Hello! Not sure if this is the correct part of the forum to post.
I have a 2011 S212 E220 estate, RHD.

Over the past 2 years, as with others, I have had a problem with the rear air suspension. It’s not the full 4 corner airmatic, just bags on the rear as it is an estate. Overnight the car would sink down, and when I started it the next morning it would rise up. Eventually the car just stopped rising up. Therefore it sat on the driveway for a good few weeks until one day, when I happened to turn it on, it rose up! And worked for about 2 months straight (sinking overnight, rising when used).

At the start of this year it finally stopped rising altogether, myself and mechanic came to the conclusion that the compressor wore itself out as it was constantly having to turn on to keep the car rising up. I bought aftermarket bags and compressor and got it fitted. Perfect, car was nice and high as normal, didn’t drop down at all overnight. That lasted for a week. Suddenly the same problem, dropped down fully and wouldn’t budge, still getting a ‘vehicle rising please wait’ message, but no movement.

Now I know there are ride height sensors on the left and right, just next to the bags, but my question is, is there a centre sensor? I ask this as a guy I know had the same problem and said there is an additional sensor in the middle rear of the car, underneath a heat shield. I didn’t know this, and apparently neither did mechanics. So much so, he rang the local dealership asking for the central sensor. The said ‘there isn’t a central sensor’. He then apparently read out the part number and they were then like ‘oh…. I think you’re right, there is’.

Has anyone seen or personally dealt with this supposed central sensor? Before I ask my mechanic to spend his time (and my money) searching around for it? No ramp myself at home to have a look, and I don’t trust my 2t car on Jack stands! Any other help or advice on the issue would be appreciated. Tempted to change to coils if it goes unfixed.

Thanks all, I appreciate the help. If this is in the incorrect section please let me know where it would be better posted for an answer!

Welcome.

This is an old car. If it were mine I would replace the rear leveling system: bags, sensors and compressor.

moved to W212 forum...

Exactly, 10 year is due for the major ovehauling of the suspension components

I did have wagon (estate) W211 and it did have only single leveling sensor.
Bad compressor will not drop the suspension overnight, but sounds like you put it in high overtime, so you will need it rebuild or replaced anyway, but YOU'VE GOTTA LEAK.
You might find option on the scanner for activating the compressor and go under with spray bottle and soapy water in it, to find if you might have leak on the lines. The bags are harder to troubleshoot as they have covers, but generally, if the bags are 10 years old, you should replace them.
Good luck.