• Greetings, could someone explain why the service indicator popped up for a "B9" service at only ~60,000 miles? I was under the impression this service typically occurs at over 110,000 miles.
• Also, what’s the difference between a B9 service and the standard B service? (I see many variations online for this and alway somewhat different than the service booklet)

Thank you
US version 2020 GLC300 4Matic.

 

A and B service indications alternate and increment in the sequence A1, B1, A2, B2, etc., and advance by resetting the service indicator regardless of time or mileage. After resetting, it might indicate Service An is due in x days or y miles, but this doesn't prevent the indicator from being reset early and then showing Service Bn is due next. While normally you might expect A and B services to synchronize every 10K miles/12 months, and so at 60K you should be at B3, your car's service indicator has been reset far more frequently. Even with 5K oil changes, you would be showing B6. Do you have the service records or know anything about the car's service history?

 

@streborx , I've reviewed all the records, and it looks like the maintenance schedule follows an A & B service pattern every 10,000 miles. My mistake was not getting the oil changed every 5,000 miles—is that actually necessary or just an urban myth?
Now, I'm at 60,000 miles and due for a B service. However, the 'No.9' detail has confused me, and I want to avoid being overcharged by my mechanic for unnecessary work related to it. Is there a chance they could mess up the resets or inflate the service requirements for the B service?

Does this capture what you wanted to say accurately?
~50,000 A service with indy replacing OEM Iridium Spark Plugs recommended by millage;
~40,000 FlexB, B service by MB dealer.
~30,000 A service by MB dealer.
etc.

 

My reply only was intended to explain the possible reasons why a B9 indication would appear at 60K miles.
Oil change intervals are entirely a matter of individual choice. I chose 5K miles or 12 months, whichever occurs first. Others prefer more frequent oil changes and others insist less frequent is fine.
Inasmuch as A# and B# service indications are entirely a matter of resetting the service indicator, they don't necessarily correlate with either total mileage or total elapsed time. They are more of a reminder to do "something".
I am 10 days away from doing B3 at 60 months and 23K miles. I'm doing an oil change, cleaning the filters, doing fluid, brake and wiper checks, but I'm nowhere near sparkplugs and gearbox fluids. If this B3 was to be at 60 months and 50K miles, sparkplugs and gearboxes would be on my list.
IMO, the A and B service indications are intended to prompt you to seek service at a dealership where you'll be told what and how much. A "B1" indication doesn't mean a brake fluid change if it occurs at 6 months and 15K miles after driving off the lot. But if B1 occurs at 24 months and 20K miles, it does.
MB stopped publishing service and maintenance guides, and has left owners to the whims of dealership service departments. Some are honest while others will try to sell you a $6,000 brake job at 25K miles as preventative maintenance, before any wear indicator pops up on the dash.
At 60K miles, what needs to be done depends on what has been done previously, and what car you own and its maintenance requirements.
The last maintenance guide I've been able to find is from 2016, and a copy is attached. It might help in determining what needs to be done.

 

Thank you, @streborx ! Are you on the business side or more involved in the technical aspects? That was a great response, much appreciated. Follow up question: with these advanced smart cars, can a mechanic generate a detailed report of past services and dates and he can then proceed on what's needed beyond a B service (that's if he's trust worthy of course)? I'll review the attached PDF as well.

 

Yes. Your service advisor has that at his workstation.
However some dealerships consider this "proprietary" and may quibble.
It's pretty lengthy.