AIRMATIC faults: car too low, compressor and leaks

Which Mercedes models are affected?

This page covers Mercedes-Benz cars and vans with AIRMATIC or air suspension. For other Mercedes work, see our Mercedes-Benz specialist page.

Mercedes workshop information on air suspension faults covers these models:

• E-Class (212) with air suspension, including the estate
• CLS (218)
• ML and GL (166)
• E-Class (213) with AIR BODY CONTROL
• S-Class (222)

The V-Class owner’s manual has an AIRMATIC section too, so we also work on V-Class air suspension where it is fitted; see our V-Class servicing page. If you are not sure whether your car has air suspension, put the registration in the enquiry form and we will check.

What are the symptoms?

• the car sits low at the rear, or at one corner, after it has been parked
• an AIRMATIC or suspension warning in the instrument cluster
• on the E-Class (213), a message that limits the car to 50 mph

When you book, tell us which corner drops, how long the car had been parked when you noticed, and which message you saw.

What causes it?

Mercedes workshop information names several causes:

• A slow leak from a rear air spring, through damaged sealing rings.
• A sticking vent valve in the compressor, which can let the car drop at one or more corners.
• Water in the system. Once water has got in, the compressor and the valve unit both have to be replaced.
• Something other than a leak. On the E-Class (213), Mercedes says the 50 mph message can come from the ride-height calibration or from tension in the rear axle.

How do you confirm the fault before fitting parts?

A fault code is not a repair, and a low car is not a diagnosis. Before we quote for any parts, we:

• measure the height from the wheel centre to the wheel arch with the car cold, leave it standing, then measure again
• spray leak detector on the valve unit, the air lines and the spring connections, and check the compressor intake line
• check the compressor and the valve unit for water
• read the fault data stored in the suspension control unit
• check the level sensors and the ride-height calibration

On the models its guidance covers, Mercedes treats a drop of less than 15 mm between the two measurements as normal. The height also moves by about 1 mm for every degree Celsius of temperature change, so we take both measurements in comparable conditions.

We then show you what we found and send a written price. No part is fitted until you give us your written approval.

What does the repair involve?

We replace the part the tests prove faulty, not the whole system.

• Air spring leak. We replace the leaking spring. If the spring on the other side of the axle is an older version, Mercedes advises replacing that one too.
• Compressor. We replace it only when the tests prove it faulty. If water is found, the compressor, the valve unit and the intake filter are replaced together.
• Ride height. After the repair we calibrate the ride height and check the wheel alignment where the job calls for it.

Once the work is done, we check that the car holds its height and verify the repair, including a road test where appropriate.

How long does an air suspension repair take?

It depends on what the tests find. The height check needs the car to stand between the two measurements, so it may need to stay with us.

Before any work starts, you get a written price and a promised time for your next update. If the car needs to stay with us, ask about a courtesy car when you book.

Is there a recall for Mercedes air suspension?

Whether a recall applies depends on the individual car, so check your registration on gov.uk. Recall work is done by the manufacturer’s network, not by us.