CLK430 ignition key won't turn
 

Neither one of my electronic ignition keys for my 2003 CLK430 will turn in the ignition. This is a sudden problem with no issues prior to this evening. Any suggestions what has happened and what can be down to fix the problem?

Check the voltage on the vehicle battery. If it's low, the ignition switch may not work. Also, you have a W208 (I assume you have a cabriolet - the MY2003 CLK cab was a W208 carryover) so you might want to check that forum.

Mworthy did you ever find a solution?

fI had the same thing happen to me a few days ago out of nowhere. I checked the battery voltage, fuses all in working order. After hours of youtube vids, I saw a few that gave possible key fob "adjustments", particularly the infrared IF beam and how to readjust it so it will line up with the IF sensor in the ignition which allows your key to turn. I took the circuit board out of my fob, and cleaned the indide of the infrared glass on the tip. Replaced it in the fob and it started up like nothing happened. It did trigger BAS, ABS WARNING NOTIFICATIONS, WHICH I RESET BY TURNING THE STEERING WHEEL ALL THE WAY LEFT, THEN ALL THE WAY RIGHT WITH THE ENGINE OFF AND KEY IN POSITION 2. Disregard the all caps, was accidental and not yelling. So far no problems and from what I hear, I have avoided some costly repairs by doing this.

Same issue again
 

The key wont turn in the ignition again!!!! We had the shop replace the key, the ignition switch , and the steering lock box.It lasted 2 weeks and now the key wont turn and the lock does not disengage.They checked all the circuits and no idea why its gone again. ANY ONE have any ideas???????

did you ever get his resolved? I am experiencing the same issues