I have a S212 2012 4matic cdi, the car had suddenly dropped down completely while I was in the store, when i came out and started the car i noticed the message "please wait while raising" or similar, later the message malfunction showed.
the compressor doesn't come on. I've checked some fuses and the relay, I got a measurement from pin 86-85 on the relay, and 6.* volt on the 85-86 pins in the relays socket.
So I'm kind of afraid that the compressor has failed, right?
My car pc is at home that's 600km away so I cant use that to diagnose the car.
is there no way to raise the car so I could at least drive around the part shops looking for another compressor?

 

I never got my hands on Airmatic W212, meaning I have zero experience with Airmatic ..... but I will try my best to help you based on the WIS I can find.

I hope the Airmatic wiring schematic I am attaching is the correct one for your car.
Without your car VIN, I only know your car is a station wagon 4-matic diesel, but I do not know anything more on other options which may or may not lead to a different airmatic configuration.

Let me explain slowly as to how you should approach this issue.

You wrote :
1AA. I've checked some fuses and the relay, I got a measurement from pin 86-85 on the relay, and 6.* volt on the 85-86 pins in the relays socket.
1BB. So I'm kind of afraid that the compressor has failed, right?


1AA. I am assuming you are talking of the K67 relay ? That is the only relay for activation of the air compressor and that is a stand alone relay not part of Rear SAM or Front SAM fuse boxes.



See my label 1 on above schematic..
The K67 relay control or coil, the 85/86 is totally powered both wires by the N51/3 Airmatic module, that power feed is not for the air compressor, only for the relay coil.
"I got a measurement from pin 86-85 on the relay, and 6.* volt on the 85-86 pins in the relays socket."
I assume you are measuring that voltage while under load , meaning relay is not plug out of its seat and the compressor is somehow being commanded for activation.
If indeed my assumption is true, the low voltage command to relay pin 85/85 is from and by the N51/3 module and that should not be the case, the command should be battery voltage 12.xx volt.

Please check 2 things. First see label 2. That is the power feed for air compressor A9/1 coming from F32 Front PreFuse block fuse 160 or 162. This feed goes into pin 30 of the K67 relay.
You need to check if the battery voltage (+) is available at pin 30 or not.
You also need to check if pin 87 of relay K67 gets proper ground or not. Pin 87 to car clean unpainted metal, using resistance/ohms. What is the reading.
Do bear in mind this test on pin 30 and 87 is not a loaded test, so it may show good result when under no load from compressor operation and may drop voltage a bit or a lot during compressor operation,
depending on how clean and tight are the connection at all the splices of positive power labeled as 2 in red and the ground feed labeled 3 in blue at W6/4 ground stud.

Now, we go back to : "I got a measurement from pin 86-85 on the relay, and 6.* volt on the 85-86 pins in the relays socket."
As I said that the power for pin 85/86 is from N51/3 module, you need now to check the power feed for this module. See below label 4 and 5.



Your must measure the voltage at N51/3 module pin 47 (+) and pin 21 (-), see if you have proper battery voltage into it or not.
This power for N51/3 is from fuse 68 at Rear Sam fuse box. Make sure it is sitting properly and the contact is clean.

===============

If you want to "jump" the compressor MANUAL way, you can. But at your own risk because the power is big.
If you have a wire with fuse to assist, you may try. Minimum 4mm wire and 30 amps fuse, if not 40 amps.
Pin 30 of relay K67 is always ON/HOT assuming its fuse 160/162 is not blown. If you connect (jump) a wire between pin 30 and pin 87 of the K67 relay, basically you provide power for your air compressor.

Good luck.....

 

What do you mean by car dropping down completely? All four corners down?

If that happened something cut all air lines to all springs or the valves in the block opened at the same time and let air out, which is hard to believe.

It is alsdo hard to believe someone would cut all air lines to your springs but there is vandalism and some crazy people could do that.

Your compressor stopped because it timed out trying to raise the car. If it has to pump all four springs up at the same time it might not get to the right level in time limit or heat limit it has.

But, I would be worried why the car dropped down to start with? Compressor has nothing to do that.

Check your air lines to springs. In my car the valve block is in the rear of the car behind the bumper. All air lines come to it and you can access it from below. It would be easy for some crazy person with just one knife strike cut all air lines to all springs and compressor.

 

Dang man thank you so much for this, did not expect to get this detailed help, I apologize for my late response.
I tried my best to do as you instructed.
I'm sorry about the VIN I just forgot about it, but my VIN is WDD2122821A574817
Yes I was talking about the K67 relay, it's located in the rear on the left side, next to the rear light.
Unfortunately no, I didn't test it under load with the relay plugged in. I did retest it with the relay inserted and measured
0v on pin30
14v on pin 86
Pin 87 had good ground, around 4 ohms
Fuse 68 had 14v
I kinda lost you there, i think.
There are no #160 or #162 fuses, to my knowledge. Fuse #32 which was 40a I believe, was ok, and I believe all the fuses in the front SAM (drivers side under the hood) and rear SAM (in the trunk behind the cover) were OK.
I didn't check this since I had the 14v at fuse 68, and at 86 on the relay.
I haven't tried jumping it as i didn't have the 30-40A fuse and the wire.
But I have a brand new compressor now, I wanted to replace it 1,5 year ago any way, had a good excuse now. But since I dont have the voltage in pin 30 I cant run it.
So my current problem seems to be the #30 pin on the relay/plug.
​​​​​​​Any advice?

 

No just the rear, no air at the front.
I have a dashcam and no one came near my car during the parked time.
Besides if the air lines had been cut then the compressor should turn on, but it doesn't, at all.

 

Attached F32 Prefuse box in PDF

Below is the visual of F32




Sorry, I typed wrong when I wrote : You also need to check if pin 87 of relay K67 gets proper ground or not. Pin 87 to car clean unpainted metal, using resistance/ohms. What is the reading.
I actually meant Pin 1 of Air Compressor, which is negative feed , to ground lug W6/4. But it is okey, you have Ohm it via the motor winding ....hence you get 4 Ohms and not near zero Ohms.

Your wrote :
Pin 87 had good ground, around 4 ohms
Below is how you measured and got 4 ohms. Its is okey, most important is the air compressor does not loose its ground connection to W6/4.






See the F32 prefuse box is the power source of the air compressor Relay K67



The fuses inside F32 is not replaceable. I meant MB does not sell the fuse stand alone.
This is inside and F32, yours will be similar but probably not 100% the same. There are a few types and also depending on car models, say C Class or E Class.




You wrote : 0v on pin30
I hope it is not the fuse blown but only bad wiring splice ( parallel joint ).








Read the F32 PDF I attached . As per your VIN, your car is a B03 Start Stop.
So the Pin 3 is where the Fuse 162 for Airmatic K67 relay power supply is from.




.........








On my F32 Prefuse box, which is supposedly the same as yours, pin 3, 2 and 1 uses a single big connector you can pull out. Not using hex nut.like other bigger wires.
So you can test pin 3 for +12V








No wire for Pin 3 on mine, as I do not have Airmatic
.




My car is Right Hand Drive




Okey, have fun troubleshooting.

 

Damn man, thanks alot, your posts contain alot of information and teaching.
I went straight for the F32 and measured the 3rd pin, low and behold, I got no measurement, it's blown.
so now starts the hunt for the fuse or used F32 box.
But I find it strange that the 60A fuse broke but the 40A relay didn't, and didn't protect the 60A fuse either, if I'm understanding this correctly, then the compressor line from F32 only has the 60A fuse and the 40A relay, and no other fuses?

Thank you so much for all the help.

 

Ouch, the F32 fuse 162 blown.....
Yes, specific to the air compressor A9/1 , it is protected by 60A fuse and operated by that 40A relay. You must have seen the relay label as 40A rated, because the wiring diagram does not state relay capacity.
Relay does not protect, it is basically only a high power switch which can be commanded by a low power signal.

Well fuse are thermal, they are always bigger than necessary as the engine bay is hot and exceeding 25Celsius, there is capacity drop per 1 celcius rise.
Air compressor at best if normal and healthy will consume 25 amps there about, hence 40Amp relay is good enough.
A fuse that big can only blow if the air compressor is really shorted at its winding or the wire from F32 all the way to the K67 may have touch ground/body/metal. Meaning wire is wounded.

Before you blow any more fuse, assuming you can buy the fuse , first test the 6mm red wire from F32 to the relay K67 pin 30.
Measure if pin 30 at Relay K67 big 6 mm red wire is shorted to ground or not, ohm the wire to a clean bare metal or the negative post of the start stop baby 12Ah hr at the trunk, that is a clean good ground.

If wire is good no short to ground, you then need to use spare battery somehow ( or start stop 12Ah battery or a 30 amps 12V DC power supply and test the air compressor with it,
while using 2 of 30 amps common ATO fuse our car is using, which is easier to buy than the big 40Amps up fuse.
This fuse housing is a good one for test purpose or for actual use :
If indeed air compressor is bad, replace also the K67 relay when you do replace the air compressor.
The contact points of the K67 relay I can guarantee you would by now be no more good and it may become a next problem and intermittent one....which is a PITA .

For best data collection. Test your compressor pin 1 and 2 to its metal chassis ( scrape the paint ). There should be no connection.
If it has some low resistance, that means the coil winding coating has failed and touched the compressor metal body, that is also a short circuit condition.
Coil winding is not insulated by pvc or rubber like a wire, its like enamel paint...very thin coating.




Happy troubleshooting...........

 

No I don't think the 40A was written on the relay, just saw it somewhere online.
I tested the wire and it wasn't shorted, atleast not when I tested it, but who knows what will happen if I start driving the car again, maybe there's a break in the wire that gets exposed when the car starts moving again.
I have already replaced the compressor now, as it was already due. I couldn't get a new relay and a new filter unfortunately from where I got the compressor, I'll have to get it on Tuesday, is there any danger of running the old relay with the new compressor?
I haven't found the fuse or the F32 box yet, and I didn't want to make any "redneck" fixes to it. I had noticed earlier that the pin#2 50A was unused, so I just moved the pin#3 into pin#2 slot and got it all working again, should be able to run it like that until I get back home or find a fuse/F32 on Tuesday, right?

I also noticed that the F32 box wasn't stamped with the mercedes star or part number, but there was a white sticker on back that was unreadable, shouldn't there be partnumber stamped on the box, or is it maybe aftermarket?
But the little box inside it (Fuse Box Relay Module Regulator) was marked with the star logo and partnumber.

 

Aha...so your pin 2 is empty of use, because it is only for RHD car. Sweet. It is 50 amps, yes you can use it.
As to not renewing your K67 relay, if you are lucky that it is still decent, it will then work. Bad relay wont damage the air compressor if you don't use it too long. It will give lower voltage or none at all.
If you want to know relay K67 electrical condition, you can do a voltage drop test on it, while air compressor is running.

Use DC VOLT setting on your DMM, prefer low setting like 10V maximum, if yours is auto ranging, its cool.
Sense the pin 87 and 30 with the DMM at VOLT setting while air compressor is pumping, the value you read is then the Voltage Drop, maybe 1V or less.
If relay is healthy, voltage drop would be less than 0.5 volts loaded.

You wrote :
I also noticed that the F32 box wasn't stamped with the mercedes star or part number, but there was a white sticker on back that was unreadable, shouldn't there be partnumber stamped on the box, or is it maybe aftermarket?
I cant comment on that, but sometime P/N stamping could be sticker based.

You wrote :
But the little box inside it (Fuse Box Relay Module Regulator) was marked with the star logo and partnumber.
I guess your F32 is not aftermarket unit.


Voltage drop test on relay pin 87 and 30. This is the baby sized relay found on Front SAM and Rear SAM. Some of these have TSB, they give intermittent problem. You best check yours too.


2 of 50 watts lights and 3 of 50 watts lights as load.
Voltage drop at 100 watts ( +- 8 amps ) load is 0.09 volts rounded. At 150 watts (+- 12 amps ) it is 0.13 volts rounded. This is a 20 amps rated relay if I recall correctly.

The mini relay TSB : https://www.tsbsearch.com/Mercedes-B...54-15-P-057373
Courtesy of Cali


Safe drive.......

 

The "fun" never stops...

The airmatic has been working great until just now.
I came to the hotel, ate dinner and went out for a fresh air when I noticed the car had fallen down again.... I really wanted to start crying... car acting up again, the night before going back home.
I just couldn't belive it, so I went to the car and started it up, saw the rising warning...
I was really relieved hearing the pump coming on, the car raised up just fine, then I turned it off and I could hear the air and see it lowering down to the street again.

I was just to exhausted to check it out again.
I did how ever put the cover for the compressor back under just before the ride to the hotel, I never put it back when I replaced the compressor due to time constraints, cant believe that's the problem, but all signs point to it. I also have replaced the relay.
But what on earth could it be if not because of the cover?
I didn't think about until I was back in the hotel room, that maybe I should have double checked if the compressor turned off after reaching it's designated height, I thought I had heard it turn off, but can't be sure.
But the strange part is, after I had placed the cover, the car staid up, and was still up when I came to it again 40 minutes later.

Any one have any other ideas on what could be the problem?

 

The plastic protection cover has nothing to do with what is going on

What probably happen is this :

The old compressor before it went bad, had been producing wet air, because its desiccant pack is already wet.
Desiccant is NOT the intake filter, this is those white small ***** which its duty is to capture water moisture and is packed inside the compressor.
Here : https://mbworld.org/forums/e-class-w...e-rebuild.html

This red color is super wet desiccant



I am also using such desiccant for my dive compressor air treatment cartridge. Mine is called 13X, which is a molecular sieve size designation.
This is a dry one but have expired. In a dive compressor application, our air is crazy dry at 0.005% humidity or -50 Celsius or -58F dew point temperature.
If air is wet, fire fighter in winter can freeze his air supply regulator and diver too = no air to breath.
Since diver or fire fighter uses minimum 200 BAR air supply and brought down by the 1st stage regulator to 10 BAR and then by 2nd stage unit to human breathable a bit over ambient pressure,
the 200 BAR to 10 BAR pressure reduction has approx -30C / -22F cooling effect on the orifice and the seat.

ABOVE : This is an expired desiccant. I replace them when they are still able to dry air to at least -42 Celcius dew point. Which is crazy dry under 0.1% humidity.
My country is tropical, so we do not need -50 Celcius dry air for diving, there is no ice diving.


This is a wet one, when my staff forgot to dump condensate from the water separator till1-2 hours later. It has to be done every 10 minutes.




The problem with desiccant is, when it is too wet, it will form this whitish powder



This powdery stuff is what choked/contaminate the valves of the airmatic system and can give a real leak or intermittent leak.
Of course by now your airmatic air lines are also very wet with water droplets from water moisture.


--------------------------

So what you are probably experiencing now is the whitish-residue-dirt is moving around along with air-pressure from your air compressor to the air distribution block aka Y36/6 AIRMATIC VALVE UNIT
https://www.ebay.com/itm/265237319217




There are 10 air valves as per the schematic.
Y1 at air compressor
Y1 to Y5 at air distibution block Y36/6 AIRMATIC VALVE UNIT
4 units, 1 each at air dampers Y51 to Y54





.





All airmatic on today's car , probably all brands, are crude design without water separator. They rely solely on desiccant only as air drier facility.
I know water separator is not small size...., but complete airmatic pneumatic system in a W212 is not cheap.
Rule no 1 when using compressed air is CLEANLINESS and AIR DRYNESS.

The reason for wet air in compressed air is simple.
Let say your ambient air is 50% humidity at 1 ATM. 1 ATM is very close to 1 BAR, so we use BAR instead for easier reference.
Lets use 5 BAR minimum air pressure for airmatic operation.
So 5 BAR air pressure will make the 50% humidity air becomes more than 100% humidity because it is like a 5 liter of air get squeezed to fit a 1 liter space,
hence the water moisture from the compressed air will have to become liquid water...it is physics.
That is how we get water from the air. Compressed it and cool it down. Cooling down or air pressure reduction.

Airmatic system supposedly dumps air thru its desiccant pack to also dry it, but it is not that simple. You need high heat to dry desiccant.

So, as the car gets older and a few thousands liters of air been pumped by the 1st compressor, by the time the desiccant pack in the air compressor
already saturated, it then becomes wet and no more adsorbing water moisture ..... you then get a "wet" air.
Overtime the whitish residue will then form and bits of it get pushed all over the pneumatic circuit of the airmatic, also water get pushed.
So all the 10 valves I mentioned will get fouling and it is a matter of time when one or more will partially open or closed only.
If partially close and cant fully close, is the failure we do not want, as that is a leak condition.


Take your time and clean and inspect first the : Y1 to Y5 at air distibution block Y36/6 AIRMATIC VALVE UNIT

Here is a video on it :

Press the YOUTUBE LINK on the image. It will get you to Youtube.





Enjoy the work.............

 

God damn man, a lot of info there I dididnt know, thank you so much!
But you were partially correct, the cover for the compressor wasn't the culprit, nor were the valves, there was a hole on the left airbag, it could have come when it collapsed.
I've replaced the airbag and everything seems to be working now, and I should be able to go back home tomorrow.
Then i should be to go over the valves as you mentioned and replace the right airbag.

Thank you so much again!

 

Age starting to eat the rubber material of airbag..... it is given..

 

The sad part is that they were only 3 or 4 years old, I was told.
They weren't authentic MB ones, but you would expect them to survive longer then that.
But i managed to get back home, so I'll have better workplace to change the right one, and maybe get new air lines also, I noticed that they weren't original and were alittle bit too short and soft.

 

No aftermarket ones will last as long as MB genuine one, that is what I gather from all the repairs I seen on the internet.
10 years is approx the typical lifetime for airmatic dampers + bags in my tropical country.
My friend has a W221 of 2008 and it already has complete set of 4 replaced

 

Yea true, I didn't expect them to last as long as the original ones, but atleast 5 years, but I live in Iceland so I guess that ain't helping.
I just wished they didn't have to be so damn expensive lol, they are around 1000 to 1200usd per piece here for the originals. I know the dealerships have higher prices then others, but there's a limit for everything, just lucky that i love working on my car, otherwise I would go broke lol.
Thankfully there are alot of resources on the net and the wis/asra/xentry, and ofc people like you that take their time to help others in need, wich I greatly appreciate!

 

Ouccchhh Iceland is so cold.... me will shrink me ba-lls there.
You guys are among the Skid Control King of Europe for a driver.

My friend asked me to go to Iceland last year with him and his wive to drive a rental car, he likes driving ...me too.
So me 2nd driver, its about 1,200KM ish trip on a Toyota 4WD.

He said -20C, I said go hell !!!!

He is a 1980s Porsche 911 widow maker capable driver, but not for ice, for tarmac.
So he said, he was the SLOWEST driver on the road in Iceland with such snow, even truck is faster than him....LOL.
I told him, them Nordic countries, their drivers are the WORLD BEST RALLY driver.....so we all seems slow in the thick snow.


Okey, get yourself ebay EPC/WIS if you do not yet have it... it is a must and a decent scanner, Launch for MB specific is under US$165 and it can do a lot. We call this version 1.0
There is a version 2.0 too, can do BMW and MB, maybe Audi too...I don't follow its progress now.
I have the version 1.0 baby Launch and other scanners, but I love my Xentry BenzNinja version the BEST !!!!

 

Haha its not always -20°c here, last winter was pretty hot here, usually stayed around 0 to -8°c. But there are places here that can go longway to -30°c, lowest heat was -38°c in 1918 😅And yes you can see who are tourists in the winter time, as they usually drive around 40-60kmh in a 90kmh zone, and even low as 20 if its snowing or blowing snow, they are usually out of view after couple of seconds after I've passed them 😂
I just love how the s212 is "glued" to the road, even in the winter time with snow and ice on the road.

I have the iCarsoft CR MAX and a V2024.3 SUPER MB PRO M6+ which has xentry, das, EPC, WIS, starfinder and other things.
I really liked the iCarsoft, but ofcourse it has its limitations, like, not showing default values and doesn't have complete access to the car computer.
The M6 is pretty good and seemed to work just as the authentic Mercedes Xentry, havent had much time to work on it and trying it out, but will soon.

 

You could go aftermarket for the air bags. I installed Arnott air bags on my 2011 S212 about a 1 1/2 years ago and am quite pleased with them. My original bags started to leak around 109k miles on the left rear and I decided to replace both because I knew it was just a matter of time that the right side would start to leak also. Only problem I had was unseating the base of the air bags because it was rust seized on the bottom where it fits into the control arm. Do yourself a favor and soak this area with rust penetrant a couple of days before you start the repair and have a small sledge hammer ready if it offers resistance. Also after removing the old bags make sure the cavity where the bottom of the air bag sits is clear of as much rust as possible and coat this entire area with grease to prevent rust seizure on the replacement air bags.

 

I've been seeing alot of Arnott lately, I might look into that next time.
Yeah the left one was really stuck, I had a repairman from the dealership changing it and it took him quite a while to remove it, it was like it was glued down with rust and fine dust.