My '07 Nissan Frontier has a does not recognise key code

Thank you, we tried that and no luck. What happened, we took the truck to a reputable mechanic and the replaced all the coils. When it came back it worked great for 2 weeks and then died. We noticed that the negative battery cable was not tightened down on the terminal and we haven't been able to start it since.

Battery is good.

No, the coils didn't. But when the truck was in the shop to have the coils replaced, wouldn't they have disconnected the negative battery cable and then they didn't tighten it back down and whatever happened was because of a loose battery connection?

Over $1200.