Friends g37
 

I was watching my friends g37, for a couple of days and when I was driving it the no key light popped up. (Every time I started the car it pops up, and always had problems locking/unlocking my car. I have to put the key directly next to the door to unlock it) then it happened again and the car just shut off then it wouldn't turn on, after trying and trying, I got it to turn on and the service engine light came on. I drove a little more than all the lights shut off[headlights, dash, center console] then the engine turned off so when I got it back on again the lights stayed off and said there was no key but I was able to get it back to home. The car is a 08 g37, and he just put a new battery in the key fob. Any ideas are appreciated.

Have you tried the other fob?

Perhaps the new Fob battery was old as well? I say go buy a new one. Maybe it sat on the shelf too long....also, did he take off the small plastic sheet that's on the battery? Its hard to see that and if you take it out of the package and don't look, you can leave it on accidentally.

The car itself may need a new battery.

So you guys are saying if I leave my car ON at the gas station and walk away from it, it will shut off on its own when the fob is an appropriate distance from it?

If the car will crank normally, then the car battery is probably OK.

Does the G37 have a "fobgina"? If so, insert the fob and, if the car starts normally, then the fob battery is low. If it doesn't start reliably, then the fob (or immobilization system) may be bad.
If no fobgina, then I'd replace the battery because racecar - they're cheap. Get a major brand and check the date on the package. If that doesn't work, then I would suspect a bad fob (or immobilization system).

The car will RUN when the fob is out of range but, IIRC, it will not stay ON if the fob is out of range (and possibly no input to any of the control systems). You can verify with the Owner's Manual or FSM.

Replace the battery in the fob first as suggested...$5. It worked for me. I was quoted $300 for a new fob and programing!

Assuming the fob, fob battery, and the car battery are good, then the problem has to be whatever it is that senses the presence of the fob. I'm not sure what the technical name is, but does that make sense?

Thanks for all the replies, it's still acting up. I don't know if this helps but he said the first time it happened was when I left my keys in the car overnight so it kept saying press break to start car. & after it said there was no key or something similar.