If your Mercedes is equipped with an Airmatic suspension system and you suddenly feel your car sit lower than usual, you probably have a faulty air suspension compressor. This guide provides instructions on how to diagnose a Mercedes Benz’s Airmatic (suspension) compressor.
What you will need
One of the symptoms of a bad airmatic suspension compressor is the unusually low height of your car on all four wheels. The problem may not always be the air compressor, but you have to isolate the air compressor first.
- Get a hold of a professional scanner.
- Park the car on a flat surface and set your parking brake on.
- Locate the OBD-II port. To find the OBD-II port, open the driver’s side door and look under the dash; you will find it next to the red hood release lever.
- Pull the cover down and plug in your OBD-II scanner.
- Shift the vehicle into the park. In some models, you have to start the engine so that the air suspension module would go online. On other models, turning the ignition on would suffice.
- Depending on the scanner, you may need to choose the make of the car, navigate to the system menu, go to chassis, and then suspension. The most important step is to read the suspension fault codes.
- If the scanner reports an error similar to “Recovery time to fill a central reservoir is too long,” the code’s status is current or current and stored. Then, the problem is that the air compressor is working too hard to fill the central air reservoir with a recommended pressure of 13-16 bar.
- To verify if the compressor is faulty, again, depending on the scanner, there would be another menu before you could get to the Pneumatic Test. In the Pneumatic Test, choose the Airmatic Control Unit. This command will open the Airmatic relief valve on the air compressor for forty seconds to release air from the suspension. The compressor will turn on for forty seconds while the pressure sensor measures the air pressure. If the compressor fails to fill the tank with 16 bars within forty seconds, then the fault will be stored again, and definitely, your air compressor has a problem and needs replacement.
Troubleshooting with YOUCANIC Full System Scanner
The YOUCANIC Full System Scanner is a perfect example of an OBD-II scanner for troubleshooting your Airmatic System. This powerful device can perform bi-directional tests and display live data to determine the problem. It can also read and clear fault codes from all the systems, maintenance and repair resets, and many more professional-grade functions.
Access Factory Repair Manuals
The YOUCANIC Pro Manuals offer OEM Factory Repair Manuals with detailed steps and illustrations, comprehensive wiring diagrams, torque specifications, and access to technical service bulletins and OEM service information, mirroring dealership manuals.
Frequently Asked Questions
What is a central airmatic reservoir?
The central reservoir is a metal pressure vessel that stores compressed air at 13-16 bars and levels the vehicle. This tank is incorporated to reduce the dependency on the air compressor and to reduce noise. The tank is most commonly used to level the vehicle when opening the door or trunk.
What are the components of the Airmatic suspension system?
Airmatic Control Module
Level and Damping Control Switch
Valve Block Assembly
Strut & Damper Assembly
Rear Axle Distribution Block
What is the lifespan of a Mercedes Benz Airmatic compressor?
You have to replace it every 125,000 miles.
Mercedes-Benz E-Class (W211)
- E500: Model years 2003-2006
- E550: Model years 2007-2009
- E55: Model years 2003-2006
- E63: Model years 2007-2009
Mercedes-Benz CLS-Class (W219)
- CLS500: Model year 2006
- CLS55: Model year 2006
- CLS550: Model years 2007-2011
- CLS63: Model years 2007-2011
We hope you find the Mercedes-Benz Test Air Suspension Compressor guide helpful. Check these troubleshooting and repair guides for more help on your Mercedes-Benz.