In this guide, you will find step-by-step instructions on how to replace the air suspension compressor on Mercedes-Benz vehicles equipped with airmatic suspension.

While the design of the air compressor varies between models, the instructions on how to change Mercedes-Benz air suspension compressor are practically the same on all models including E-Class, S-Class, CL-Class, CLK-Class, ML-Class, GL-Class, R-Class, etc.

Symptoms

• Mercedes-Benz drops on all four corners
• Airmatic Malfunction Message on Dashboard
• Airmatic Visit Workshop Message
• Fault pointing to any of the following
  • A9/1 Airmatic compressor unit
  • A9/1m1 Air compressor motor
  • A9/1y1 Airmatic pressure reduction valve

Example Faults:

• 5350 A9/1y1 (AIRmatic pressure release valve): Open Circuit.

What you will need

Mercedes Air Suspension Compressor

• Metric Sockets
  • 8mm, 12mm 
• Ratchet wrench
• Screwdriver
• Penetrating Oil
• Ramps or Jack
• Jack Stands
• Mercedes Air Compressor Relay
  • It is highly recommended to replace the Mercedes air compressor relay at the same time that you replace the air compressor.

Procedure

Before you proceed with the replacement of the air suspension compressor, inspect the wires that go to the air compressor for damage. Also, check for a bad connector at the air compressor. Check the air compressor relay to ensure it is working properly.

Below you will find instructions on how to replace Mercedes airmatic compressor.

1. Raise the vehicle at the front end. Secure the vehicle with jack stands. Place wheel chocks behind the rear wheels. 

   

    

2. Remove black plastic panel under the engine. There are three panels under the car. You only need to remove the first panel, right after the front bumper.
3. Once you remove the panel you will see the air compressor right behind the front bumper, underneath the headlight on the passenger side. You do not need to remove the front bumper.

    

4. Use a 12mm open-end wrench to disconnect the airline. There is a small rubber gasket on the metal connector at the end of the threads, make sure not to damage it.

    

5. Unplug two electrical connectors that go to the air compressor. One set of wires runs the compressor the other set runs the air release valve. Press the release tab on the connector then pull it. Do not pull the wires or you will damage them. 

6. Spray penetrating oil on the nuts before you remove them. These bolts break very easily, especially if they are rusted. 

7. Remove three 8 mm nuts.  Remove three nuts that hold the air compressor in place using 8 mm deep socket or open-end wrench.

   
8. Disconnect the air intake hose. Remove the hose that connects to the intake air filter. Use pliers to slide the clamp over then pull on the rubber hose.

9. Remove the air compressor unit. Install the new compressor. Assemble in reverse order. 

   

These instructions apply to most Mercedes-Benz models. The air compressor can be found on the right (passenger) front corner of the vehicle behind the bumper. It is in this location on most models including E, ML, GL, S, CLS class, etc.

Replacing Mercedes suspension air compressor is an easy procedure that can be performed by the vehicle owner in about one hour.

Notes

It is important to test a Mercedes-Benz air suspension compressor before replacing it. In some cases, the air compressor may run and appear to work properly but it does not generate enough pressure to raise the vehicle. 

You can use a multi-system diagnostic scanner such as Autel MaxiCOM to activate the air suspension compressor for 40 seconds. The compressor needs to between 16 and 35 bar in that time frame. 

If your Mercedes-Benz air suspension compressor does not generate 16 bar in 40 seconds it is faulty or there is a major air leak. 

If the compressor does not run at all it is either faulty or the wire harness to it is damaged. Othe possible problems include a faulty air suspension module.