Mercedes AIRMATIC Problems Explained

Symptoms, the parts behind them, and the tests that tell them apart. Most AIRMATIC repairs are one component. The expensive mistake is replacing the wrong one.

By the technicians at German Performance · September 15, 2026

AIRMATIC is Mercedes-Benz's air suspension: a rubber air spring at each corner in place of a steel coil, a compressor to fill them, and a control module that keeps the car level and adjusts the damping. It rides beautifully when it works, and it is the most common suspension complaint that comes to us for Mercedes repair in Snellville. It is also the system where a wrong diagnosis costs the most, because the parts are not cheap and there are several of them. This guide explains the symptoms, which component each one points at, how we isolate it with XENTRY and a few simple tests, and when a conversion to steel springs is worth discussing.

Which cars have it

AIRMATIC came in on the W220 S-Class in the late 1990s and spread across the range: the S-Class and CLS, the E-Class (standard at the rear on the wagons, optional elsewhere), the ML, GL, GLE and GLS, the R-Class, and later the C-Class and others as an option. The GL and GLS have had it as standard equipment, which is why so many of the cases we see are those. Not every Mercedes-Benz that rides on air is AIRMATIC: the S-Class, CL and SL of the same years could be ordered with Active Body Control, ABC, which is a hydraulic system with its own pump, accumulators and struts, and a different set of faults. If your car has ABC, the tests below do not apply and we diagnose it separately.

The symptoms, and what each one points at

One corner is low in the morning and rises when you drive

The most common complaint and the most misread. A car that can be lifted is a car with a working compressor and a leak. The leak is almost always the air spring itself, usually at the fold where the rubber bellows rolls over the piston, and occasionally a line or a fitting at the valve block. The corner that drops is the one leaking. The compressor is running every morning to make up for it, and if the leak is left long enough the compressor will eventually fail from overwork, which is how the two get confused.

The whole car is low and will not rise

Now the compressor is the suspect, or its relay, which fails more often than the compressor and is a fraction of the job. A compressor that runs but cannot build pressure has worn its piston ring; one that does not run at all usually has a relay or a fuse first. A thermal cut-out after a long run is also common: the car sits low after a drive with the compressor working hard, then rises after it cools.

The compressor runs for a long time, or often

A leak somewhere, being made up for. This is the symptom to act on early, because it is the one that turns a strut replacement into a strut and compressor replacement.

"AIRMATIC: Visit Workshop" or "Vehicle too low: Stop" on the dash

The control module has seen a ride height it cannot correct, a pressure it cannot reach, or a sensor it cannot trust. The message tells you the module is unhappy; the fault memory tells you why, and the codes are specific enough to name a corner or a circuit.

Harsh, bouncy or floaty ride with normal height

The damping side of the system rather than the air side. The adaptive dampers are controlled by valves that can fail electrically, and the strut's damper can wear out the way any damper does. A strut that has lost damping but still holds air will pass every leak test.

Leaning after a wheel or suspension job

Usually a level sensor or its linkage disturbed on the way in, or the calibration not done afterwards. Cheap to fix, and worth ruling out before anything is bought.

The components

• Air springs and struts. At the front the air spring and damper are one unit, the strut; at the rear on most models the spring is a separate bellows over a conventional damper. The rubber ages with heat, ozone and mileage, and cracks at the rolling fold.
• The compressor and its relay. A small piston pump with a dryer; the relay switches it, and fails first.
• The valve block. Distributes air to each corner and holds it there; its O-rings and solenoids can leak or stick.
• Level sensors. One per corner (or per axle on some cars), a small arm on a linkage that tells the module the ride height.
• The lines. Plastic, run through the underbody, and vulnerable at the fittings.
• The damping valves and the control module. Electrical, and diagnosed through XENTRY rather than with soap.

How we isolate it

Every AIRMATIC diagnosis starts the same way, whatever the owner has been told. We read the AIRMATIC module's fault memory with XENTRY, the factory software, and look at the live data: the four ride heights, the reservoir pressure, the compressor's run time and its temperature. Then we use XENTRY's actuations to raise and lower each corner individually and watch what the sensors report. A corner that will not hold its height with the valve closed has a leak downstream of the valve block, which means the spring or its line. A system that cannot reach pressure has a compressor or supply-side problem. A sensor that reads a height that does not match a tape measure is the sensor.

Only then do we go under the car. A leaking spring is confirmed with soapy water on the bellows, which bubbles at the crack; lines and fittings the same way. A compressor is tested for the pressure it can build and the time it takes. Where we suspect the valve block we isolate it from the corners and watch the reservoir. The estimate names the component the tests pointed at, shows the photographs, and says which other components were tested and passed. That last part matters: it is what stops a strut job becoming a compressor job a month later, or the other way round.

One strut, or two?

When one front strut has failed on a car of any age, the other is the same age and the same rubber, and it will follow. We recommend replacing them in pairs at the front and in pairs at the rear, for the same reason we replace brake pads by the axle, and because the labor overlaps. We do not recommend all four at once unless all four are leaking; the tests tell us which. Whatever is replaced, the ride height is calibrated in XENTRY afterwards, which is not optional: the module has to be told where level is.

Parts follow the usual tiers. The air springs in a Mercedes-Benz are made by a small number of suppliers, and a genuine or OE-supplier unit is what we fit; the aftermarket includes both remanufactured units built on the original core and cheaper new ones whose rubber does not last, and we will say which is which on the estimate.

Converting to steel springs

There are kits that replace AIRMATIC with conventional coil springs and dampers, and we are sometimes asked about them. They are cheaper than an air strut in the short run and they remove the failure mode entirely. What they also remove is what the car was designed around: the self-levelling with a load or a trailer, the ride the car is known for, the adjustable damping, and on some models a warning on the dash that has to be coded out. On a high-mileage GL that is kept as a workhorse a conversion can make sense. On an S-Class it rarely does, and it affects the car's value. We will give you an honest answer for your car rather than a general one.

Before you buy one

On a pre-purchase inspection of an AIRMATIC car we check ride height at all four corners after the car has sat, the compressor run-time counter and the module's fault memory, because none of that appears on a history report; CARFAX will show you whether the suspension was ever replaced, which is worth knowing, but not whether it is about to need it. Our pre-purchase inspection page describes the whole check. We also run the VIN against NHTSA's recall lookup, as we do on every Mercedes-Benz we see for the first time.

If your car is doing any of the things above, note when it happens (overnight, after a drive, on one corner or all four) and call. That one detail usually tells us which test to run first, and it is where every AIRMATIC Mercedes repair here starts.

Sources

• Mercedes-Benz USA: Service and warranty manuals by model year
• NHTSA: Check for recalls by VIN
• CARFAX: Vehicle history reports

Further reading

• Mercedes Service A vs Service B
• Why Mercedes Repair Costs What It Does
• Mercedes Repair Case Studies