tivoboy

Backstory… rock solid car, but hasn’t seen more than about 1000 miles in the past 4-5 years. 22.5K miles.

Been doing a bit more driving lately, but today just parked it in a garage and it would NOT DRIVE or REVERSE.. it seemed to go into R or D in the display, and felt like the transmission was engaging.. Gas made the car at least move VERY slightly rewards or forwards, but then nothing.. felt like BRAKES on, but car not moving.

No tranny issues present up to this moment. Car has been solid, and maintained, although last head to toe service was 4 years and 1200 miles ago. (I was going with a bit more mileage than years as the yardstick).

Garaged always in FLAT garage, but only difference in the past two months has been parking on a driveway that has a small slope. So, MORE engaging of parking brake than normal.

I could get the car into N for towing. Tried putting it into P and rocking, E brake on, E brake OFF - makes noise like full dis-engagement, and of course in N it rolls fine.

VERY odd, but where should one start to look for random failures that can lead to this?

W205C43PFL

First of all, a 2016 model year vehicle in 2024, the transmission fluid should had been done if not it is overdue. It is both mileage and time based. Secondly, did you get a scanner capable of reading Mercedes codes to see what the car computer is reporting back?

tivoboy

Thanks… I did transmission fluid changes about 5 years ago just before he pandemic… car was still under warranty (7 year) at the time, but figured I’d do that when I did B service..

Haven’t gotten scanner codes back from local Benz stealership.. My favorite local shop apparently closed two years ago.. ;-(.. I hoping that the $310 diagnostic charge will yield some insight of course, but can’t figure out what the stack rank of probabilities is for something to go from seemingly fully functioning to catastrophic failure in a heartbeat.

W205C43PFL

You're welcome.

Might be the aux battery, check the starter battery as well, how old is it? MBs are very sensitive to voltage changes so a weak battery could cause issues like this. If you don't want to pay for diagnostic charge, you could get a scanner, forum members here are recommending Launch CReader Elite Benz V2.0. it is cheaper than one diagnostic charge at a shop.

Especially if you plan on keeping the vehicle for a while, it is worth having a scanner.