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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 54019
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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Marty! I have a 2006 R350 with the rear suspension all the

Customer Question

Hello Marty! I have a 2006 R350 with the rear suspension all the way down. It rides very hard.
Submitted: 2 years ago.
Category: Mercedes
Expert:  Marty replied 2 years ago.

Hi, did you also replace the compressor fuse?

Customer: replied 2 years ago.
I replaced the 40A fuse
Customer: replied 2 years ago.
it checked out ok and I replaced it anyway
Expert:  Marty replied 2 years ago.

Ok, if you bypass the relay will the compressor turn on?

Customer: replied 2 years ago.
Expert:  Marty replied 2 years ago.

Ok, but the compressor will not turn on when you start the car or when you press the button to raise the car, is that correct?

Customer: replied 2 years ago.
press the button to raise the car? Were is that located? I can't find one on the center console
Expert:  Marty replied 2 years ago.

If you only have rear air suspension there will not be a switch on the dash.

Expert:  Marty replied 2 years ago.

On all wheel air suspension the switch is next to the hazard switch.

Customer: replied 2 years ago.
what does it look like? just to be sure...
Expert:  Marty replied 2 years ago.

Click on the link below.

Expert:  Marty replied 2 years ago.

If the compressor will not turn on you will need to get the car connected to any Mercedes scan tool that can read and erase fault codes in the Airmatic control unit. Once the fault codes are erased the compressor will turn on.

Customer: replied 2 years ago.
I don't have that switch. I do have a scantool and have cleared the faults, but it still doesn't come on.
Customer: replied 2 years ago.
is there something special about the Mercedes tool that is different to my scan tool?
Expert:  Marty replied 2 years ago.

Did you go into the Airmatic module and erase the codes or did you only erase the codes in the engine control module?

Expert:  Marty replied 2 years ago.

If your scan tool cannot select the Airmatic module it cannot erase the codes.

Customer: replied 2 years ago.
in my scantool tool, it is under "air suspension". There is not any codes listed there...
Expert:  Marty replied 2 years ago.

What brand is the scan tool?

Customer: replied 2 years ago.
iCarsoft is the make of the scantool
Expert:  Marty replied 2 years ago.

I'm not familiar with that tool. As long as there is power to the relay and the compressor runs when you bypass the relay this should just be a matter of erasing the codes with a Mercedes scan tool. I am assuming that the level sensors at the rear are connected. Also make sure fuse 32 and 53 in the rear fuse box are good.

Customer: replied 2 years ago.
Also, one level sensor was broke which I replaced. Do you have a picture of were fuse 32 and 53 are? I will check right now
Customer: replied 2 years ago.
fuses 32 and 53 are ok in the rear fuse box
Customer: replied 2 years ago.
do you recommend a Mercedes scantool that will work? or do I have to go to the dealer?
Customer: replied 2 years ago.
is there a trouble tree / diagnostic tree for this system?
Expert:  Marty replied 2 years ago.

I'd go to the dealer or to an independent who has the Mercedes SDS or an equivalent factory level tool.

Expert:  Marty replied 2 years ago.

We've basically gone through the trouble tree. Power to the relay, power to the control unit, compressor runs when bypassed. All that points to no activation by the Airmatic control module.

Expert:  Marty replied 2 years ago.

With the factory scan tool you can activate the compressor to test the entire circuit.

Customer: replied 2 years ago.
ok, I will check the dealer tomorrow. I just don't like going to the dealer!
Expert:  Marty replied 2 years ago.

I understand. What usually happens is when the air bags fail it causes the compressor to run excessively. The Airmatic control unit will turn off the compressor and set a fault code when that happens. The compressor will not start again until the codes are erased.

Expert:  Marty replied 2 years ago.

Also make sure that your level sensors are connected properly.