Mercedes-Benz W211 air suspension: rear stays down or the car leans
W211 air suspension: why does the rear stay down with no fault message?
The rear level sensor's lever is attached to the rear anti-roll bar link. If the link comes off, the sensor arm drops down and the car thinks the rear is too high, so it does not fill the springs with air. The cause can also be a weak compressor, for example a cracked air intake pipe.
How are the air suspension compressor and air supply checked?
A healthy compressor raises the rear in under a minute. The air filter and the air dryer may be blocked, so they should be checked first. The compressor should not start if the level sensor shows that the rear is at the right height.
Why does an Airmatic car lean to one side?
The rear has only one level sensor, so a single side cannot be levelled separately. Common causes are poor contact in the connectors, where cleaning often helps, and worn control arms and lower ball joints. Replacing the height sensor does not always help. Front adjustment and calibration are done with workshop diagnostics.