Problems starting

[Fozzieboy73]

Help please, my Merc E350 blue efficiency diesel estate won't start first thing in the morning. I insert the key, wait for glow plug to go out and turn the key but nothing. Turn key off (but don't remove) then turn on and it fires up. Throughout the rest of the day no problems starting. Any ideas please ???

 

[fabes]

Have you any error messages on the dash?

Can you read the codes via OBD2.
It could be an immobiliser or key b-issue perhaps, but read or get read any codes is my advice