Had some issues with the B back in March / April. I'll try and condense it.
Parked and connected to a public charger I've used many times before and pushed extended range (free juice, why not) headed into movies with family.
Come out of movies, malfunction warning on dash LCD screen. Didn't take a picture of exact message. Turn key, won't power up. Accessories come on, but it won't "start". Battery is something close to 100% but didn't hit 100 nor complete the extended range part of the charge. After removing the key and retrying couple dozen times it powers up just before I'm ready to push the roadside assistance button. Drove it home about 3 miles, seems normal but warning on dash remains. Visit workshop.
Drove it next day (Sunday) around town, drove and charged normally. All sorts of warnings, malfunction, visit workshop, do not restart.
Called dealer Monday and dropped off Tuesday. Given C300 loaner.
Days go by, I get an update that they have a case open with engineering in Germany for guidance. No obvious cause for the multiple stored codes. Maybe have to replace the battery, no idea really.
We get well aquatinted with the C300 loaner and gas pumps for 13 days.
Got call to pick up the car, Germany considers the car fixed. Nothing was replaced, just various tests, resets, re-flashes, code updates, discharge and recharge. They found leaking left and right front axle seals and replaced them during this visit.
12 days later, "without restarting engine again, consult workshop" that one I have a picture of. Car is driving and charging fine. Called service department, no loaners available for couple days. So we keep on using it, next day different service advisor calls and says bring it in I'll find you a loaner. They take a brand new C300 off the lot and give it to us with a dealer plate.
21 days later we get it back. The report on the paperwork says they throughly checked the battery heater and charger and were directed by engineering in Germany to replace the charger.
Been driving it daily since May 4th, all good. Am I certain it is fixed, no. Here is why. These issues started in colder weather and it was returned in warmer. If there is an issue with the battery heater we won't know for months now. It won't be cold enough to kick the battery heater on until October at best here in CT.
Dealer did everything they could, they have only sold a couple of these cars and seems like anything beyond regular maintenance gets a case opened in Germany.
The only thing I ever noticed that was odd and this could be nothing is that we had the recall campaign for loss of power while driving performed in January, and since that update the E-Cell gauge would sometimes not come all the way up in cold weather and sometimes the needle would bounce around a bit on drive where you started cold, not from the garage. Could be nothing, who knows.
Dealer and I are talking about "compensation" now, they had the car over 30 days. Hopefully we get a lease payment comp or something on that order.