Hey guys recently upgraded to an 04 G35 after my 03 got wrecked. Bought it about a week ago. When I bought it the Key Fob didn't work. Bought new battery for it and nothing. So I've just been unlocking the car with the key. During this time the anti-theft light on the dash has been off. This morning however when I got in the car the Anti-Theft light started flashing and when I went to start the car it just started clicking and not turning over. Would this be the anti-theft disabling the car or is it just my starter that went bad?

Thanks for any help!

Have you ever started the car with this key? The key is chipped and if it is not programmed to the car, it will do this. How many original keys do you think you have?

These are keys I was given when I bought the car.
I've been using the one on the right to start the car since I bought it.

Your Nats security will only cut the ignition signal. No matter what your car should try to turn over. Check your starter, battery, battery cables for the problem.

Ok, the physical keys are likely original looking at the pictures. The chips are embedded in the body of the key itself.

The button fobs won't have anything to do with the car not starting, so let's disregard those (they are also easy to reprogram).

I think there are several topics on the matter about diagnosing why the BCM (body control module) loses or doesn't recognize a previously programmed key. My direct knowledge on the matter is from an RX-8 I owned recently, but nothing specific to the G. Best to search for keywords as I mentioned because I don't want to point you in the wrong direction.

I've got a just in case key that was cut but not programmed for my 2004. If I try starting the car with it, you can turn the ignition switch but that's it, it won't try to turn over the engine.

Yea I was thinking more the starter. I've had it go out in my older g35 and it was the same signs. What threw me off was the anti-theft light flashing now when it wasn't before. So I wasn't sure if the anti-theft disabling has the same signs.

So it is a possibility that it is the Anti-theft disabling it and not the starter that's gone bad from your experience?

Start with checking the starter, battery, ground, and connection points first. No, I don't have experience with that in my G, my memory is getting cloudy from my recent dealings with an RX-8.

Like I said the Nats security only kills the ignition signal. The car will turn over but won't start because the coil packs won't have signal if the Nats doesn't see a registered key. The car should always turn over unless there is a starter issue, bad clutch position switch, bad PNP auto trans switch, bad battery, bad battery cable, etc...

Alright I'll check those out when I get home again. Hopefully it's something simple then and not having to change out that starter lol.
Thanks for the help!

5 failed attempts to start the vehicle with NATS interlock will disengage the starting relay and the engine will not even crank.

The reset I think is to turn the ignition to ON 5 seconds, OFF 5 seconds, and repeat that for 5 total cycles. Not 100% sure if it's 5 total times though I would need to check the FSM.

Reset is done with good key obviously.

Yea the car never even tried to crank when I tried to start it. Just the repeated clicking noise like the starter was out. I just wasnt sure because the anti-theft light was also blinking during that time and it hasn't been blinking prior to this. I tried the Anti-Theft reset trick earlier but nothing came from it.

Ok the clicking sound is the solenoid chattering due to insufficient amperage, your battery is dead probably.

EDIT: Possibly a dirty connection on the electrical system, possibly a failing cable (inspect the entire length for abrasions, holes, cuts, replace if it shows ANY damage), possibly a failing starter (pull and bench test).

Hey thanks everyone for the suggestions. I was able to test my battery out when I got home and looked like it was low amperage on it. Put it on my charger for an hour and issue resolved. Thank goodness it was that. Now just need to figure out if something is draining it or if it's the age of the battery lol