My c240 key wasn't turning now does! (who knows why)drove car home ran ok. Started car in garage just to see if key would turn after starting when I put it in gear it chugs a couple times then stalls. Ive tried starting it letting it warm up and still stalls when i put it in gear. I sometimes get a battery/alternator message when it stalls but not every time. I checked battery voltage in car, car said 12.6 and 14.4 running. The battery is 1 1/2 years old and alternator about same. Any ideas before i take it to a mechanic?

 

If your getting the battery/alternator msg then the alternator is the issue or the voltage regulator which was in my case.

 

I don't get message every time (but most) and goes out after car stalls.

 

Yeah same happened here until one time i was on the highway and my car electronics just shut down and was stuck in first gear then i got the battery/alternator message. Checked the alternator and it gave normal voltage but i didn't buy it i knew something was wrong with the alternator so i took it off and first thing i did i replaced the voltage regulator and the problem went away saved me couple of hundred $. That was around 3 yrs ago.

 

Would voltage read normal on screen in car? like 12.2 and 14.4 when running and still be bad?