ignition key won't turn

The ignition key won't turn in my 1999 E320.
The steering wheel turns freely.
I've replaced the batteries in the key, but it wouldn't turn before or after doing this.
don't know if the following is helpful. I replaced the engine battery a month ago and drove it since. Worked fine.

Thanks

 

As you have a long plastic key that chances are the wire has broken on the transponder coil and an easy fix normally

 

Do you have a second key to try with?
Incidentally you don't require batteries in the key for it to work in the ignition. It receives power through an internal the coil from the EIS.

 

Hi,

If the steering wheel is already unlocked then it could be a problem with your EIS. But try the key first.

Are you in the US?

Mark