How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Lou P. master tech Your Own Question
Lou P. master tech
Lou P. master tech, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3724
Experience:  15 years master certified 100% fix rate and have access to factory radio codes, wiring, and instructions.
27644750
Type Your Mercedes Question Here...
Lou P. master tech is online now
A new question is answered every 9 seconds

I have a 2012 CLS550 Base. I'm having an issue with my

Customer Question

I have a 2012 CLS550 Base. I'm having an issue with my Airmatic all of the sudden. I noticed the rear of the car was not coming up to ride height one day so I of course checked all fuses and relays as well as just replaced the Airmatic relay with a newer model. The car has no engine lights on and has no Suspesion codes all is normal in that regard. I hot wired (Jumped relay) and the compressor comes on as normal but does not raise the vehicle. I've jacked the car up now that it is much lower, checked all fittings, hoses, plunger/actuator and wiring. I am at a stand still as the sytem was working perfect and I've had no lights or warnings etc. Dislocated the battery a couple times and steered stop to stop to reset. Battery has sufficient voltage. What am I missing here?? Thank you
Submitted: 3 months ago.
Category: Mercedes
Expert:  Lou P. master tech replied 3 months ago.

Hello, its possible the valve block is the issue , there was some problems with those.

do you have a mercedes scan tool that can read and actuate the airmatic system?

jumping the relay will do nothing but activate the compressor , it will not allow air to the struts as the valve block has solenoids inside to prevent air to pass.

what is your vin and how many miles do you have on the car?

does the rear attempt to raise at all when first started?

does the compressor sound loud and noisy or a slight hum?

i will not be on much longer tonight but i will be back in the am so feel free to reply as many times as needed. Lou P

Expert:  Lou P. master tech replied 3 months ago.

there was also a bulletin for this issue as well stating to spray the valve block down with leak detection spray (soap and water lol) and see if bubbles occur. i will attach the bulletin as well as the pictures which leave something to be desired.

Customer: replied 3 months ago.
A buddy came over to scan with a DAS and was unable to activate it but yet had no codes. I insoected the Valve block disconnected the plug and cleaned etc. It keeps making a Noise as it has for awhile when you get out of the car like its purging air. Its done this until now wheels are all the way in the wheel well.
Theres 82k on the car. Havent had any other issues. No theres no activity from the compressor at all anymore.
Compressor sounds like it has a moderate hum same noise
Expert:  Lou P. master tech replied 3 months ago.

here is the bulletin so you have it. it can still be viable even though the car has some age and miles on it

Expert:  Lou P. master tech replied 3 months ago.

ok , with the das can you activate the compressor?

if not then you need to check for power and ground at the compressor when activating regardless of having it jumped like you did before

also what does the rear level sensor show for height?

you should be able to adjust or activate the compressor to raise the rear bags. if not then the valve block can still be an issue, the system is dumb and will not always code up. that is the tricky part. so we need to systematically try things to narrow down what is happening. i do these all the time on here lol 99.9999 success rate :)

we can get this figured. when can you have the das back in action?

Customer: replied 3 months ago.
Maybe tomorrow afternoon but the compressor wont come on regardless. The rears said like 6mm or something like that. would it have anything to do with the accelerator sensors? I also have lowering links on the car but inspected and they are normal just way past their limit no bc its so low. Do I need to jack it up so it doesnt start from ground level to reset or something?
Customer: replied 3 months ago.
Where should I check for power at the compressor?
Expert:  Lou P. master tech replied 3 months ago.

wait, you installed lowering links?

did you also do that in the rear?

you will check for power at the big fat red wire on the compressor, also make sure the connections are not burnt at the compressor. i thought you said you jumped the relay and the compressor came on?

Customer: replied 3 months ago.
front and rear. Ok let me check that now. Key on engine off?
Customer: replied 3 months ago.
lowering links have been on about a year no issues
Customer: replied 3 months ago.
compressor runs with it jumped
Expert:  Lou P. master tech replied 3 months ago.

ok, so we know the circuit is good then for the compressor.

Expert:  Lou P. master tech replied 3 months ago.

we need to keep the car on the ground.

Customer: replied 3 months ago.
ok I have it on stands should I lower it?
Expert:  Lou P. master tech replied 3 months ago.

start the car and use the scanner to activate the compressor, if it does not run then we need to verify power at the compressor when the scan tool is activating it. even though it ran before its always possible the compressor is intermittently locking up.

Customer: replied 3 months ago.
ok
Expert:  Lou P. master tech replied 3 months ago.

oh god yes lol, if the wheels are hanging the car will think its in the air and not function the compressor.

Customer: replied 3 months ago.
ok on sec
Customer: replied 3 months ago.
ok car is on the ground. Theres power at the compressor as well
Expert:  Lou P. master tech replied 3 months ago.

ok so there is power at compressor but compressor is not running?

Customer: replied 3 months ago.
No the compressor runs just doesn't raise the car
Expert:  Lou P. master tech replied 3 months ago.

OK, lol, please try and be clearer in your description so we can come to a result faster, ok so get the compressor running and then spray the valve block to see if there is air coming out of the lines, if no air leaking, then remove the rear lines from the valve block and see if there is actually air coming out of them to the rear , if there is then the issue is with the pressure or the rear shocks, if there is not then we have a valve block issue.

Expert:  Lou P. master tech replied 3 months ago.

here is the valve block location

Customer: replied 3 months ago.
Ok I can do that! I'll be out for awhile I will do that when I get back. Thank you!
Expert:  Lou P. master tech replied 3 months ago.

ok no problem. please do not forget to rate my service :)

and no worries it will not end this chat, i will not leave another technician hanging lol.

Customer: replied 3 months ago.
Ok checked and no leakage at the block, air coming out of the compressor through the lines. seems like valve is blocking air and you can hear it continue to purge electronically
Expert:  Lou P. master tech replied 3 months ago.

ok, so you need to verify if the valve block is allowing air to pass by removing a few lines to the rear and front shocks, that would tell me if the valve block is the culprit, so far that is what it sounds like to me .

Please take a second and click the STARS above and rate my service 4 or 5 stars if you feel I have been helpful and please request me in the future. Keep in mind that when you rate it does not end our conversation, you can still return here to me for follow up information if needed, Thanks for choosing just answer. Also , if you feel i deserve one , BONUSES are GREATLY APPRECIATED! Thanks again , Lou P.

Customer: replied 3 months ago.
Its Obvious the block Isn't allowing air to pass. I well aware of that issue. The research I've done points to the computer not allowing air to flow to ANY of the shocks. Many factors contribute to that. That's why I asked this question. Sorry for being blunt but you havent answered anything for me that I haven't found out prior. I was charged the full amount for nothing so far. So rating you wouldnt be in your best interest at this point lol
Expert:  Lou P. master tech replied 3 months ago.

oh wow,

well your research will never match my experience and knowledge of the system. and dont say stuff like so obvious, because if it was that obvious you would not be here asking for help .

if the car is on the ground, and the level sensors are showing that the level is lower than the coded programmed level should be , and there are NO codes, and the compressor operates, then the valve block should open to allow air to pass . if the compressor does not come on and there are no codes then something is wrong with the power supply or compressor, since we verified it does come on we can rule that out. but if it does not come on by its own then the module is locking the compressor out, which means there would be a code. if no code then the scan tool is not picking up the code.

Expert:  Lou P. master tech replied 3 months ago.

you cannot have no codes and no compressor activation from the module, that is implausible, if you do have a das we can go step by step with the actual values. but its your call, at this point i am a little put off and feel that my efforts no matter how great , will still be discounted based on some forum you read. have a good night, i have to go , i will check back in the morning . if you would like me to opt out i am more than happy to do so , to see if you can get some better help. i want you fixed up whether it is me or not. however i do 99.99% of airmatic issues all day everyday with 100% success. for what that is worth. Lou P.

Customer: replied 3 months ago.
you understand why I asked for help now lol. I'm not a technician just have some common sense. As I said the compressor DOES operate on command and hot wired but not in normal operation. Circuit is in order even checked point to point with a multi-meter. Another thing I noticed is the button will change from sport to comfort and display on the dash, but when I press the raise button(or whatever its called) it doesn't say anything. Sorry didnt mean to put you out just trying to get answers. If you cant think beyond what my NON experienced/Knowledge self already has done, we might have an issue. Maybe point me to someone else with more?
Expert:  Lou P. master tech replied 3 months ago.
Ok I think you missed what I was saying but I will go ahead and opt out. You CANNOT have everything check out and not have compressor activation. That is not how it works. And I don't know what you are checking with a meter because without codes there is nothing to check. Something obvious is missing. I told you If you have a das we can go over all the values and see why it's not activating the module. It seems that you will not read my post thoroughly and that will make it that much harder to assist you. I will opt out and see if another expert can assist you as get you fixed up. Sorry it did not work out for us. Lou.
Customer: replied 3 months ago.
No Problem. Trust me I understand if I had the most up to date STAR scanner I wouldnt need your help. I checked voltage with a multi meter from the battery, to the pre-fuse, to the 40amp fuse to the relay and then the compressor. For not only voltage and drop but resistance ohms as well to see if there were any resistance issues etc. You said at the beginning "the system is dumb and will not always code up. that is the tricky part." so I thought we were on the same page. Since it wasn't an obvious issue you want to bail I guess. Can't win them all.
Expert:  Lou P. master tech replied 3 months ago.

ok in reference to that statement i meant that in a different way. it will not code up if the rear level sensor link broke and the level showed perfect in the values but the actual level was dropped to the ground, in that instance is what i meant. just to clear the air.