AaronF

Hello all, this is my first post to this forum, so please bear with me if I sound like a bit of a newb, because I sort of am . Just recently, I purchased a 2013 GL63 AMG from a dealership down in Florida (I am in New York). Everything with the vehicle was good down in Florida, but upon delivery to New York, the dreaded suspension malfunction graphic popped up on the dash on first start.

Symptom:

• Left front shock will not fill with air when being raised, and I get a suspension malfunction error on the dash. LF suspension will raise a few mm, but that's it.

A bit of history:

• The suspension was just serviced by a MB dealer about a month ago, and the 2 front air shocks were replaced. This was done just before the vehicle was traded in, and I have receipts proving the work was done.
• I have a iCarsoft MB II scanner, so I can clear codes and check suspension levels, but it's not a bidirectional scanner, so cannot do any specific tests.

Notes on what i see:

• The suspension seems to hold air over a couple days minimum. I haven't had the vehicle long enough to let it sit longer. That, and I keep playing with the system trying to uncover what's going on with it.
• The scanner reports a C155664 error - "the compressed air sensor for the system has a malfunction, there is an implausible signal"
• At it's low point, after clearing codes, when I press the suspension button to raise it, the vehicle mostly raises, but the left front shock only goes up a few mm.
• Here are the suspension levels at low point, and raised (at the point where the error pops and the vehicle stops raising):
  • Lowered: LF -22, RF -21, LR -15, RR -19
  • Raised: LF -16, RF 2, LR 7, RR 13
• Once raised, if I clear codes and try to lower the vehicle, it will not lower, even though the "lowering" graphic pops up on the screen. It's not until I turn off the vehicle and close/lock the door, that the suspension quickly drops.

Here's what I have done so far:

• Clear codes (error comes right back when attempting to lift the vehicle
• Soapy water tested the top of the left front shock to check for leaks. Did not test the bag, but again, they are brand new and I don't believe the vehicle doesn't losing air.
• Loosened the line going into the shock and air started hissing out, so air pressure is present. The scanner reports this too.
• Loosened the same line going into the distribution block/valve, and air started hissing out.

So I have 2 questions:

• How should I go about further testing to see what's going on, without throwing parts at the problem? Or is it obvious what the problem is?
• Can someone recommend a good quality bidirectional scan tool that will test the individual suspension components like the Mercedes STAR tool can? I don't know that I am comfortable using a knockoff that could be rendered useless at any point. It looks like Autel makes decent units, but I cannot tell what models will support specifically what I am trying to test for.

Thanks in advance for your help!

AaronF

So I have my bidirectional scan tool question answered. I am going with the Autel MS906BT. I confirmed it will work with the suspension in the GL63.

If anyone can help with my main question, that would be awesome.

Thanks.

AaronF

I received my Autel MS906BT scanner today, and started running some tests on the suspension. After draining the air shocks, I disconnected the air lines going into the 2 front struts, and found that no air is being pumped to the left front strut. The line does not seem to be kinked, so I have a feeling it's going to be a bad distribution block. Will find out tomorrow.

serb

My 450 squats at the rear when i dont press raise vehicle button,if i do i stays normal height when you turn off the engine,what is usual labor to replace 2 rear air shocks?
got a quote for 950$ With parts i think thats too much

mtm

You can do it yourself in less than an hour. Rear air bags from Arnott are inexpensive and good quality:

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

The replacement process is easy:

M Ridwan Zamrik

Hi all, mine is costing me a fortune on suspension. 9 months ago FR air suspension burst. 3 months later FL burst. Then had to change full shock absorber, stabilizer, arms, rods and all. Being a heavy car seem to wear suspensions very frequently .
quite anxious to drive comfortably but recently air pump got busted
so disapointed

AaronF

I hear you. Are you doing the work yourself? Almost seems to be a must, unless you are ok with spending a crazy amount of $$ on labor every time it needs work.

serb

I dont have a garage,live in a condo so im gonna have to put it in a shop

mrtoofay

For the rear airbags, you don't need much. Just a level surface, jack and jackstands, some simple handtools and a piece of cardboard for when you lay on the ground to access the air hose nut. First one takes some figuring out, second one takes less than 10min. Jacking the car up and putting it on jackstands takes more time. You can do this on the side of the street if need be. Remember to chock your front wheels when jacking up the rear. The arnott rear bags should cost less than $300 for both.

serb

What about bilsteins are they good?

serb

just ordered 2 new oem springs from ebay 212$ shipped,good deal?

mrtoofay

Don't know about others. I find Arnott to be better quality than oem.

serb

Just fixed it today,200$ labor to replace both rears,i can not hear compressor working hard most of the time like with old ones so i am happy but looks like i will need new radiator