I’ve researched extensively for the last week. Going down the highway engine raced for a minute then went into limp mode. Something was ran over on the road prior to, but not close enough to think that caused it.

2006 G35 automatic sedan, de motor w/ 265k miles
Burns through oil like crazy (probably going to need to do the notorious gasket fix soon)
Tpms light is always on
Small-ish exhaust leak, pretty sure around the cat bc one o2 sensor is reading half of the values of the other 3
Check engine has been on and WAS throwing p0011, p0420 and p2a03 prior to putting in both new camshaft position sensors, a new crankshaft position sensor, and a new maf sensor in the last few days
Reset ecm several times by pedal and by disconnecting the battery
Erased all codes
Still in limp mode
Ran full system scan and am getting these non-engine codes:
C1130
B1054 & B1049
C1705, C1706, C1704 & C1707
U1000
B2013
Haven’t driven it long enough for check engine light to come on again, have only gone around the block to see if it was fixed

So, I’m thinking I need to check the wiring harness to see if that was damaged on the highway. Also the rear brake pads are pretty low (~3mm) and the tire pressure was down to about 20psi all the way around. Idk if either of those could put it into limp mode. Tires were filled to 38psi, but brake pads have not been replaced. AT fluid looks fine, I constantly top off the oil and coolant level looks ok. Also of note, valve covers were replaced about 2 months ago but I’m still seeing pooling around the top of the spark plugs… could possibly just be from spills when topping off though. Also when I was underneath changing cam sensor, I saw some fresh oil on a cross member near the passenger side tire.

Please let me know your thoughts. I know it’s a process of elimination but I really don’t want to keep replacing things that aren’t the issue lol.

 

After driving it around more to try and get any codes to pop back up, I’ve noticed a couple things. One, the brake pedal makes some weird noises, almost like a pressure let off sound but a weird, deep tone accompanied by some clicking sounds. Two, there is a fast rattle when accelerating that sounds kind of like a rattle can but not quite so high pitched. Neither coasting or idling produce this rattle. Also the pedal noises sometimes happen while idling in park, occasionally accompanied by the vdc, slip and ses lights which disappear again quickly.

I’m picking up some JB Weld extreme heat to fix the exhaust leak, if I can find it.
Changed out the PCV Valve this morning to hopefully alleviate some of the oil consumption, although the old one still rattled pretty well.

PLEASE HELP!

 

Made a video with the live O2 readings but I have no clue what I’m looking at. I uploaded to YouTube in hopes of some quick replies. Here is the link:

 

Ran it long enough to throw codes again. Now it’s showing these three engine codes:
P0102, P0300 & P0133
So the maf sensor code could be because I ordered a Hitachi sensor from Amazon, but I opted for the used one at half price to give it a try. I know, kinda dumb but a lot of those are still new, just someone ordered the wrong thing and sent it back. So I may order another one, new this time.
The other 2 codes I’ll do some more research but for now I’ll pull the plugs and see if anything is off in there. Just changed them about 5k miles ago so they should be good. Although I’m not sure if they were gapped properly. I will double check that.

 

Lets start with the U1000, basically that means there's a network communications issue (CANBUS) and that one of the several computers isn't talking. Either from damaged CANBUS wires or more likely because the computer died.

B1054 - Driver side airbag circuit open stage 2 wiring

B1049 - Driver side airbag circuit open stage 1 wiring

Pull and inspect the airbag, if it looks good it's probably the spiral cable/clockspring.

C1130 - VDC/ABS computer not receiving proper signal from the ECM

C1705, 1706, 1704, 1707 - All four wheel TPMS sensors

B2013 - Guessing this was a typo, I don't think the G35 throws any B codes. However it does come back as a steering lock code when I googled it, couldn't find it in the FSM though.

The U1000 code is probably what's causing the issues, some computer isn't working properly, my gut feeling is the TCM.

 

Oops, started writing that post this morning before a 3 gun event, picked up the reply hours later when I got home and it looks like you added more detail.

Does your scanner not show anything for bank2 sensor1 and bank2 sensor2? Does your scanner support ISO protocol 9141-2 ?

P0102 - MAF sensor, does the car run with the MAF unplugged? Is it still in limp mode?

P0133 - O2 sensor bank1 sensor1, this is your air/fuel sensor. Check the harness to make sure it's not damaged but it probably needs to be replaced if the computer is throwing that code.

Have you pulled and inspected the plugs lately?

 

Is there a cheat code for replacing the TCM if that ends up being the issue? Looks like close to $400 new. And is it really VIN specific?

I was leaning more towards getting a new maf sensor first seeing as how it threw that code again after replacing with the “new used” one. The Amazon one did have some scratches on it so for all I know someone took their old one out and sent it back as a return and kept the new one.
I checked out as much wiring as I could, along with checking all the fuses and everything looked fine there.
As far as my scanner goes, it’s the Innova dongle so it isn’t the most in-depth scanner out there by any means.
Car does still run with the maf sensor unplugged and it is still in limp mode when doing so.
Just replaced plugs about 5-10k miles ago and no, I didn’t get around to pulling those today but it’s on the to-do list for tomorrow.

 

 

Focus on the MAF and that A/F O2 sensor. Those things will directly affect powertrain control as well as limp mode. After reading the replied I found I'm sort of leaning towards the U1000 being something to do with the ABS/TCS/VDC since you're also throwing all 4 TPMS sensor codes.

As for the TCM, buy a used one, it won't require any programming if it's a used one. Brand new will need to be programmed at the dealership.

Thoroughly inspect those harnesses for the MAF and O2 sensor though, if they're damaged, melted, broken pin, etc then it could just be a bad harnesses. Not super common on Nissan since they actually use very robust harnesses (except for the cam sensor ones which like to break at the latch), but you need to inspect those things as well. O2 harnesses like to melt, just follow the exposed wire and check it all out. If it's not something obvious it's probably just the sensor.

 

Should there be a plug in this hole? Looks like maybe AT drain plug, but fluid level looks fine, if not a little high.