New member - introduction and request for technical info

[Vic in Illinois]

Hello all. This is my first post.

This spring I purchased an '03 G35 coupe through Fb Marketplace. It was owned by a young guy & has a decent number of minor modifications. However, it was disclosed right in the listing that it had a problem with the throttle body & the motor would not really rev more than a few hundred RPM above idle. The price was right, the car looked good, and I've wanted one for a long time. I checked it out & it started right up, sounded good, and when I put it in drive or reverse it engaged smoothly and would move forward and back, but as the ad stated, it would not respond to the throttle pedal.

I'm not a mechanic, but have one that has done great work for me previously and he said it sounded like a puzzle he would enjoy solving, so I had the car flatbedded to him. He has a full-time job & has been working on it occasionally in his spare time, but it's been many months with next to no progress.

Here are the codes he told me he was getting: U1001 , P1122 , P1126 , P0031 , P0051

This was how he described what he was able to find searching those codes & his results:

Low voltage at the throttle body on the line that is power from the ECM to the throttle body.

OBD scanner reading powertrain control module says low voltage, but digital multi-meter says there IS power to it.

G35 throttle body voltage - (at JustAnswer.com)
He could see a partial answer showing something about grounding one pin out to bypass the ECM's control of it, but the rest is hidden behind a paywall.

He needs someone to tell him what the voltage &/or ground should be with the vehicle off & with it running, going through the ECM to the input plug at the throttle body.
He needs a wiring diagram/schematic of the throttle body plug-in
It could be a bad wire, but he doesn't think so.

Does anyone here have the wiring diagram/schematic of the throttle body plug-in that they can share with me to give to him?
Please let me know if you have had this issue and, if so, how you were able to resolve it. I welcome any suggestions even if you haven't had this exact problem.

I trust my mechanic/friend, but am almost desperate at this point. I bought the car 9 months ago and haven't been able to use it at all. The car is in Kankakee, IL, so if anyone here is in the area and thinks they could solve the problem, please reach out to me.

Thank you.

[VStar650CL]

There's a complete FSM for your ride here in in Nico. You can find the manuals here...
https://www.nicoclub.com/infiniti-service-manuals

...and here's a link to the engine control (EC) section specifically...
https://www.nicoclub.com/service-manual ... 3%2Fec.pdf

I'll evaluate your codes later today, I don't have time at the moment.

[VStar650CL]

Okay, as you surmised, your first task is to get the TB powered up. The U1001 may be from some modification to the car, the P0031/P0051 are heaters for the front O2's which the car can run without for now. The TB has a separate fuse and relay in the IPDM, that's the first thing to check. If the fuse is good (and check it with a test lamp, not a visual check), then try swapping the A/C relay with the Throttle Motor relay. If that all checks okay, post back and we'll go to the next thing.