I bought a Frontier yesterday morning in Houston,TX. Clean truck, everything worked, drove great. Made it 160-170 miles north of Houston and it went into limp mode and told me the check the 4x4 system. While waiting for a tow truck, about an hour, I started it back up after eating to sit in the AC and wait. Everything seemed to be ok, no check lights and it drove ok. Made it into Arkansas, about 40 miles west of Little Rock and it went back into limp mode only this time much worse.

Code it sent on the first limp mode were U1001 and U1004. Read online and people were saying to check ground bars for ECM and other computers. They kept saying there is a ground bar near the steering colum but I don't see any grounds. Other problem it could be is one of the computers is fried. I check grounds and the wire harnesses I could find under the hood and up under the dash on the driver side. Everything is tight.

Now it's saying U0101, and P0335. Trucks instrument panel doesn't show any errors after i had the codes checked last night in BFE Arkansas and let it set for 30 minutes while the store clerks at an autozone tried finding an answer and checking the battery, which tested good. Truck also won't shift out of 1st gear now. Displays D on the dash, manual shifting doesn't do anything. No check engine light is on now.

Is there a way to run a test on the transmission without taking it to a dealer as it's Sunday. I had to grab a hotel for the night after the second limp mode. Still about 300 miles from home and trying to figure out what to do about this whole situation.

I don't have a frontier or any nissann for that matter but I bet your tranny isn't toast. It sounds like it is a computer problem. I wouldn't think your tranny would throw you in limp mode with one code then "fix" itself with a bit of a brake only to go into limp mode again throwing a bunch of different codes. I could be wrong but this is what I think.

Your welcome for the zero help I have been.

Age, mileage?

Wiggle the connect to the computers. Check the battery connection, etc.

Then probably a sensor.  If the car parts shops dont keep the computer in stock, it isnt a common problem.

ETA:
Reread thread title. Nevermind age question.

Sounds more like an electronics issue if it drove fine after the first incident. By 2011 the tranny issues in the nissans were fixed. I think you're gonna have to get it to a dealer to run a check on the ecu. Or if it was me, I'd call the asshole I bought it from and get my money back.

U codes are communication error codes. This is likely a bad ground, frayed wiring, corrosion, or just a plain bad sensor. P0335 is a crank position sensor code - this would definitely put the truck in limp mode, but I personally would treat it as a red herring considering the U codes.

ETA: I may be giving you information you already have, but U1001 is a short to the ECM, u1004 is a check engine light, u0101 is no communication to transmission control module. I'd pony up for a good wiring diagram.

Mileage had just rolled over the 97k when it happened the first time. I'll hopefully have good news tomorrow when the dealership opens. For now I'm back home and sleeping in my own bed. My old trusty 97 pathfinder sitting outside may not be so bad after all.