I have a infiniti g35 coupe 03, and i got these 2 codes pop up, p1614 and p1615, they recently showed up, the car runs fine and all, starts up fine, what could this mean? (I also got a new key to see if it was related to a faulty key, but same results)

 

That's a NATS malfunction, usually get those together with the car not starting. If you've been Uprev tuned or want to get Uprev tuned we can completely disable NATS as part of the tune

 

Both those codes are the car saying "we don't recognize your key RFID signal".

There is an RFID chip in the key, when you turn the ignition on the BCM reads the key, if that key RFID code is the one stored in the BCM then it will allow you to start the engine, otherwise the engine will just crank but you will not get fuel/spark.

After numerous failed attempt it will enable the vehicle immobilizer and also throw code P1610, at that point the engine will not even crank.

You cannot just have a new key cut, you also need to have the BCM programmed to accept the new key RFID chip. Some independent locksmiths can do the programming, the dealership is another option, as is the UpRev tune NATS disable that Seymore mentioned.

Since your car is still running it means the problem is intermittent, usually a sign of a weak RFID chip, they have an integral battery that is non-replaceable and usually the lifespan is 10-20 years. Your 2003 is now 18 years old so it's likely the chip losing power.

You need to get this fixed ASAP before it dies completely because it WILL leave you stranded unable to start your car eventually.

 

If you want to get an Uprev tune we can preventatively disable NATS as well.

 

Excuse the side note - I'm pretty sure the NATS rfid chips in our mechanical ignition keys (for example) are "passive" as in they don't have their own power supply. The car uses a coil kind of like a Qi-charger for phones - to generate a responding code from these tiny embedded chips. Active rfid tags are larger and more expensive.
Not helpful info here, but interesting...

Hopefully the OP can jog his BCM's memory by reprogramming it to recognize his chips.

 

Yep you're right about the passive RFID, I should have known because of the range associated with the key but I have always mistakenly thought they were a semi-passive RFID since they don't just last basically... forever, like a normal passive RFID chip usually does.

 

Tirns put the faulty battery made those 2 codes be thrown, now the car is at 100% thank you all for your help