LenniePaz

I just got a message saying Service B is due, but an A is the one that's due. I'm at 50k so that's an A, correct? How can I get it so it's back in the correct order?

streborx

Over how many months has 50K miles been driven?

W205C43PFL

It is both mileage and time based. If the 50K miles was reached by the 5th year, it would had been Service A but if it was the 4th or 6th year, it is indeed service B.

LenniePaz

I have a 2019 GLC 300 so it's 5 years. My last service was a B.

LenniePaz

I don't understand the question.

streborx

A and B services alternate and occur at 12 month or 10K mile intervals, whichever is reached first. While you're at 50K / 60 months, it would seem an A service should be due, but mileage/time accumulation could occur as follows:

10K miles - 12 months >> A service
15K miles - 24 months >> B service
20K miles - 36 months >> A service
30K miles - 48 months >> B service
40K miles - 54 months >> A service
50K miles - 60 months >> B service

Is your car indicating "B3" service? That would confirm that something such as the above has occurred.

LenniePaz

I think I do remember seeing the B3 service reminder when it popped up. If it does, then what service is due? My 40k was a B.

streborx

If your 40K was B2 and it was 2 years ago, you should do B3 as the oil change and brake fluid change per MB recommendations. If your B2 was 12 months ago, you should be OK with just the oil change.

LenniePaz

It says B3 is due for some reason. I'm the second owner and bought the vehicle with 24k on it. I got an A done at 30k then a B at 40k.

streborx

Since your B service at 40K, how much time has passed? If 12 months or less, then at 50K, you should be seeing an A3 service due. If more than 12 months, I'm not sure which indication might appear.
A and B services are fundamentally an oil change and an oil change and brake fluid change, respectively. If you did the B service at 40K 12 or fewer months ago, all you need now at 50K is an oil change. After resetting the service indicator, it should report something like "A service (or B service) due in 365 days".

LenniePaz

Aren't new plugs required at 50k? Also, ever since I bought the vehicle the A and B service reminders have been off.

streborx

That's why I said "A and B services are fundamentally ...."
Yes -- there are other services that are recommended at both A and B service intervals once you're past A1 and B1. At 50K, spark plug replacement should be done. MB no longer publishes a maintenance guideline booklet, but one of the last ones I've found is from 2016 (attached). This should give you some idea of what should have been done in the past and what should be done now.

W205C43PFL

Sorry about the late reply, looks like someone else were able to answer your question.

streborx

Just a bit more information about A and B service indications.
I DIY my A's and B's every 5K miles / 12 months, and I'm coming up at the end of this month (Sep) for my next service at ~23K miles / 60 months. This will be my 5th service, and the Assyst Plus is telling me "A3 Due in 28 Days".
I reset the service indicator at each service, and my indications have been:
5028 miles / 12 months -- A1
10014 miles / 22 months -- B1
14473 miles / 34 months -- A2
19086 miles / 48 months -- B2
~ 23000 miles / 60 months -- A3