Experiencing one of the following problems:
- Vehicle too low. Visit workshop. Warning on Instrument Cluster
- Airmatic Malfunction Warning on the dashboard.
- AIRMATIC VISIT WORKSHOP!
- AIRMATIC – STOP, CAR TOO LOW!
- Mercedes-Benz is sagging in front or back.
- Mercedes-Benz lowered to the ground, all four wheels.
Whether you decide to repair the air suspension yourself or have a mechanic do the work, read this troubleshooting guide first so that you are educated on what to expect. Otherwise you may end up paying thousands for AIRmatic repairs that you don’t need.
Driving a car with air or hydraulic suspension is a dream come true. This system is often called AIRmatic, airlift, air ride or hydraulic Active Body Control (ABC) suspension. In how many cars can you change the suspension settings from comfort to sport with a push of a button? Raise the vehicle a few centimeters in just a few seconds. Now there are plenty of aftermarket airlift conversion kits, but on several Mercedes-Benz models, AIRMatic suspension is factory installed.
Learn how to troubleshoot Mercedes-Benz Air Suspension Problems.
You decide to buy a Mercedes-Benz, maybe an S-Class, CLS-Class, R-Class, CL-Class or E-Class. One day you hear of other Mercedes-Benz owners having suspension problems. The next day you start having air suspension problems yourself. Your Mercedes-Benz drops to the ground and you may even end up towing your car, because it is no longer drivable. Now your dreams are replaced with nightmares.
You take your Mercedes-Benz in for a diagnosis and get quoted thousands of dollars for air suspension repair. What’s even worse is that there are only a few select shops that know how to fix them. If you are a new owner or mechanics that haven’t worked on air suspension before we will guide you through the steps on how to troubleshoot some of the most common air suspension problems yourself. If you are having issues with the air suspension on your Mercedes-Benz, this troubleshooting guide is for you. You will be surprised when you realize that the air suspension is not that complex.
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A brief overview of the air suspension
The suspension on Mercedes-Benz cars equipped with air suspension is controlled by the Air Suspension Control Unit (N51). The driver can select the driving mode, switching between Comfort and different Sport modes. The vehicle level is continually monitored and readjusted whenever there is a difference of more than +/- 20 mm. The suspension will also adapt to the road conditions and the driving style. At the vehicle reaches over 40 mph, the car lowers so that the center of gravity is closer to the ground, therefore improving handling, cornering, reducing drag, vehicle lift, and rollover risk. This sophisticated system makes you feel like floating when you ride a Mercedes-Benz until the airlift suspension fails.
First, let’s look at some of the warning signs and symptoms of airmatic suspension problems. On the instrument cluster you will get two messages. The first is the Air Suspension Failure, Visit Workshop, and the second is more critical offten shown in red: STOP VEHICLE TOO LOW.
“AIRMATIC VISIT WORKSHOP!” message on the instrument cluster.
This is typically an electrical fault. You will need an OBD II scanner such as Star Diagnostic or iCarsoft MB II to read the fault codes.
Once you scan the car you may get fault codes. For example, you will get C1324-001 or C1325-001 which mean a communication or fault is present by the solenoid valves in assembly Y53 ( rear axle damping valve unit). It could also be that there is a discontinuity problem with any of the air suspensions components. This will difficult to track down without a scanner.
If you get the AIRMATIC Visit Workshop message, your car may still drive but do get it checked out as soon as possible. If the car drops over the next few days, the air suspension may not work to airlift the car.
“AIRMATIC STOP, CAR TOO LOW!”
This message may be scary. Don’t panic! Note that the car in most cases will drop too much and you will not be able to drive it. If the air suspension has collapsed, unfortunately the car will not be drivable at all.
What are the most common failures?
Summary of the most common problems with Mercedes-Benz air suspension systems, DIY solutions are provided in the next section:
- Air suspension compressor Failed (Easy DIY repair, Average cost $200) The air suspension compressor does just that, generates compressed air. It fills up all the air struts, and it can fail. They either seize up, fail to produce the required pressure or the brushes inside them wear out. In the next section, we will show you how to check if the air suspension compressor is the problem. Sometimes it could be a just a $5 faulty relay that may prevent the air suspension compressor from running.
- Failed Air Strut The air struts leaking is a very common problem. They end up developing a leak at the mastic at the top of the strut. Below we show you how to test your air struts for leaks. When the seal in the strut degrades it no longer provides the isolation required and a leak starts. If a major leak has developed, you may even hear a hissing sound from the wheel housing area. The whole front or rear of the car will drop down, even when only one of the struts is defective. The car will drop more on one side, typically on the side of the leaking air strut.
- Leaking lines The lines that supply the compressed air to the strut can also develop cracks and eventually air may leak.
- Faulty relay or Blown Fuse The air suspension compressor relay is known to fail. It could either not engage the air suspension compressor at all or even worse keep it engaged for longer that required. If the air suspension compressor is kept engaged for too long, it can get damaged. There is the chance of a blown fuse for the air compressor pump. You can replace the fuse with a new one but if it keeps on blowing you have another issue, usually pointing at the air compressor pump / motor. For example on the Mercedes-Benz S-Class W220, there is a air compressor relay and fuse 32 on the fuse box located on the passenger side of the engine compartment. Here is a picture that shows where they are located.
- Valve block leaking The main problem with the valve block is that the solenoid valves may leak air back to the compressor or the central air reservoir. This can cause the vehicle to not maintain the ride height required. If you need help with troubleshooting the airmatic valve assembly watch this video.
- Level sensor is faulty They are located at the rear and front suspension. When they stop working the air suspension control unit may no longer be able to recognize the height of the car. Your Mercedes-Benz will greet you with a warning message on the dash related to the airmatic failure. The car height may be correct and the car still rides fine, it’s just that the computer doesn’t know that.
- Brass valves at the top of the strut. Leaking due to the metal on metal fitting between the brass valve and the strut connection.
Air Suspension Troubleshooting
In the following video you will learn how to use a Autel MaxiDAS DS708 to diagnose Mercedes-Benz air suspension problems.
Faulty Relay or Blown Fuse for air suspension compressor
One of the first items that you should inspect is the air suspension / airmatic relay in the main fuse box in the engine compartment. Also, check the fuse for the air suspension compressor. On the Mercedes-Benz S-Class, the fuse box that contains the air suspension compressor relay and fuse are located on the right (passenger side) of the engine. Look at the 40 AMP fuse F32, make sure that it is not blown. If the fuse keeps on blowing this typically points to air suspension compressor issue. Find the fuse and relay that are for the air suspension.
In the following video we will show you how to check the relay on a Mercedes-Benz W220 S-Class (S430, S500, S600, S55 AMG and CL500, CL600). Procedures are similar for other Mercedes-Benz with air suspension, but the location of the relay and fuse may change.
In this S-Class W220, the air compressor motor /pump is protected by Fuse 32, which is a MaxiFuse 40 Amp. Here is what a good fuse should look like.
You can purchase a new relay and eliminate the possibility of the relay being the problem. The relay that is known to be reliable is Multi-Purpose Relay for Air Pump Suspension 0027219 by Hella
How do you test if the air suspension compressor is working?
Typically when the air suspension compressor quits working, the whole car may lower to the ground and fail to raise. You press the button to raise the car, and nothing happenes. If the air suspension compressor works as designed, you will hear the compressor engage and run for several seconds.
Do you hear the air suspension compressor kick in at all?
If not, we need to do further troubleshooting. How can you check if the air suspension compressor is not working / engaging.
Check voltage at the air compressor
- Locate the air suspension compressor. It is behind the front bumper. Right under the headlight. You can access it by removing the plastic cover in the wheel well.
- Check if power is going to the air suspension compressor. You can unplug the electrical connector that goes to the air suspension compressor, as shown in the picture below.
- Use a multimeter to test if there is 12-volt power at the connector. If you don’t have a multimeter, consider getting one as they are very useful when it comes to car troubleshooting, here is a list of highly rated digital multimeters. Remember that you need to press the Raise Vehicle button to engage the compressor as it does not work constantly.
If you get a very low reading, then we need to look at the relay and the fuse. If there is no power going to the air suspension compressor, check the air suspension fuse and relay. Here is a picture that shows no power to the air suspension pump.
The next step would be to use a professional diagnostic scanner such as the iCarsoft MB II to check the fault codes for the Air Suspension Control Unit. You will have to invest around $200 on the scanner, but it will pay for itself in a short period. If you plan on owning a Mercedes-Benz for a while, then consider investing on one of the advanced OBD II scanners mentioned above. It will make troubleshooting your Mercedes-Benz much more easy. You will be able to check any of control units for fault codes and reset them.
Failed, defective air suspension compressor / pump.
If there is 12 volt or higher going to the air suspension compressor, but the compressor does not engage then you have a defective air suspension compressor. Another symptoms that generally points to a failed air compressor is when your Mercedes-Benz is completely lowered to the ground on all four wheels. Follow these instructions on how to change the air suspension compressor.
Follow these DIY instructions on how to replace the air compressor.
Failed Air Strut
If one of the air struts fails, typically the vehicle will fall only on the front or rear end, depending where the faulty air strut is located. This is because if one of the failed air struts is on the front passenger side, the driver side will also sag. Only one strut on the front is not able to keep the front of the car up. If you investigate closely, you may notice that as the front or the back of the car drops, it will drop more on one side than the other. The wheel where you see the car lowered the most, is typically the air strut that may be leaking. There are top seals in the strut that fail or wear and over time, they will develop air leaks.
You have the option of replacing the air strut with a new one, but if you get a quote on this repair, you may end up regretting that you bought a Mercedes-Benz. Don’t worry; there are a couple of Do It Yourself solutions to this problem that will not break the bank.
- You can use Epoxy Hack(Cheap and Dirty Repair, usually works)
- Airmatic Strut Shock Repair Kit (Official repair, still much less expensive that strut replacement)
These solutions have shown to work. Some auto repair shops may not try the epoxy solution, as they can’t guarantee their work, plus they don’t make much profit. If you don’t feel comfortable with the two solutions mentioned above your next best bet would be to install a refurbished or new Arnott air strut. They are a little bit more expensive that the two solutions proposed above but still cheaper than replacing with dealer parts. You can find Arnott air suspension compressor and struts on Amazon. You can check the latest prices by visiting the Arnott air suspension Online Products
This is the least expensive solution. It is not guaranteed as how long this will last. It can last for years or months. It may be worth trying, but do some research before you decide to try this approach. You can complete this repair in just a few hours if you have the patience and about $20 to invest. This is what you will need.
Required Tools and Materials
Click here to download instructions on how to perform this repair provided by robledoch BenzWorld Member.
Let the epoxy cure completely. If you use the J-B Weld Epoxy, it takes up to 16-24 hours for it to cure fully. There are epoxy compounds that cure faster, make sure to read the direction on the back of the epoxy to allow it to cure before you pressurize the system again.
As you fill the air struts/spring again, make sure the bellow covers are extended all the way down and are not folded upwards. You can pull the covers downwards by hand. Once you do this, lower the car before you activate the air suspension and pressurize the system.
Once you complete this repair make sure to use tape to seal the brass fitting on top of the air strut. Otherwise, you may have a small leak that will develop and cause your car to drop when parked for a few days.
Airmatic Strut Shock Repair Kit
This is the same repair that is often performed by Mercedes-Benz dealerships. In this process, you need to remove the top seal and replace it. The root cause of strut failures. Here is an original listing of the Mercedes Benz Air Suspension Strut Shock repair kit Part Number 2203202538
Here you will find the WIS instructions on how to replace the top seal.
To replace the air strut seal, you will need the replacement kit.
Watch this video on how to replace the top strut seal.
Note that the repair itself is not difficult. it is important that you fill the air spring plunger properly. There are a couple of ways to perform this. You could either pull down on the air spring plunger as you activate the fill / raise process of the air suspension. This is described in detail in this document that you will find here: How Mercedes-Benz dealer fills the air suspension spring (PDF). If you accidently damage the air spring bellow covers, you can purchase new ones online without having to replace the whole strut.
Inspect for air leaks.
Air leaks are difficult to troubleshoot, especially if you use water and soap method. You basically will be spraying the lines and the different components with soap and water and look out for air bubbles. While it can be done with soap and water, to make this challenging task easier, we recommend using a solution that is designed to help you find air leaks. Most of these products cost less than $10 and help you find the air leaks much faster and easier. One of our favorite leak detectors is the Hercules Mega Bubble Leak Detector, which sells for less than $10 on Amazon. With this leak detector, even if there is a small leak it will show a bubble immediately which you may miss with soap and water mix.
Once you choose the solution of your choice, you need to spray the solution at the following locations.
- air suspension compressor fitting
- Air Lines
- Fittings at the valve block
- Spray along the air hoses
- Connection at the air tank / central air reservoir
- Joints, brass valve on top of the air struts
- Level control valve block
As you apply the leak detector on these locations, check them in the next 5 to 15 minutes. Some leaks are soo small; they may take a few moments to form.
The valve block is less likely to be the problem, but they are known to fail as well. To be able to test the valve block you need to disconnect the lines to the compressor or the air reservoir. Apply leak detector at those locations to make sure they are not leaking.
If you find any of the lines, pipes, hoses leaking, you will need to purchase airlines to repair the damaged section. You will often find the air lines on eBay for much cheaper, click here to check active listings.
Level Control Valve Block
The valve block unit (Y36/6) is located near the air suspension compressor. In the case of the W220 S-Class, it is located on the right side, between the passenger side headlight and the air suspension compressor. The valve block contains valves which open and close to direct the air pressure that is sent to each air sturt. The air is feed from the air suspension compressor or the air reservoir.
At the wheel equipped with the air strut, you will also find the level sensor. These sensors are used to gather information on the level at the axle. If the sensors don’t function properly, they can trigger an AirMatic malfunction on in instrument cluster.
The sensors detect the vehicle level at the axle and sends a resistance reading to the air suspension control unit.
There are several sensors located in the vehicle that provide data and feedback for the air suspension control unit. Some of these components include:
- ESP control module
- Engine control module
- Transmission control module
- Instrument cluster
- Steering angle sensor
- Comfort and sport switch
- Level adjustment switch
- Vertical and horizontal accelerometers
- Front axle level sensors
- Airmatic pressure sensor
Most owners don’t even know that there is an air suspension compressor filter. After all, it is well hidden. The air suspension compressor filter should be replaced as it is considered a maintenance item. If the filter gets clogged, it can dramatically impact the life and efficiency of the air suspension compressor. The filter part number A2203200069 costs only a few dollars when purchased online.
Check the price on Amazon.
Check the price on eBay.
Alternative – Convert Air Suspension to Coil Spring
Some owners end up spending a significant amount of money on the air suspension repairs. You may want to consider air suspension removal and convert the four wheels to coil springs. There are aftermarket suspension conversion kits for Mercedes-Benz that even include the fix for the control module so that you never get that air suspension warning message again.
Converting to coil springs will cost you between $1200 to $1500 for parts alone. Strutmasters are a well-known brand that make aftermarket air suspension conversion kits. You will find their kits on Amazon. Here are some listings so that you can get the idea of how much it will cost to buy these kits.
Hopefully this article helped you find the problem with your suspension and you were able to fix it without spending thousands of dollars. It is very likely that 8 out of 10 owners may have one of the problems described here.
If all fails, there is another way to diagnose the air suspension. You can use a diagnostic scanner that can retrieve the fault codes and erase them. Most advanced OBD II scanners will read and clear the airbag, air suspension, transmission and other system trouble codes. It will be even better if you have a Mercedes-Benz Star Diagnostic C3 or C4, with which you will be able to carry a series of test to determine which component of the air suspension has failed. Often you can find the Mercedes-Benz Star Diagnostic C3 and C4 on online. For example here are some listings on Amazon and eBay.
If a Star Diagnostic scanner is out of budget you should consider the less expensive professional diagnostic scanners which allow you to read and erase fault codes. You will be investing around $200 on an OBD II scanner, but it will pay for itself in just one use. Once you connected the scanner into the diagnostic port located under the dash on driver’s side, you will be able to retrieve the fault codes from any of the control units in your Mercedes-Benz. You need a scanner that can read and clear codes for multiple systems such as the AirBag, ABS, Engine, Transmission and also the Air Suspension Control Unit. A simple OBD II can not read more than just the Engine Electronics, ECU. One that can access multiple control units and we recommend is the iCarsoft MB II.
If you tried the tips and tricks on this page and still can’t find the problem, then your next step is to obtain a diagnostic scanner for further diagnosis and troubleshooting. Plug the scanner into the OBD II port and it will tell you more about your problem than what we can in this article.
Air Suspension AIRMatic and ABC Encyclopedia Resources
- Assembly Instructions Mercedes S-Class DC W220 Airmatic (not models with ABC)
- Airmatic Shock Installation Mercedes-Benz S-Class W220 by Bilstein
- Overview of AirMatic Documentation WIS
- Mercedes Benz W220 Front Air Spring Replacement (VIDEO)
- Mercedes Benz S-Class Front Air Shock Replacement with Arnott Aftermarket Replacement Parts
- Air Suspension Fix Documentation (Forum thread on BenzWord)
- Rear Air Strut Removal and Installation of Arnott Replacement Parts
- Mercedes Benz ABC System Troubleshooting Guide
- AirMatic In Depth Review