Hey guys. I recently swapped my 2003 350z motor. I bought a jdm engine DE. I had to swap the entire engine harness since the jdm is different. I also swapped the injectors, fuel rail, starter, power steering pump, alternator, and throttle body (all these came from the old engine which work). I also changed coils and spark plugs. The car turns on, but I get only 2 codes which are the p2122 and p2127 which are the Throttle/pedal position sensor circuit high. I originally had the jdm throttle body which I ended up replacing because I thought that could be causing the issue. I also tired the throttle relearn procedure but my throttle body doesn't open at all. I checked the wiring multiple times but couldn't see an issue. I also checked the voltage coming into the throttle body which read about 5V. I checked online and that's what it should read. I checked if the pedal could be causing the issue, which I found that it is not. I also checked all the fuses and relays related to the throttle body. Any help on this would be appreciated!! I've been stuck on this issue for a couple days.

 

So you swapped the engine wiring harness. Which one did you swap out? The one that came with the engine or the one that was in your car already?
The JDM engine should be plug and play with your existing wiring harness...assuming you picked up a non-revup VQ35DE.

It sounds like you may have crossed some connections or possibly damaged the wiring harness during the swap. I suggest pulling up the wiring diagrams from the FSM and checking continuity between your main PCM plug and throttle body. Obviously do this with the battery disconnected.
Cheers
-Icer

 

I swapped the old motor harness onto the new one. I called the place I got it from and they said it is a non-revup engine. The harness going into the ECU is what looked different, that's the reason I swapped it. Is there a way to check if it's a revup or non-revup?

Edit: I just read up on it and JDM and US did have some differences in the harness connectors. I'll be checking wiring again later today and update this thread.

 

Yes, the JDM harness won't work, not because the connectors or pinouts are "different" but because the routing would be a mirror image of the NA market (LHD) models. The JDM harness is meant for a right-hand drive vehicle, so the PCM would be on the left and all routing of wiring starting from that side. I would still highly recommend keeping that JDM harness for spare plugs. These cars are getting old and plastic locking tabs and such are prone to breaking/cracking. Having some spare pigtails is always a good thing!
Good Luck!
-Icer