Hey good day please I need help very frustrated I removed my battery from my Infiniti G35x to start another car because the other car battery was weak after i started the car I then returned the battery to my Infiniti I then tried to start the car it cranks but it refused to start. I used the car this morning am so frustrated I don't know what to do I noticed that that the security light stays solid on if I turn the ignition to on is this supposed to be normal or is it a security problem because I tried locking the door with the remote then unlocked it then tried again to start the car it cranks but doesn't start I also detached the key from the remote I put it in the ignition but it doesn't turn the ignition but if I use the remote it turns the ignition please am so frustrated I need help.thanks

 

Solid red light WHEN CRANKING THE ENGINE means the car does not recognize the key you are using to start the vehicle. The engine will crank but the injectors will not open and there won't be spark, it's a NATS/IVIS interlock, the anti-theft stuff on the G35.

First try unplugging/reconnecting the battery, if that doesn't work then try resetting NATS by following these steps from the FSM.

 

If that doesn't work you'll probably need to get the BCM reprogrammed to accept the keys by a locksmith or the dealership.

 

If the key light stays on it can be a couple things. Probably need to have a scan tool capable of resetting the BCM codes first. You also may try putting your FOB in the slot located in the lower dash where your left knee is at and try to start.

 

OP needs to verify but I was under the impression that he didn't have an intelligent start (push button) system.