Long story short...last month I ordered a new "smart key" along with a new blade/insert for my E300. The smart key worked fine but I never tested the insert, until yesterday. Sometimes I leave the car running with the smart key in the ignition and use the blade/insert to lock the car if I am running into a store to do a quick errand which is what I did yesterday...well, low and behold, the insert succesfully locked the doors but then absolutely refused to unlock them.

So, I called my wife who came with our other smart key (lucky I was only 10 minutes from home)...now the problem is that the other smart key will not open the doors remotely if the engine is running...which it was, so my only hope was that the insert in that key would unlock the doors...which luckily it did.

When I got home I tested the other 3 inserts I had from the other old smart keys and every one of them worked to lock and unlock the doors...but the new one still failed to unlock...so don't take for granted that your insert will bail you out when the remote door opener fails you...test yours now!

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz