Okay, so, this is my first 4WD vehicle. I just got it 6 weeks ago. It is an 06 Pathfinder LE. I usually set it to AUTO, and that's generally how it's driven being I live in the mountains and it never flipping stops raining.

Sunday 4/19, steep incline downhill hunting the Pokemon, I see the warning light is on and the dash symbol indicating what mode I am driving in is blank. I have no idea what that is, but assume it's not bad because I'm living on a prayer.
Monday 4/20, having to wait in the car with all 4 kids at the urgent care because my daughter is sick. COVID has us sitting in the vehicle I have the car off, set to accessory mode so it's playing the radio still. Battery ends up dying, my own fault. Good thing, though, because apparently my battery was bad and a bit small. Get it jumped.
Tuesday 4/21-Thursday 4/23, continue driving in AUTO. Off and on the 4WD warning light comes on. Either when on completely flat, dry asphalt or when trucking uphill, does not seem to matter.
Thursday I set to 2WD thinking hey, that might fix it.

Friday I replace the battery. Much better fit, and immediately notice a difference in how it drives. BUT

the 4WD warning light keeps coming on. I followed some diagnostic advice from the forum (this one or another one, I don't know) as well as my mechanic (who didn't even come out, just told me to try a bunch of stuff). This ranges from switching while in Idle between 2WD and 4H, and it includes switching between gears, in different settings. I finally took it to not one, not two, but three auto shops, one who finally diagnosed it with the P1828 code.

I'm taking it to yet another place tomorrow because the place that was able to diagnose it was not able to service it, but I have absolutely no idea what is going on as it doesn't seem to be driving at all differently and I can find very limited information specific to that code and Nissan. Am Trying so hard not to stroke out over Bernadette. I read somewhere to tighten and clean connectors and relay contacts but I have 1) no idea where these are located and 2) no idea if I even have the tools to do that. Any advice is appreciated, as my husband is typically not very handy so I have to do it by myself lol

This doesn't get talked to much about because it only happens on the Pathfinders with the AUTO mode transfer case. I ran into the same problem on my 2006 LE and there is a very good chance that you have the same problem. The code is for a line pressure issue in the transfer case. 99% of the time this code occurs, especially if it's intermittent, is because of a poor connection at the transfer relay OR a bad relay. The relay is Nissan P/N 25237-EA000 and is the same relay that is used for the air suspension in the last generation of Nissan Armadas. Here's a link to one:

https://www.amazon.com/2004-2012-Nissan ... B00SI25NGS

Your transfer case has two pumps; one is a manual pump, much like a manual transfer case, and the other is an electric pump that bolts to the back of your transfer case. When you are in AUTO mode and at idle, in reverse or driving at speeds below 35 MPH, the electric pump is powered-up by the transfer relay so it can provide lubrication to the wet clutch. After 35 MPH, the manual pump can sufficiently supply the wet clutch will oil. If the transfer relay doesn't work properly, the pressure switches will sense the low or no oil pressure to the wet clutch and trigger the code(s). The transfer relay is bolted with a single, 10MM head bolt to the driver's side of the engine compartment, not far from the brake booster (it's not hard to find). It actually has two harness connectors going to it.
In my case, I removed the relay and cleaned up the blade terminals on it. Then, I used a pin to tighten up the female connectors in the harness connector. I put it back together and it was good for about a year, when the problem re-occurred. So, I checked the relay and one of the blade terminals on the relay had corroded, so I replaced the relay with a new one and that was the last problem I've had with it and that was several years ago. No, there's no way of saying with 100% confidence that this is your problem, but the few times I've heard of other people having this problem, it was fixed by replacing the transfer relay. It runs in the $30 range, so it's a cheap relay, but if it were mine, I would replace the relay with a new one before pulling out my hair and then see if the problem raises its ugly head, again! Here's my original thread on the topic:

viewtopic.php?p=98193#98193