Ok so my g35 went into limp mode and it pulled these codes. But I've searched and read that sometimes changing the throttle body and app sensor won't fix the solution. Where can I start to fix this solution? How can I test the TB or APP sensor to see if they are faulty?

Video

 

P1228 throttle closed position learning needs to be completed. See section EC - Engine Controls of the FSM, pages 75-80 somewhere in the basic service section for steps on doing that.

P2122 APP (pedal, not throttle body) sensor 1 low voltage, there's a dual rheostat switch inside the pedal, one side of the switch probably failed, replace with a new switch. You can buy them on the internet for around $15 rather than buying an entire pedal assembly for $150.

P2138 APP switch 1 and switch 2 are sending different values outside of expected range, basically the ECM is saying that one of the switches has failed inside the APP.

Out of curiousity did these problems happen out of the blue and did they both happen at the same time? I have the feeling that sometime during your troubleshooting you unplugged the throttle position sensor on the ENGINE which then caused the code P1228 even though the problem was always with the GAS PEDAL (APP switch).

Any time you unplug the throttle position sensor while the battery is still connected then the ECM needs to relearn it's position via the throttle valve closed position recalibration steps in the FSM. You will also need to perform the accelerator pedal release position recalibration which is in that same section but wait until you put in a new pedal switch.

For the future, don't unplug any sensors while the battery is connected to the vehicle. You can cause some pretty serious problems by randomly unplugging powered sensors. The only exception to that would be unplugging a coil pack to determine which cylinder is misfiring and even then you would be doing so knowing that it could damage the coil but that's how you hunt for a misfire so...

https://www.nicoclub.com/archives/in...e-manuals.html

EDIT:
MAF - Mass Air Flow
APP - Accelerator Pedal Position
FSM - Factory Service Manual
ECM - Engine Control Module

 

Ok I'll do what u suggested and yes these problems came out of the blue. At first they came a while back around the beginning of December so I just left it in my garage until I had time to look into it. And then I disconnected the battery one day and the codes were gone and it was running perfect and then one day I got a misfire code and I went ahead and did a spark plug change and before disconnecting coil sensor I disconnected battery because I didn't want to short anything out but after doing the spark plug Change misfire went away and now the limp mode came back like 2 weeks after changing spark plugs? But the first time it went into limp mode it was out of the blue. And it's throwing the same codes as last time.

 

I'd start by ordering a new APP switch, it's an easy replacement, then do the recalibration steps in the FSM for APP closed and throttle closed. If you need it running today you're probably just going to have to buy a whole new pedal assembly since that's what the local parts houses will have stocked. It's a common item and used on a LOT of Nissan's so they'll likely have one in stock.

 

I dont need it today so I'll just go ahead and buy the switch you mentioned. But if it's not that then where could I look at next?

 

Is this the switch?

 

Yep, and in this picture you can see where it mounts on the pedal assembly.

 

Ok so i changed the app sensor and it was fine for like a week and now it's doing limp mode again. Now the only code that it throws is P1229 and it throws it twice.

 

Did you mean P1226, you have to perform the throttle closed recalibration to clear that code.

Open the hood so you can HEAR the throttle motor, don't touch the accelerator pedal, turn ignition to ON, turn ignition OFF, within 10 seconds you will hear the throttle valve move. Recalibration is complete after 10 seconds.

This needs to be done anytime the throttle body harness is unplugged.

EDIT: Section EC - Engine Controls of the FSM. Under "basic service procedues".

 

Oh shoot I didn't think of that???♂all I did was the idle relearn because I ended up cleaning the throttle body. But I'll do that as soon as I get a chance!