When I bought my early 2001.0 the previous owner gave me two keyless remotes with the understanding one didn’t work anymore.
Of course I later learned about the model #ers and cost associated with “/A” units.
I opened the inoperative one up and was surprised to see surface mount ‘mechanical’ buttons. With nothing to loose I sprayed MAF Cleaner, with straw attached, directly into all buttons while clicking buttons repeatedly (gloves/goggles). This resulted in partial function, so I disassembled again and repeated process (long duration sprays while clicking buttons).

I’ve been waiting a while to post but can now report that this remote continues to work just fine.
Obviously there could be many reasons as to why these remotes fail but in this particular case cleaning solved the issue.
I have no idea whether or not MAF Cleaner is safe for this use. The MAF Cleaner seized up some window switches when I tried it recently, until I sprayed some silicone on those switches. So use at your own risk (I did not follow up with silicone spray on remote buttons).

‘If’ these mechanical buttons are the main cause of failure it seems it isn’t too hard to replace them yourself. I’m sure this is all the resellers are doing.
The soldering gun used in the video is about $50 and the momentary PCB switches are about $7 for four or so. But you gain tools & parts without having to reprogram for your trouble. (not a Pathfinder remote in video)

https://youtu.be/pQr0E0znBfA?t=103

MAF cleaner is residue-free and great for electrical contacts, but it also affects many kinds of plastic used in interior parts like window switches. So it should only be used on bare circuit boards and electrical parts, never surrounding plastic interior parts. Engine room parts are a whole different breed of plastics and are generally safe for any type of spray cleaner.

Great point. In my defense though I did have enough sense to test the MAF Cleaner (CRC) on the face of my removed/replaced old wood grain/clock/air vent module, letting it sit on top a while to evaporate and there was no change to finishes. But I imagine those little switch housings on the window circuit board are just some cheap white acetate etc. (Dumb luck but the switch continues to work better, less resistance and feels like passenger switch now - go figure).

Speaking of the window circuit board module (and pressing luck)... I think I read somewhere here where you explained to the poster that those modules are year specific(?) if they were to go looking for a backup or replacement ?

Yah, get the part number off the existing one or find it by VIN in NissanPartsDeal. There are a lot of lookalikes, some of which will smoke (literally) if you plug them into the wrong application.

wow, I had no idea those OE modules were still available. Good to know, thanks. Just saw the look-alike too and for $40 would have assumed it was worth a try for a backup and bit.

Next junk yard trip I'll pull an '01 module and see if passenger switch slider is same as drivers and attempt a desolder.

https://imgur.com/a/9Z7xTOr
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Follow up:
In a conversation with an online reseller of used Pathfinder '/A' remotes etc. (specifically enquiring about their stock of '/A' remotes) I asked if these remotes had any work done on the circuit boards - i.e. parts replaced. Their answer was "No, we only 'clean' the circuit boards and test remotes to make sure they work".

follow up: Defeating Panic Button

One of the most annoying things about these keyless entry fobs, besides needing to push twice to open all doors, is the Panic Button. I accidentally set off the horn whenever random external pressure is applied to fob like leaning against something etc. while it's in my pocket. Once is enough, but after the 6th time I decided the cost of possibly ruining a remote was worth it.
So this is just to let anyone know that desoldering the mechanical button from the circuit board leaves keyless fob fully operational. I did try slicing off the little nib on the back side of red rubber button first hoping it would make it less sensitive but that wasn’t enough.
If you don’t wish to desolder you could also cut a trace or two leading up to that button.

https://imgur.com/uxJis34