Are you seeing a “Service B9 Due” message on the dashboard while driving your Mercedes? Is there a reason for this message? Don’t worry! There’s nothing to worry about!
This article describes in detail the Mercedes B9 service code, what is included in the maintenance checklist, and how to reset and repair the indicator after servicing. Without further ado, let’s get started!
What Is A Mercedes B9 Service?

In order to maintain a Mercedes vehicle’s performance, durability, and lifespan, it requires two types of services (A and B). A Mercedes B9 service involves a comprehensive inspection of engine components, transmission components, and brake components.
Using Mercedes’ latest service schedule, the B9 service prevents potential health problems in your car. Basically, it’s a one-stop shop for all aspects of car performance that could be improved.
What items are included In the Mercedes B9 service?
That particular service involves multiple items, each of which has its own significance. Nevertheless, here is a summary of the items included in Mercedes-Benz service B9:
- Oil and filter replacement
- Brake fluid change
- Spark plugs replacement
- Air filter replacement
- Wiper blade inspection/replacement
- ATF (Automatic Transmission Fluid) replacement
Oil And Filter Replacement
It is crucial to replace the old engine oil with new one as soon as possible. By doing so, the mechanic ensures the engine’s moving parts will operate smoothly and efficiently without overheating by draining the old oil and replacing it with new oil.
My recommendation is to use genuine Mercedes oil in order to lubricate the engine of your vehicle. In comparison to other local oils, it provides greater durability and long-term performance.
Brake Fluid Change
Among other hydraulic systems, this type of fluid is used to brake vehicles. A vehicle comes to a complete stop when the brake pedals are pressed because the brake fluid transfers force into pressure.
It is only capable of performing well for a certain period of time before losing its quality and reliability. It will be necessary for the technicians to drain the old fluid from the master cylinder reservoir and replace it with fresh fluid.
Afterwards, he will check if the brake pads and rotors are in need of replacement.
Spark Plugs Replacement
Air/fuel mixtures are ignited by spark plugs, which generate electricity in the engine. As well as spark plugs igniting fuel in the combustion chamber, spark plugs power the vehicle’s other systems.
If you have 30,000 miles on your car, you should change your spark plugs once every 30,000 miles. However, there are extended-range plugs that last for up to 100,000 miles.
Thus, you should always use genuine, high-quality spark plugs to protect your car’s engine and optimize fuel efficiency.
Air Filter Replacement
It’s no secret that engine parts such as the air filter do a great job. In addition, it prevents air from entering the combustion chamber, and it improves the efficiency of engines when it is dirt-free and clean.
As a result, most dealers recommend changing the air filter at least every 90 days or 3 months for your engine to stay cooler and more efficient.
Wiper Blades Inspection/Replacement
In foggy, snowy, rainy, or dusty weather, an inspection and cleaning of the wiper blade is essential.
If your Mercedes windshield is scratched or streaked due to worn out wiper blades, you may need to replace them. In order to maintain their quality, they need to be inspected regularly as they wear and tear over time.
In addition, new wiper blades may need to be replaced.
ATF Replacement
As part of B9 service, automatic transmission fluids (ATFs) perform a variety of tasks relating to transmission protection, heat dissipation, and lubrication.
You may find that replacing ATF when your vehicle’s transmission needs it to prolong its life is a worthwhile investment.
It is recommended to change the ATF every 30,000-60,000 miles (for manual) according to most experts.
Mercedes B9 Service Checklist

No. | Service Items |
1 | Oil and filter replacement |
2 | Brake fluid change |
3 | Spark plug replacement |
4 | Air filter replacement |
5 | Wiper blade inspection/replacement |
6 | ATF (Automatic Transmission Fluid) replacement |
What Is Mercedes B9 Service Cost?
There is an average cost of about $700 to $1500 for B9 service. It is possible that the price mentioned is slightly low or high, and you can get an exact price from your dealership.
It is important to note, however, that the total cost can vary depending on these factors:
- Car model
- Labor rate
- Location
Car Model
There is a link between the Mercedes-Benz model you own and the B9 service price since Mercedes-Benz models with the latest technology have higher service charges than those with older models.
Labor Rate
There are many factors that can determine labor rates, such as experience, certifications, and brand identity. Having received professional training and having in-depth knowledge allows highly skilled technicians to charge high rates.
Location
When it comes to getting B9 service, location is also crucial. The cost of Mercedes B9 Service may vary depending on whether an owner lives in the USA or the UK. An owner in the USA may pay $700 to $1500, while an owner in the UK may pay more or less.
Why Is A Mercedes-Benz B9 Service So Expensive?

In most cases, Mercedes-Benz owners wonder why service maintenance on B9 models is so expensive. In this article, I explain a few factors that will reduce their complaints about the price of the service.
Exclusive Image Of Mercedes
The luxurious nature of Mercedes cars makes it one of the world’s top automakers. For this reason, owners are willing to spend more on Mercedes in order to maintain their exclusive image.
Expensive Tools And Gadgets
A mechanic must purchase extremely expensive advanced diagnostic tools, computers, and scanners in order to inspect a vehicle accurately and completely.
Highly Trained Technicians
Since Mercedes vehicles are complex, their technicians must undergo stringent training, degrees, and certifications to maintain them.
Expensive Auto Parts
Mercedes B9 maintenance uses genuine parts to ensure your Mercedes-Benz’s exceptional performance remains at its peak. There is a significant price difference between these parts and aftermarket components.
Tips To Make Good Choice
Here are some tips from a Mercedes mechanic that you can use to make an informed decision when choosing a B9 service.
- If you are going to have your car maintained, make sure you ask your garage how much it will cost and keep some extra cash in the bank.
- It’s always a good idea to read the reviews and ratings of your selected shop before taking their services.
- Your mechanic will be able to better diagnose the condition of the vehicle if you share your driving experience and vehicle faults with him.
- If you are interested in a service plan, ask if there are coupon codes or discounts available.
How Long Does A B9 Service Take?
Depending on the season, appointment time, and the number of people already waiting for service, the B9 service can take from 2 to 4 hours, but it can take up to 5 hours.
It is possible for your vehicle to require more maintenance than typical at times, which may take more time. A booking an appointment before visiting the shop is advisable during busy seasons, when the shop is packed with clients waiting for service.
Service B9: DIY Vs Professional
It is also essential to know everything you need to know about the vehicle for the B9 Service in order to complete it correctly. The risks associated with doing that without any technical knowledge, however, are considerable.
In order to perform maintenance tasks correctly, a professional mechanic should have expertise and special tools. It is therefore recommended that B9 services be performed by a professional, like me (including the majority of other techs).
Can I Do A B9 Service Myself?
The B9 service can be performed by yourself if you have deep technical knowledge, the necessary tools, and experience with DIY maintenance. As a result, I always recommend getting it repaired by a Mercedes service center that is accredited.
When To Change The Air Filter?
HVAC companies and air filter manufacturers recommend replacing filters every 90 days or 3 months, respectively. You may experience a different experience depending on your location and dusty or dry climate. Consult an expert if you need advice.
When To Change Spark Plugs?
The schedule for replacing spark plugs varies depending on factors such as driving habits, engine conditions, and other factors. There is a recommendation that drivers change their spark plugs once every 30,000 miles, but extended range spark plugs can last up to 100,000 miles.
When To Change Automatic Transmission Fluid?
- In the case of manual transmissions, every 30,000 to 60,000 miles
- For automatic transmissions, it should be done every 60,000 to 100,000 miles
It is recommended that manual transmission fluid be replaced every 30,000 to 60,000 miles. There is no problem if you replace fluid early if your automatic vehicle has a range of 60,000 to 100,000 miles.
How To Reset B9 Service Notification On A Mercedes?
It is not necessary to schedule an appointment to reset the warning message after the B9 maintenance. The process only takes a few minutes. The following video guides you through the process of resetting service notifications:
Read: Mercedes B5 Service
Read: Mercedes A3 Service
Read: Service B3 Mercedes
Read: Service A5 Mercedes
Conclusion
Vehicles that are properly maintained always have a distinct advantage in the resale market. Likewise, regular service prevents passengers from discovering small problems with their vehicles before they become major problems.
As a result of our article, we concluded that Mercedes-Benz models require the B9 service to be properly maintained. There are a number of sub-items included in this, such as oil and filter changes, spark plug replacements, and air filter replacements.
You should always get service or visit a garage or repair shop as soon as possible whenever an error message like “B9 Due, Mercedes B9 Service” appears on your Mercedes Dash.
You shouldn’t ignore dashboard warning lights or delay getting service without good reason in order to enjoy a comfortable ride.