Another 'selflevel susp inact' thread

e39_touring · #1 11-16-2011, 07:13 PM

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...

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Neil48is · #2 11-17-2011, 05:16 AM

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.

SlickGT1 · #3 11-17-2011, 11:02 AM

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?

e39_touring · #4 11-17-2011, 11:40 AM

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).

Neil48is · #5 11-17-2011, 01:19 PM

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.

SlickGT1 · #6 11-17-2011, 03:50 PM

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.

e39_touring · #7 11-17-2011, 04:02 PM

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.

SlickGT1 · #8 11-17-2011, 06:37 PM

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

e39_touring · #9 11-18-2011, 11:39 AM

Quote:

Originally Posted by SlickGT1

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.

e39_touring · #10 11-18-2011, 11:52 AM

Quote:

Originally Posted by Neil48is

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.

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?

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