NATS Issues? Dealership time?
 

I got off work and when I got home realized I needed something at the store. I hop back into my 05 G35 Coupe and the engine only turns over it won't crank. I see my security light is solid red so I guess it's the immobilizer.
Symptoms: Car turns over but will not crank, security light stays solid when key is inserted, engine fans turn on when key is in the on position, ECU not recognized by car

Things I've tried:
Tried resetting via battery removal and pumping breaks,locking doors and turning key on/off in various instructed ways, etc
Unlocked door with key
Replaced battery
Replaced fuses
Replaced Relays
Had pop-a-lock try to reprogram key but their machine fails to recognize my car
Tried reprogramming with Uprev (searching for ECU)

I'm guessing will need to tow it to the dealership unless somebody can help me. This is a pain! thanks guys!

Hmm...I've had a similiar problem. I've replaced the battery, cleaned my terminals many times. New ground wires, etc. The weird thing was, it ended up being my alternator. The signs don't show right away. It got to a point where my car needed a jump start to get going. Seemed logical it was the battery. The battery drained itself so much and the alternator wasn't charging. I replaced the alternator and the problem was fixed.

The same thing happened 2 months later. This time I was driving and losing power. I couldn't go over 5mph an hour. All dash lights would light up and I got the solid red light as well. Then I'd turn it off, restart the engine and it seemed fine for a few mintues. Started driving again, and power would go away. Turn off the car for 10 seconds and turn it back on like normal. Had no issues with power, battery seemed fine. Stereo, everything, etc worked. Turns out, it was my brand new alternator that went bad. A new one is getting installed in 2 days from now. Its very strange. I think when ground cables are bad, or when there is a link point in the electrical system like a battery or alternator...our cars do weird things. I think it has something to do with how our cars manage electricity. Its distributed in a unique way. When I was in the dark about my alternator the first time, I had weird stuff going on. Always need a jump to start my car, which is normally batter related. Then I had LEDS that went out on my tail lights. Once everything was fixed the first time, all things went back to normal. All LEDs are working now. Very strange. I'd get your battery and alternator rechecked multiple days in a row even if they are new. Also, make sure your ground wires are good. They get corroded. The stock terminals are also angled differently than typcial battery posts. It requires a very tight lockdown if using aftermarket batteries. Hope this helps.

I haven't thought about the alternator but my car quit working suddenly. I had no warning signs it was running as good as it ever did. I will get that checked

If you're intention is to take it to the dealership make it Nissan, parts and service are 30% less than Infiniti. Or if you know a qualified independent shop they'll get you back on the road....Gary

If it turns out to be a BCM issue or immobilizer issue will the Nissan shop be able to fix or reprogram the computer like I've seen some need on here? Nissan shop is 45 miles away and Infiniti shop is 75 miles away in the opposite direction. I live in the sticks.

Nissan's Z is what we drive plus a back seat, they have all the ability to work on our cars that Infiniti does and in my opinion there mechanics are better trained....which I've mentioned before! I used to live in the sticks until my valley grew up....sadly!
Gary

Try this from the service manual.

ESCAPE FROM LOCK MODE

1. Turn ignition switch OFF.
2. Turn ignition switch ON with registered key. (Do not start engine.) Wait 5 seconds.
3. Return the key to OFF position. Wait 5 seconds.
4. Repeat steps 2 and 3 twice (total of three cycles).
5. Start the engine.
Does engine start?
Yes >> System is OK (Now system is escaped from “LOCK MODE”).
No >> GO TO 3.

I wish this worked. I've tried it 100 times and just went out and tried it some more. When I lock the doors the security lights stays solid when I unlock the doors it flashes. When I turn the key it stays solid and it will not let the car crank when turning it all the way.

I can almost guarantee that its not the alternator, your car will start, run and drive just fine without one until your battery dies. I would almost bet that its a NATS malfunction where either it stopped recognizing your key for some reason or the immobilizer just F'd up and won't let you start the car.

I've had this happen to a couple guys I know, we just reflashed the ecu with Uprev and disabled NATS completely. Lets you use unprogrammed keys as well (dealer wants like $200 just to reprogram a key)

$300 for a flash license and considering you get the benefits of the tune as well its a win IMO. PM me if you want to give it a try, you can do it from the comfort of your own home, no need to tow anywhere

I'm not opposed to trying this but if it didn't take/fix my car would it be possible for a refund? My wife would kill me if I did this and it did not work. Also CEL is not on and it won't do an ECU reset with the pedals. The CEL light never comes on. Is that consistent with a NATS problem?

Here's the thing.....my car still started are few times, but I couldn't go anywhere. Eventually the power ran down a bit and it wouldn't start anymore. Then a couple hours later I got a jumpstart after taking it off the tow truck. I ran it for maybe 2 mins or so. I parked my car and came back to my parked vehicle the next morning. The car started right up with no problems. This is after it wouldn't start the day previous. I pulled into the garage and checked the battery and alternator. Alternator is completely dead, not charging. A few days prior it was fine though. Its a bit misleading since everything seemed to be ok with my car starting and driving normally. Its possible my alternator was working intermitently.

With this issue, I got the solid red immoblizer light as well. It did some strange things when my alternator was bad. Also, try sitting in the car and locking the doors. The red light should still be on. Sit there until the light goes away. I want to say it takes like 30 seconds or so. If you are at 2 mins, then obviously something is not resetting. If it starts to flash, then unlock your doors. Open it as well, and close it, just like you would as if you were getting in the car. See if that helps.

Alternator was my problem the first time. My second one is getting installed tomorrow, since the signs are the same as the first time. If it doesn't fix it...then it could be another issue for me as well. I'm confident it will go away though. I just got a bad alternator the first time around.

Keep us informed as to what happens.

Your symptoms seem different than the OP's

the CEL isn't 100%, and yes if it doesn't work you can get a full refund. Worth a try. I'll PM you details

Sounds like I don't have anything to lose trying this then, PM me and we'll get it started. Thanks!

Well the Uprev reflash did not work, I updated my symptoms, I guess its time to bite the bullet and take it to the dealership.