I recently replace my battery and alternator (with last 2 months). Today my alternator/battery light came on, then my check engine and abs lights also came on. When I am able to get out of park into drive, it won't shift out of first gear. My heater, headlights, dome light, and power windows won't work. Can't use my turn signals. When I turn off the card and put the key into the accessories or on position, all my lights and everything works. What would cause this?

 

Could this issue be caused by a bad serpentine belt and/or Belt Tentsioner and/or Idle Pulley? It makes sense to me that the alternator couldn't put out enough power because one of these parts isn't allowing it to rotate fast enough, causing the computer to freak out and disable power-consuming devices to provide enough power from the alternator to charge the battery.

I am planning to replace my belt and see if this helps. If it does, I plan to replace the tensioner. I looked at it yesterday and it looked like it was wobbly. I have 160k miles on my car and I haven't replaced it. I may just replace the idle pulley as well.

 

Are you able to pull the codes? It'll give you a great place to start troubleshooting.


-Dmitry

 

The issue was my alternator, again. I replaced my coolant reservoir, due to the stem having a crack in it. During replacement, some of the coolant leaked onto the alternator and fried the voltage regulator. The alternator was still under warranty, so just the time to replace it.

Aqati

 

Excellent, glad that you got the issue sorted. Please let us know if there's anything else that we can help you with. I did not ask you what platform your C Class is (W203 or W204), so I've attached both sections of our DIY tech articles.

Mercedes-Benz C-Class W203 (2000-2007) Technical Articles

Mercedes-Benz W204 (2007-2014) Technical Articles



-Dmitry

 

this working thx!