To amplify on Jeff's comment, figure every two years for brake fluid replacement. Coolant can be anywhere between five years on older cars to fifteen for newer ones, though that last figure makes me a little nervous. Power steering fluid ought to be changed after ten years or so, too. The serpentine belt will be checked at every service, and when it begins to show signs of cracking it's time to replace it. There's no specific mileage or time frame for that.
So an A Service is an oil & filter change along with a bunch of inspections, and the service advisor will come back with the tech's recommendations, if any. I had my C230 in for an A Service yesterday, and a few items were flagged as "Cautions" meaning they could use attention soon. In my case, I'll do the air filter myself, and schedule most of the rest before winter comes. And feel free to take what they recommend with a grain of salt. They recommended a $200 fuel injection service for mine, but unless the car is running rough or gets poor mileage that's pure profit for them--and frankly, dumping a bottle of Techron concentrate in the tank a few times a year is much cheaper. My tires are at 6/32" too, but at 3,000 miles a year on that car they'll last another year at least and Michelins are always attractively priced at Costco.
Tranny partial ATF and filter+plug change done in 2013. Air filter last year.
I replaced battery, brake fluid and oil/filter this year. It had shown A but I wanted to do brake and battery.
After getting car back it said D due next on the display.
I queried this with the SA and he said it needed the timing chain done next year (or as soon as possible).
Does the D signify the chain or maybe brake pads? As you say jbanks...clear as mud heh!
I didn't manage to get a print out of the diagnostics carried out. Do dealers hand those over? (I did get one from an indy before)