yup the infinitis do auto lock if the door is not opened for a few seconds and i believe that the timer can be set from the settings but i cant remember for sure

 

By the way, I was working on both the cars this past weekend and decided I would just take the one key fob. Well it certainly does lock/unlock both cars but unfortunately it only starts one of the cars and not the other. So apparently, the lock/unlock code is separate from the engine start code.I guess that's a good thing because at least it is secure from a starting and driving off perspective.

 

Interesting ... if the ikey in question was paired to both cars, it should have been able to open and start both cars.