I just got my g35 04 coupe. It's seems to be driving fine to me but I'm throwing these codes c1109 -battery voltage abnormal, u1000 - network communications circuit, p1815 - manufacture mode switch circuit, p0615 - starter relay circuit, p1273 - air fuel sensor 1 heater bank 1, p0327 - knock sensor 1 circuit low input (bank 1)

Anyone know where I should start?

 

Replace the knock sensor first. A knock sensor will set a code but will not turn light on. It will just make the car run a little sluggish. You next need to see what the freeze frame data shows for the U1000 code because there is a tsb for this code if the data matches what is in the bulletin guidelines. The C1109 in the abs system is due to low battery voltage which is common with a weak battery and will not throw a light on. The p0615 is due to the low battery voltage issue as well.

 

Thank you so much... Freeze frame for u1000?

 

Freeze frame is like a snapshot of your engine at the time that problem occurred. You need an OBD scanner or something similar to read it.