Common problems with Mercedes S-Class W221?

The Mercedes-Benz S-Class W221 is among the most advanced Mercedes models on the market. However, like all Mercedes, it has some common problems that you should know about before acquiring this luxurious car. So, what are the problems with the Mercedes S-Class W221?

The common problems with the Mercedes S-Class W221 include air suspension failure, transmission failure, window challenges, fragile level height sensor, air suspension airbag failure, auxiliary battery issues, amplifier problems, A/C blower failure, and many others. If you’re planning to buy the Mercedes S-Class W221, you should be ready to deal with most of these problems. 

Overall, the Mercedes S-Class W221 is among the most reliable Mercedes models of all time. Manufactured between 2005 and 2013, this car is the successor of the Mercedes S-Class W220 and the predecessor of Mercedes S-Class W220. Different Mercedes chassis come with different or more advanced features from their successors. 

Common issues with Mercedes S-Class W221


Like most Mercedes models, expect rust to be one of the main problems that you will face. If your Mercedes S-Class W221 has been around for some time, you may start to notice on the floor of the car, behind the license plate, and at the bottom of the doors. It is important to tackle rust before it spoils your car. 

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Air suspension compressor 

The Mercedes S-Class W221 comes with air suspension. However, the air compressor is at the heart of air suspension. This feature plays an important role in raising and lowering your car. So, if it fails or wears out, it might fail to create enough pressure to raise the car. As a result, your car will drop to the ground. 

The good news is that this can be done corrected by replacing the air compressor. Unlike in the past where air compressors were very costly, you can find one online at around $150. Replacing this part is also easy and you can do it if you have some motor DIY skills. 

Auxiliary battery 

This Mercedes model comes with two batteries. It has the main battery that starts the engine and the auxiliary battery that runs several electronics in the vehicle. Since this car is also equipped with an electronic transmission shifter, the auxiliary battery can be used to put the car in park if the main battery fails. 

After using the auxiliary battery for some time, this battery will fail. This usually occurs to Mercedes S-Class W221 that has covered more than 100,000 miles or 6 years. All you have to do is to replace the battery and have everything running smoothly. 

Transmission failure 

Aside from the above issues, another common problem that Mercedes S-Class W221 owners will face is a failed transmission. However, this issue is more common in W221 pre-facelift models made between 2007 and 2009. The failure is normally caused by the electronics in the 722.9 7-speed automatic transmissions. 

The problem can emanate from the transmission control unit, the conductor plate, or the valve body. If one of these transmission parts fails, it will send the car into limp mode and the transmission will no longer shift. Nonetheless, replacing the transmission or valve body is quite cumbersome and costly. 

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Window issues 

Another common problem that you’re likely to face with the Mercedes W221 is a window that fails to be raised or lowered. In most cases, it is because of either a bad window regulator or a failed module. Find out what’s the cause and replace the right part to avoid such a problem.  

The window regular is the system that moves the window up and down, while the window module is the system that controls the window operation. 

Amplifier problems 

The amplifier is also another common problem that the Mercedes W221 faces. If this part fails, things like the car’s radio will turn on, but you won’t hear any sound. Also, the COMAND may fail to turn and the battery may drain when the car is parked. Replace it immediately to avoid having such challenges. 

Air suspension airbag failure 

This problem is not only common with the Mercedes S-Class W221 but all the other Mercedes chassis. If your Benz passes the 100,000-mile mark, be ready to deal with a failed or unreliable air suspension bag. Besides, this problem is common for city drivers or people who use poorly maintained roads. 


Is the Mercedes S-Class W221 reliable?

Yes, the Mercedes S-Class W221 is a reliable car. But like most Mercedes-Benz models, expect to spend a lot in terms of repair and maintenance. The costs of repair and maintenance will even go up further after you hit over 100,000 miles. 

Is the S-Class model expensive to maintain?

Since this model comes with more advanced features than the Mercedes C-Class or E-Class, expect it to be very expensive to maintain. However, it’s somewhat more reliable than the Mercedes A-Class and C-Class. Overall, you will spend more money to maintain this car when it runs out of warranty. 

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What year is Mercedes W221? 

The Mercedes-Benz S-Class W221 was manufactured between 2005 and 2013. While other Mercedes plants around the world were able to manufacturer this model from 2006 to 2013, Canada and the USA started production from 2007 to 2013. This car has assembling plants in Germany, Mexico, Egypt, Malaysia, and Indonesia. 

Do all Mercedes S-Class have the same problems? 

No, even though most Mercedes-Benz models share most of the problems such as rust, suspension, window regulators, Airmatic parts, and transmission issues, some issues differ from model and year of manufacturer. So, before you buy a particular Mercedes model, find out which problems the car faces. 


Now that you know which problems the Mercedes S-Class W221 faces, it is important to be on the lookout and amend them in good time. Most of the problems that we’ve discussed above usually appear after your Mercedes S-Class W221has covered over 100k miles. 

With regular inspection and maintaining scheduled service, your car should be in a good condition for the most of ownership. 

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Edwin Odipo

Why do you love writing about cars? Cars make our lives easy. You can visit your distant friend, relative or even rush to the grocery store a few miles from your home with a lot of ease. Imagine how life was before the invention of cars?? To me, cars are a blessing that made life more convenient.

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