[SFmbzE320]

I have all the three keys: Key Fob, Valet Key, and Flat(Master) key.

I can open all the doors, the trunk, the glove. The dome interior lights come on. The headlights are fine. Radio comes on.

However, when I insert any key into Ignition to turn to Position 1 or 2, it just does NOT budge from Position 0. I tried using the Flat(Master) key, push back n forth like many times but still no luck. I sprayed lubricant into the keyhole and tried several times. Nothing.

The switch blade key in the Key Fob and the valet key shows a little bit of wear but the Flat (Master) key looks fine.

Please provide any tips to resolve this key issue without having to tow the car to the local MB stealership. Other than that, the car runs pretty smoothly, was running smoothly until this happened. Thanks.

 

[Kajtek1]

You have blade key with bad tumbler?
That is pretty s**ty situation as you can read in the topic in stickies. With some help of WD40 and vibrators members usually get the key to turn as this is required for tumbler replacement without kicking the blockade into permanent lock and associated expenses.
I consider that highly advanced DIY job, so not for everybody. If you have good relation with dealer you can ask them for quote on tumbler replacement.