I had to have mine replaced, but it was at the fault of the dealer or smart or whoever coupled the keys! I ended up with someone else's key. It took 4 1/2 hours to program, because smart didn't want to give up the program codes. I was told if it had been my fault a new key with the fob with electronics is $120 and the key without electronics is "only" $80. Good luck! I only had to wait about 2 weeks!
I still haven't figured out how to lock myself out of my car, but my hubby wanted his own key!