After starting the car and just driving in normal conditions, not using 4wd (hardly ever even) I got the “service 4wd” message.
Has 80k miles
does anyone have an idea what this could be? Is this fairly common? I’ve seen a lot of forums with people having this error message while using 4wd, but this was just driving to the grocery store on a normal dry day. Thanks

 

Are you getting any drivetrain codes? I am not a fan of the automatic four-wheel drive transfer-case systems on any vehicle, so I am no expert on them, but I have seen this issue show up before here.

I am jaded as I used to own a Jeep CJ-5 with solid-axle (Dana-30) manual Warn locking hubs and floor shift 4WD and a 4-speed stick. no automatics at all. Back then there was no A/C; the heater wasn't very strong and if you wanted a AM/FM/C/D player, it didn't come from the factory. AM radio only and the tachometer was a $150 dollar option. Did have power steering and power front disk brakes however. The 258 cubic inch I-6 mill was solid as a rock too.

That said, I cheated and visited a 4X4 GM forum and it seems that the fix *might* be easy and cheap as it only involves replacing the drivers 4WD dash control switch, which runs around $30 USD, including shipping. This is what I found:

Transfer Case Driver Control Switch GM# 25878425@/oem-parts/gm-switch-25878425] https://www.newgmparts.com/oem-parts/gm-switch-25878425

I hope that that will help you out and that it works, but I cannot assure you of that, only going by the words of others in your predicament, not my experience. Also it seem that no codes will show up with this issue either, which seems to involve the circuit board not being properly designed, cracking, or poorly manufactured, likely in Asia.

 

It more than likley is the switch, do you have the indicator led on (on the switch)

 

When's the last time you had your transfer case fluid checked or changed?