artythekid

Hi all. I have a 2011 c300 4matic sport (w204) Recently I had a problem with the car. the car died and I had it towed to my house. it starts with a jump but when I pulled the cables off it would die. I had a battery tested by autozone and they told me the battery was no good. I bought a new battery and the car started and was working normally. I drove the car for about 2 days with no problems and on my way home from work every light in my dashboard came up. ABS, license place light was out, srs malfunciton and all sorts of other lights. the car died with the error messege srs malfunction service required. I waited about 10 minutes and went back outside. all my lights are gone the car almost started but then died and now my battery is dead. could it possibly be the alternator even though I been driving the car for 2 days without any problems? or do you guys think this could be another issue? where should i start looking?

NZ-Merc

Hi,
Sounds exactly like the alternator is not charging for some reason.
First you need to fully charge the battery then you need to test the alternator for charging.
Usually this is done by comparing the non running battery voltage ie 12.8V with the running voltage 13.8- 14.5v which would indicate all is well.
With yours I suspect you will find like 12.8V non running and when running 12.5 or something like this, then the alternator would most likely need replacing.

There is a menu on the dash which can display battery voltage, I am not familiar of what menu is required to display this.

Either way fully recharge the battery first that will point you in the right direction.