Hi I got a 06 G35 coupe that will crank but not start. I got the car like this, previous owner tried to remove an aftermarket security system and didn't do it well. I removed the aftermarket system and join the wire that is needed to crank the car (this harness had some wires joined that weren't supposed to be. Its a white connector a bigger brown one near the brake paddle ). The ecu 15a fuse behind battery was blown as well as the dash fuse inside the cabin, but still no luck the check engine light is not on when I turn the key and obd will not connect . So I check for power to the ecu (with it unplugged) , I am getting power to pin 121 and no power at 119-120 which is should when I turn on the ignition. I do get ignition power to pin 2 however . I have another used ecu on the way (cheap enough to give it a try) just in case it is at fault. Any help would be greatly appreciated .

^^^

INFINITI vehicle immobilizer system

http://www.infiguide.com/infodata-1333.html

You may want to obtain the FSM for your vehicle for more detail.

Telcoman

I have the FMS .Ya I was thinking it was the immobilizer too but there was no power to the ecu not even the check engine light was on which led me to think there was a bad fuse, relay or a short in the wiring I checked everything twice couldn't fined anything. I Got another ecu and now the check engine light comes on and I can here a lot more relays clicking and what not, have't tried starting it yet waiting to program my key. Also took apart my old ecu and looks like the L9762 chip (something to do with power supply) had 4 pins with scorch marks .I might try fixing it later as a back up but I don't like micro soldering and probably will have to change out fuses and resistors . I'll probably know this weekend if it'll start. Thanks

Ecu and key programming fixed it ! Now I gotta figure out why the drivers side fan stays on all time time even though the car is off. the coolant temp sensor seems to be working .