the door, pump started, filled both air springs in 50%. Next I run engine, pump starded and filled springs to normal position. Afterwards I did full scan of car via ISTA - no errors found. Then I did small about 10km travel and tomorrow morning I should see result. If right side will be deflated I will burnout bitch to red exhaust pipes and piss of gasoline with words "GO TO HELL !".

 

Still nothing, brand new solenoid block doesn't resolve my problem. Disconnecting battery for one hour also no ***x1f61e;. Right side still sagging...

 

Today I connected to car below handmade kit and pumped right side. Then I close valve and disconnect all from solenoid block (as in picture). If right side drops down again then only two possibilities: banjo bolt/voss because during replacement of air spring I left old voss on pressure pipe (acc to newtis.info) or pressure pipe is somewhere broken.

 

Great idea. Are you able to share any info on how you made your kit? The parts - guessing you had to put a Schrader valve for the bike pump?

Thanks.

 

 

Ok, I resolved my problem. Leaking was caused by banjo bolt / voss connector in air spring. I hope that it will be helpful for you. I prefer you to perform similar test in order to check only pressure pipe, banjo bolt and air spring. Transport mode never came as fault code in EHC module after discinnecting the battery for 1 hour. Regards.

 

Hi Kuchars22. Have you resolved your issue? I have replaced both air-springs, Valve block, discharge valve, done drying of the compressor dryer and changed air-spring banjo bolts as suggested by Mr. efendi (thanks BTW for your contribution), Still right side lower than left. I am left puzzled. When I set heigh in ista, it is all good, once I drive it for few minutes? Right side is lower..... I am pissed off as I don´t know what to change next..

 

We're you able to find a solution? I'm in the same boat!

 

I got a similar ISSUE in my f02 pre... comfort mode saggs one side while driving...or when parked... other modes doesn't!!!
PARKED the car for about a month in SPORT mode still okay!
no errors..etc!