W220 airmatic fault

[Robiduff]

Hi, my 2001 W220 just got an airmatic fault alarm. No fuses are broken and the I'm guessing the relay's are ok since i undid the connection on the left front side and air was comming out. The car is as low as it can go on all wheels.

what can be the fault if the pump is running but the car is still low on all fours?

 

[ItalianTuneUp]

Has the car body been going down overnight recently before this happened?

One thing you can do is check for cracks in the top of the front airmatic struts: left and right big round things under the bonnet.

If the car is going down on all four corners (front and back of car) then the leak is likely in a common area of the airmatic system, frequently this is due to a leaking valve block, which distributes the air from the airmatic compressor.

But let me know if this is a sudden thing or whether the car has been dropping over a period of time.

 

[Robiduff]

the alarm went on and off very fast a few times during 2-3 days, untill the last time it got permanent and the car got as low as it can go.

The airmatic struts are ok, i checked both of them.

I was suspecting the valve block or maybe the hose from the pump it self.

There is allso a kind of ticking from the rear part of the car when the engine is running, I don't know is this can be in connection with the faulty suspension?

 

[ItalianTuneUp]

When you see the car in the mornings now, is it down on all wheels?

When you start the ignition, does a red message appear saying airmatic body too low? And then does the body rise?

 

[Robiduff]

it's allways down on all wheels, it never rises. the red message is allwyas on as long as the ignition is... when i start it nothing happens. I tried to undo one of the hoses to the front suspension, and there was air comming, so im guessing the pump is running. So it must be a leak then?

 

[ItalianTuneUp]

There may be multiple leaks, but body dropping on all four corners is very frequently caused by a leaking valve block.

If you take it to MB and ask for an airmatic leak diagnosis it will cost circa £100, and you can ask them to check the valve block first, which may reduce the cost as it is likely the cause, although not necessarily.

 

[ItalianTuneUp]

To me, sounds like either the valve block is leaking, or some common air supply tubing, the leak diagnosis will discover the cause.

You can spray soapy water onto the valve block yourself if you want to check this yourself...it's on top of the airmatic compressor behind the offside headlamp.

 

[Robiduff]

Ok, I will try to test this first. Thank you so much

 

[ItalianTuneUp]

Another possibility is that the compressor pressure has dropped and is unable to raise the body.

If you visit mb or garage, get them to replace the airmatic relay, as it's cheap and the older relay (Siemens?) is a known point of failure. The newer one is made by Hella. Cost is about £10. The part number for this airmatic compressor relay should be [FONT=&quot]A002 542 72 19[/FONT]. That's what I had fitted on my facelift 2005 S320CDI anyway.

Good luck and let us know how you get on, as this can be a worrying and irritating problem - I've been there, done that and got all the T-shirts

 

[ItalianTuneUp]

I don't know about the ticking noise from the rear of the car. It could possibly be related to the airmatic leak, but perhaps you've only just noticed it now?

If there is such a big leak that the body won't rise then it could be that the airmatic compressor is constantly pumping air trying to fill the struts, and this is a possible cause of the ticking noise, but this is just a guess.

 

[V12]

Sounds like compressor relay would be first thing to check.

Can you hear the pump running?

Start the car and put your head by the drivers side front wheel/bumper. If you can't hear the compressor then I would first change the relay.

 

[Robiduff]

Ok, first i found one mistake, the pump was NOT running, i just thought so becaus air was comming out from the hose, but it was just left overs, i tried again no and the air stopped commin after a while. when i took a look at the pump it was not runnning. The relay was the new Hella type, and it was ok, measured it to 87 Ohm. the fuses are ok. But one connection to the pump had a worn wire, when i pulled it, it came right off. I'm guessing this cable had something to do with it... i think it is the power supply to the pump so, at the connection it says 2 and 1 above the cables. I will try to fix these cables and connect it again

 

[ItalianTuneUp]

Good news, so it could be a simple electrical fault with the compressor wiring. Cheap to fix

 

[Robiduff]

it was still connected but only barely, so im hoping thats the problem This forum is the absolut best way to figure things like this out! thanks to both of you

 

[V12]

You can put jump leads straight to the compressor and see if it runs.

 

[Robiduff]

I tested it now with new cables, and it still did not run. I measured the kables to the pump and it was no power supplied. So when i had a look at the relay i saw i can't just measure it to see if it works, there was power supplied to the relay som im guesing thats were it stops, so im replacing that tomorrow

 

[ItalianTuneUp]

Did you try taking power direct to the pump from jump leads, bypassing the relay? Just to see if the pump works? So could it be a faulty fuse?

Sorry, just re-read your post. So it seems to be a faulty relay then? Relay part number: A002 542 72 19

 

[Robiduff]

yes, well, I measured the cables to the pump and there is no power supplied to the pump now... , i have to find the problem with the power first. so im going down to MB now to get a new relay.

 

[Robiduff]

Hey guys, new update. I replaced the relay, so now i get power to the pump13-14 volts measured, but it still won't run... can it be dirt stuck in the pump so it's an idea to remove it and see if i can get it moving or is it most likely the electric motor that is broken and there is nothing to do but replace it?

 

[ItalianTuneUp]

Maybe the relay failed and then this burned the compressor out by making it run continuously? I'm not sure if that's possible with a relay, but I think I read that having a failed relay can destroy your compressor, so maybe that's what happened in this case?

Maybe someone else can confirm this is possible, or do a search?

Is there a fuse for the compressor anywhere? If so, maybe check the fuse first.

Edit: see if this helps. If not, I have some html works manual for the w220 I can check to see if the location of these fuses is mentioned.

http://forums.mercedesclub.org.uk/showthread.php?t=65556