P1800 code where is the transmission control

I just went through this with my 2002 I35. The P0340 code is the Cam Shaft Position Sensor, Bank 1. it is a sensor that is located near the firewall of the car on the drivers side of the engine. I just replaced my bank 2 sensor (error code P0345) today, pretty easy fix to be honest. I have never replaced the bank 1 sensor. I went against all of the infinity/Nissan message board advice and bought an aftermarket part at O'rielly for about $65. You may have already found the information, but there is a lot of chatter out there about this problem. I replaced my sensor and my car is now back to normal. I guess I'll see how long the aftermarket sensor lasts. Good luck.