Another 'selflevel susp inact' thread
 

We bought this '05 X5 3.0 with the 4-wheel air suspension that had a big leak in one of the front air springs (lowrider in the front). I replaced both front springs (with the Arnott spring-only solution) as well as both front axels with EMPI brand.

Got everything back together and used INPA software to activate the pump a few times to pressurize the system. No leaks - good. I reset all the trouble codes and test drove.

However, a day later, the dreaded 'selflevel sus inact' warning reappears. The car has not sagged at all while sitting; so, I don't think I have any leaks.

I pull the code using INPA and then reset. The code is 'filling of reservoir requested, but pressure doesn't increase'. I reset it just to see what happens, but it keeps coming back - sometimes after 10 minutes or sometimes after a few days of driving.

I then fired up DIS and went through the full diagnostic, which tests everything related to this code. Observer pressure in accumulator - OK, 11.6 bar, turn compressor on - OK, observe pressure in acccumulator - 12.9 bar, open dump valve - whoosh, observe pressure in accumulator - 9.6 bar.

As far as I can tell, this error should only be caused by: 1) compressor not turning on when called, 2) big leak in the accumulator, or 3) faulty accumulator pressure sensor. All three seem to check out.

This is driving me nuts!!! Any ideas what else could keep throwing this code. The only other thing I can think of is that I have an intermittent problem with either the compressor (sticky relay?) or pressure sensor (i.e. bad data, but not no data). I guess I have to 'catch it in the act', which we all know how tough that can be...

From experience i would say that the compressor is shot. I had similar problems on my 4.8. When i bought the car the front airbags were totally gone,when the airbags start to leak the compressor has to work a lot harder and longer just to keep the car up. The compressors burn put very easily and quickly. The accumulator pressure seems quite low and similar to the readings i was getting before i replaced the compressor. After i replaced it the readings were more like 14bar accumulator pressure. The car also jumped up very quickly after the compressor was replaced whereas before it was very slow.

Do you still have the fried compressor by any chance. I would like to see if they can be rebuilt. Or are they cheap enough not to mess with?

I was somewhat arbitrary with the pressure readings I mentioned above as I just spouted them off from memory. I'll reset the error and check the pressure again after a drive. I happen to have a spare relay; so, I might as well give that a try, too.

It looks like Arnott sells compressors for $510 shipped. Their site says they from from the original equipment supplier. If I decide to replace the compressor, I'll probably try theirs as it's quite a savings compared to the dealer. Also, the air springs worked out well, except the mounting angle for the air lines was different causing a bit of frustration (line too short on pass side).

Yeah i pretty much tried everything you have before i replaced the compressor.

2 New Arnott bags
2 Front level sensors
New Relay

And then replaced the compressor,unfortunately for me i also had to replace the suspension control module,i've got around $3K in the suspension so far,touch wood its going fine now.

The arnott compressors are a much better deal than the stealers,i don't know how they can justify the price when an aftermarket supplier can sell them for nearly half price.

can someone post a link to this Arnott stuff? Just as a reference. I am sure others like me will be looking into this in the future.

Also, how does one reset codes on these cars? Do I need a BMW reader or a regular ODBII scanner will work? I doubt it though.

BMW Air Suspension Parts & Kits - Arnott Industries

You'll need more than an OBDII scanner as those just cover engine/emissions stuff. I use BMW DIS/INPA running on a laptop.

Thank you. Will DIS/INPA read the transmission temp sensor as well? I guess I have enough info to search. Thanks again e39_touring.

Yes, it will, and you need this for filling transmission to the proper level.

OK, I'm still keeping my fingers crossed that I don't need a new compressor. Here's what I tried yesterday:

Cleared the trouble code. Started the car and changed the height several times - access/normal/high. The compressor ran a lot. Drove around a couple of miles. Reconnected and read accumulator pressure - it was 14.6 bar. That does seem to be a little low as I understand operating pressure is 15.7 bar + or - 0.7. Using INPA, I ran the compressor and increased pressure to 16.4 bar, but I did notice that after playing with it a lot, it heats up rather quickly.

With the pressure properly set, my hope is that the compressor won't need to run as much and won't trip the code (or at least not often). I would also think that the code I would be seeing is 'compressor overtemp' or something like that versus the 'accumulator filling requested, but pressure does not increase'.

Neil, why did you end up replacing your control module, too?

I get the same error from PASoft for my 2-axis EHC. I haven't replaced my compressor but it's the last thing on my "list." I've replaced the EHC-II module, 2 front struts, accumulator sensor, valve block, relay. All except the struts were done under my extended warranty.

My friend/indy re-coded the EHC and the problem hasn't surfaced since, but he and I agree that if it comes back, it's 99% the compressor.

I have a compressor and relay under the passenger seat to sell.

They both have around 38k miles on them and are in great condition. I just have them sitting in my storage room so we can work out a good deal.

Let me know!

pm sent on the compressor!

Anyone know if there are TSB's issued on this problem (fault code for filling of accumulator, but all components go through diagnosis OK)? I might have to get the day pass to bmwtechinfo and see what I can find.

The warning message came back after about a day of driving short trips/errands. Same error code stored, and accumulator pressure was at 12.7 bar. I was able to pump it back up to 16.0 bar with ~1 min compressor run time and an increase in compressor temp from about 4 deg C to 40 deg C.

Well, here's a follow-up that I hope others can benefit from. Neil48is hit the nail on the head (thank you!) After a long roadtrip, Seattle to Albuquerque, with laptop/INPA in tow, I finally caught it in the act. I open the pressure reservoir valve, and I can hear the click and see the pressure drop as the line to the compressor backfills. So, I know the valve and sensor are A-OK. Then, I run the compressor to repressurize the reservoir, and, occasionally, the compressor would run but not increase the pressure in the tank.

I put in a new compressor from Arnott and noticed it does accumulate pressure more quickly, and the dreaded light has been off for two weeks!

Congrats! If only dealers have this common sense for diagnosing instead of relying the the BMW TIS/DIS process.

Was installation of the Arnott compressor straightforward?

Congrats! How straightforward was the compressor to replace? Thanks for posting in my thread and giving me hope!

At least someone finally had the same code as me! I may replace the relay too to be safe, do you have a part number for it? And the location is in the padded envelope next to the battery right?

The Arnott compressor was a snap to install - just a couple of things to note: 1) they no longer include the air line release tool that's mentioned in the instructions. You don't need it. I was able to slide the quick-release fittings back with my fingers. And, 2) for a cleaner installation, disassemble an old telescoping radio antenna and use one of the tubes to release the two wires/pins from the electrical connector. Without this, you'd have to cut & splice two wires - yuk.

Ricky Bobby - if your compressor is turning on, the relay is fine. The relay's pretty cheap, but I doubt you need to replace it.

Do I need to depressurize the system first? Or just disconnect the battery and install? If you have any other details to share I would greatly appreciate it, thanks for all the help so far!

So since you have replaced everything, your ride height function works? Did it work at all with the "self level susp inact" warning on? Because mine has never worked since I bought the truck! haha

Thank god the previous owner replaced the module, now after myself using Arnott for the front struts and now possibly the compressor I may have hopefully fixed the air suspension for now!

Ricky Bobby, check here: Air Suspension Kits, Air Shocks, Suspension Parts, Struts - Arnott Industries for the compressor that we speak of.

I'm using Arnott front strut on the pass. side.

Here's a link to the compressor install manual:

http://www.arnottindustries.com/file...617&Size=SMALL

I didn't need to depressurize the system as there is usually no pressure in the line between the compressor and reservoir tank. I suppose if the reservoir valve is bad, you could have pressure there but that doesn't sound like your case. I didn't even bother disconnecting the battery since you are not disconnecting the control module.

My ride height function works/worked as long as the selflevel susp inact message was not illuminated. When that message shows up, the whole system is turned off until you reset it with a dealer-level tool. Everything works fine now - I only replaced the two front air springs and the compressor.

I read their install instructions, just wanted to know if you depressurized the system beforehand, or just disconnected the battery. I would like to replace the compressor myself since you had the same code as me (accumulator filling requested, pressure remains constant).

Just wondering if i need to take any additional steps if when I decide to replace the compressor, or if I can just disconnect the battery and go to work! Then reconnect the GT1 to clear faults after :)

Nope, I didn't need to depressurize or disconnect the battery (tho can't hurt). It's an easy job and took me less than an hour.

Once the new compressor is in, clear the fault with GT1, and enjoy your ride-height control and an instrument cluster that's not always screaming at you!

you are my new hero if this works. makes total sense since the previous owner had leaky front struts for god knows how long before I bought the car from him, the compressor probably burnt out)

(updates coming soon)

Let me know if you need my compressor :)