Next service should be "A" - but "B3" showing on dash

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sonnenschein3000

New Member
Joined
Jan 29, 2020
Messages
10
Location
UK
Car
C257 CLS400d
Hi everyone

My next service should be an A service, if I have understood it correctly it goes A B A B A B...

My car (2021 CLS 400d) was registered in April 2021, and I bought it approved used in April 2023 (this year).

22nd April 2022 at 7,170 miles: A-service done by dealer
16th March 2023 at 10,712 miles: B-service done by dealer
in March 2024 or ~9000 miles' time: A-service should be done, but dashboard is saying it will be a "B3" service

I have entered the workshop menu and it is stating the following service items:
Service 02
Service 03
Service 08
Service 11
Because "Service 02" is listed, looking online that seems to mean that its a B-service even though logically an A-service should be due next (if it does indeed go A B A B A B etc.)

Does this mean that the car is asking for a B-service next? Or does B3 mean something else and it is still an A-service?
Is there something wrong with my ASSYST PLUS system or is there some other issue with my car, as to why it wants a B-service just 1 year after the last B-service?
 
If you enter your car details on this Mercedes Electronic Service Sheet, it will tell you what will be done at the next service.
I would say there is a glitch in the AssystPlus system as you certainly don't need another B service after having one last time.
There are age/mileage extras that may or may not be required as well as a normal A service.


This post, which should be a sticky so it can be referred to, tells you the meaning of the numbers and letters associated with the service.
 
Could the after service reset have been done twice accidently? I.e "b service done so system reset so next service is an "a" then it's been reset again so next service is now showing as a "b"?
 
Could the after service reset have been done twice accidently? I.e "b service done so system reset so next service is an "a" then it's been reset again so next service is now showing as a "b"?
If this is the case, can it be corrected?
 
If this is the case, can it be corrected?
I believe with Star you can wind a service back, but only once.
 
Is there a way one can find out what was exactly done on the service cos my newly acquired c class had a service A in oct 22 and then a service B in November 22! Really confusing!
 
Others have complained here before that ASSYST shows a different service to the one actually due. I don't know why, but evidently it happens. On my W204, ASSYST was showing (incorrectly) Service B due for a few months, and it then changed on its own accord to Service A due (which was correct). No idea why.

My suggestion is to ignore the instrument cluster and go by what the ESS says. If it really bothers you, raise it with the service advisor when the car is next at the dealer for a service, perhaps they can 'fix' it with their STAR. I would also ask them to update the instrument cluster firmware (under warranty), in case it's a software bug.
 
Hi everyone

My next service should be an A service, if I have understood it correctly it goes A B A B A B...

My car (2021 CLS 400d) was registered in April 2021, and I bought it approved used in April 2023 (this year).

22nd April 2022 at 7,170 miles: A-service done by dealer
16th March 2023 at 10,712 miles: B-service done by dealer
in March 2024 or ~9000 miles' time: A-service should be done, but dashboard is saying it will be a "B3" service

I have entered the workshop menu and it is stating the following service items:
Service 02
Service 03
Service 08
Service 11
Because "Service 02" is listed, looking online that seems to mean that its a B-service even though logically an A-service should be due next (if it does indeed go A B A B A B etc.)

Does this mean that the car is asking for a B-service next? Or does B3 mean something else and it is still an A-service?
Is there something wrong with my ASSYST PLUS system or is there some other issue with my car, as to why it wants a B-service just 1 year after the last B-service?
How many miles have you done now?

Are you forecasting that by the next service you’ll have done 9000 miles more than the last service in April 2023, or 9000 miles more than the current mileage?
 
How many miles have you done now?

Are you forecasting that by the next service you’ll have done 9000 miles more than the last service in April 2023, or 9000 miles more than the current mileage?
I'm currently at 17,211 miles
Its ~9000 miles to go from the current mileage, or March, whichever is sooner.
In my case it could be either/or, its roughly one at the same as it just so happens with my usage. So much so, the ASSYST PLUS indicator (without going into workshop menu) sometimes switches from days countdown to miles countdown and vice versa.
 
Others have complained here before that ASSYST shows a different service to the one actually due. I don't know why, but evidently it happens. On my W204, ASSYST was showing (incorrectly) Service B due for a few months, and it then changed on its own accord to Service A due (which was correct). No idea why.

My suggestion is to ignore the instrument cluster and go by what the ESS says. If it really bothers you, raise it with the service advisor when the car is next at the dealer for a service, perhaps they can 'fix' it with their STAR. I would also ask them to update the instrument cluster firmware (under warranty), in case it's a software bug.
Ah, that's interesting
So ASSYST PLUS isn't just a countdown clock (which I was assuming it mostly is), it seems as if it does do an element of thinking as well.
 
You might find watching my video:

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useful as this shows you how to access not only the reset menu but how to identify what work the car says needs doing. An explaination of the service codes is given in the video description.
 
I'm currently at 17,211 miles
Its ~9000 miles to go from the current mileage, or March, whichever is sooner.
In my case it could be either/or, its roughly one at the same as it just so happens with my usage. So much so, the ASSYST PLUS indicator (without going into workshop menu) sometimes switches from days countdown to miles countdown and vice versa.
I think the car will prompt you for a service based upon mileage rather than time, ie before April 2024.
 
You might find watching my video:

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

useful as this shows you how to access not only the reset menu but how to identify what work the car says needs doing. An explaination of the service codes is given in the video description.
Brilliant, thank you - i've liked and subscribed
I found the details in the description (especially the interval for each service item) to be very helpful, thank you, which means in my case...

In addition to 02 (B-Service) and 03 (Oil & Filter), my car is also asking for 08 (= Engine air filter) and 11 (= Diesel fuel filter) - both of which are 36 month service items, which will be the upcoming service. To me this indicates that the ASSYST PLUS system isn't out of sync, but is knowingly asking for a B-service whilst knowing that the upcoming service is a 36 month service.
Also, logcially speaking, if the ASSYST PLUS was out of sync by 1 year, I imagine that it would be asking for some of the 24-month items like brake fluid, for example - which it isn't
 
Brilliant, thank you - i've liked and subscribed
I found the details in the description (especially the interval for each service item) to be very helpful, thank you, which means in my case...

In addition to 02 (B-Service) and 03 (Oil & Filter), my car is also asking for 08 (= Engine air filter) and 11 (= Diesel fuel filter) - both of which are 36 month service items, which will be the upcoming service. To me this indicates that the ASSYST PLUS system isn't out of sync, but is knowingly asking for a B-service whilst knowing that the upcoming service is a 36 month service.
Also, logcially speaking, if the ASSYST PLUS was out of sync by 1 year, I imagine that it would be asking for some of the 24-month items like brake fluid, for example - which it isn't
Great - glad to have been of help and of thank you for the subscribe.
 

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