Hi. Im new here. Need help. Airmatic problem. Whendriving empty or with one passenger is all ok,but when two people are sitting on back seats,back of car is very low(front look normal)and "Airmatic. Stop! Car too low"message appear on dash screen. Anyone can help? What the reason can be?(pump?absorbers?valve?air leak? ) And how to solve the problem? Thanks.

 

Hi,

I see you are in London.

You shouldn't use the vehicle when this WARNING (RED) is showing!

Basically the car is too low and this can restrict available lock and there is inadequate compliance in the suspension (ability to absorb road shocks).

Reason is likely inadequate air in the system. This can be due to:

Pump failure.
Valve failure.
Sensor failure.
Significant leak from system.

System is usually VERY reliable but at high mileage (lets say 100k miles+) things can become troublesome...and potentially VERY expensive.

All depends how DIY / competent you are.

Best course of action is to get your friendly MB dealer to run an SDS Quick Check which will advise any DTC's (Diagnostic Trouble Codes) that have been set. This should point us in the right direction. You should get a PRINTED report showing the status of all vehicle systems. If the car is several years old you may be horrified by how many codes have been set and stored!!
If you have any "goodwill" with the dealer they may do this Free of Charge but usually charge £25 (maybe more in London).
Unless you have deep pockets I would suggest you get that info first.

The pump is located under the RH frond wheelarch. It makes (should) a noise when running. If there is no noise then no air pressure. A new pump is circa £250 + fitting but there are many reasons why the pump may not be running. Fuse / Circuit issues / sensor values / worn out etc.

If the pump is running the valve block can sometimes fail to deliver the correct pressure to one, or several, of the corners of the car and your observation front OK, rear low may fit here.

In the States leaks are quite common on the large engined variants operating with high under bonnet temps (London traffic?). This causes cracking of the seal at the top of the struts. A kit is available in the USA to fix this (non MB I suspect) but new struts are mega expensive. The crack (if present) is clearly visible around the top of the strut adjacent to where the air tube enters.

I could go on but the first step is the codes and an indication from MB (if they are prepared to do so) of what they think is wrong and the likely cost)

I experienced a fault on my S Class (which somebody else also encountered on this site) whereby the salt on our roads had corroded a wire splice WITHIN the harness adjacent to the pump and this gave INTERMITTENT "Too Low" warnings" and "Stop do not Drive" messages over several years but usually cleared after a restart or two. It was when it didn't clear that i had to determine the cause. My MB garage were intrigued by this issue because they were confident that it was the pump.
They actually fixed the problem for a mere £70 after spending 8 hours!! on the car with me present because I "bet" them that it wasn't the pump. (I had already satisfied myself that everything in the system was OK and had run out of ideas. I hadn't even considered a broken wire within the harness! I took it to them because I needed to codes..I don't have the required equipment to read suspension codes... to help me move forward)
SDS indicated "Pump failure" because the pressure sensing signal which is generated by a sensor mounted on the pump was not being seen by the computer. It wasn't being seen due to the break in the wire!

Get the codes and come back.

To read the codes takes about 15 mins (hence the £25)

Stuart

 

Hi. Went to MB dealer (Stradford) just to hear they have no time for "waiting job",and be informed that cost of checking the airmatic system is two labour hours( £99 +VAT per hour). I have checked air pump area by my self in half an hour andIhavefound air leak from air hose connecting pump and valve block. Going tomorrow to dealer,to buy replacement ofleaking hose and I'll replace it.Hope after that everything will be ok.

SNANCEKI-many thanks for Your advice!

 

£100/hr + VAT is about standardm in the UK for MB.
However to plug the computer in and press "Start" takes about 15mins not 2 hrs!!
To then actually go thru the full diagnostic procedure may take 2 hours.

Since you accessed the pump with no apparent difficulty it appears that you have grasped the issue with both hands.
EXACTLY where is the nylon pipe damaged?
I wonder what caused it to become damaged?
Accident damage to front RHS?
Would be interested in response just to expand my knowledge.

Good luck.
If you have found a leak I'm sure that will be the problem.

Stuart.

 

Problem solved! I have changed nylon pipe-2203270145 (£5.20)and now it's all ok. Airmatic is working properly,no problem with raising the car even with 5 good sized people in It seems to me,previous owner could have damaged the pipe purposely (insurance purposes?car bought as cat.C.damage to n/s doors)as pipe was cut in the middle,there was small whole done by something sharp.

Finally everything is working and car is ready for test trip to Poland and back (over 4000 km).

Thanks Stuart.
All the best!

Grzegorz.

 

luck you reighton,

mine is not so good often to replace the whole suspension when everytime i fix it which are costly over here in asia esp in brunei...

well im happy to hear u get to solve ure airmatic problem