Boosted G35-Just replaced transmission-Won't Start
 

2005 G35 Coupe Auto trans. Okay, need some help here. Having some issues getting the car started after putting a new transmission in. The starter and battery are fine (both tested). When I go to crank it, nothing happens, no clicks or anything so its something electrical. When I hook my code reader up to it, it shows "P" for a few seconds while the relays or fuses are clicking in the IPDM fuse box near the battery. I have pulled my headlight relays(since I know they work) and put them in the ignition and starter relay spots. Still doesn't work. Also the throttle body hums very loud when the ignition is on, is this normal? I put a new throttle body on also. I have a video of when "P" comes on when the code reader is reading and the clicking of the relays.

auto or manual?

Auto trans.

Update: Reverse lights won't come up when put in reverse. I checked tail lamp fuses and AT cont fuse. All good and I replaced them. I think the problem lies within the tail lights wiring/fuse?

Since you did transmission work and suspect electrical problems, have you RE-checked all of the wiring harness connections? Is it a new or used transmission? Were/are all of the switches good in the transmission? The issue sounds to originate from a neutral safety switch, but I could be missing something or just wrong.

Used trans. I have checked all connections and all wiring and connections worked previously. All are firmly seated. I did valve body work on it also, so I am thinking possibly that the park/neutral sensor that goes to the TCM could be on wrong inside but it's unlikely.

Where is this neutral sensor your talking about?

Do you have a the FSM for the vehicle? You can read the following thread if not. The information is in the Automatic Transmission section. Page 250 of that section deals with that issue. I would do a search within that section of the PNP (Park Neutral Position) Switch. It appears to be within the transmission valve body, but I'm not a transmission guru. the FSM states something like checking P and N to start. If not starting, try D and R, but I would recommend just a tap on the starter to see if there is anything getting there, not a full-out starting it. Diagnose, not run the car through the wall.

Also does the dash reflect the shifter position?

https://g35driver.com/forums/g-spot/...nuals-fsm.html

Yeah I'm guessing the PNP is what I will have to check next. "P" does not pop up. No other gear works to start the car either, I've tried em all. Starter is fine and has been tested.