Hello guys am new here am looking for help, i got this mercedes w212 with 2.0 litre turboi4 engine which has a no communication with my engine management electronic and transmission and a loud fan goes on as i just unlock the doors and when its switched on, i have tried but i don't know what may be the problem, i will appreciate your idea.thank you

 

OMG, you sure got a plate full with this one!
Things don't just die without any historical reasons.
You say "you have tried... : tried what?

When/How did that start?

What sort of service records?

How are the batteries charge level ?

You know you need ignition ON to power up ECU, right. (Fan spinning is an indication ECU maybe on vacations...) - Go ahead unplug the fan until you can get the engine running.

What faults are other modules reporting ??

 

Exact engine model with 3 digits after main number you must inform others if you want to get assistance. Example : M276.xxx