Hello all I have a weird issue going on, we have a 2012 C250. The car runs beautifully, but now we can’t start it. I insert key and the car does nothing no dash lights, nothing. I replaced starter and nothing changed, I have tried jumping the starter through fuse box and nothing. I have no message saying “remove key” I’m stumped and don’t wanna do more without maybe getting some feedback on what you guys have experienced. Please help I have to get my daughters car up and running!! Steering wheel is not locked!

 

moved to W204 forum...

 

Do you have a scanner handy? Now its time to read fault codes from disrupted modules.

Usually EIS Module (Key sensor) is involved with poor internal connection to optical position sensors. This can be soldered internally or dealer/shop can code a new one.

Another thing you can do to expedite resolution clear troubles is simply to reboot the car: disconnect battery power for 15mn or longer (do not shortcircuit the + side to - side) - Just let it sit to help the SAM power controller regain sanity.

Lastly always ensure good battery voltage is available. Charge as needed. Marginal voltage conditions create disruptive opportunities where equation can be written as:
​Low Voltage + Poor Connections = marginal Luck.