Thanks guys. Yeah realtor I know how you feel when you can't turn the car off. Started thinking about all the ways to stall the engine, or let it run dry.....Anyways I will see what the dealership says. They'd better cover this.

 

Sorry for bringing up an old thread but I hated how no one posted the solution for this, so I wanted to when I found it.

For me the car wouldn't turn off even with the key removed because the fog lights were on. Many of us keep the fog lights on with the headlights so at first I also thought it was because of the headlights. KPierson lead me on the right track. The problem turned out to be a blown fuse on the IPDM located in the engine bay.

I hope this might help someone else.

 

Now this is a really old thread. My wifes G35 coupe did this today where it would keep running without the key until the lights were turned from auto to off. Very repeatable. If the lights are in any position other than auto the car will turn off normally. Also an american car impored into Canada just like the OP. Really strange. I'll post the solution if I find it.

 

I would definitely investigate the IPDM and key switch circuit. Something isn't breaking contact so the ECM thinks the ignition is still turned on.