I have this Ender 3 V2 Neo that’s been doing a really good job until now. I don’t print a lot, but I got it used so it’s probably got some hours on it. It just started doing this: It stops mid-print and gives an alarm that says bed and nozzle temperature is either too high sometimes or too low sometimes. It won’t do anything from there and I have to turn it off, and luckily it gives the option to resume when I turn it back on. It’s getting more frequent, to the point I’ll have to finish this print on my other machine. I know a little bit about hotends and components, from fiddling with my Prusa, but I haven’t had to touch anything on this one yet, so I don’t know its particular ins and outs.
Side note: when it happened just now and I resumed it, the Z was off quite a bit. High enough to have no adhesion to the existing material. The last 3 or 4 times, it resumed at exactly the right Z and continued printing well.
I think I’d start by checking the connections on the hot end thermocouple. If ok, replace the thermocouple. It’s an inexpensive part. Many people overtighten the thermocouple retaining screw and damage the wires.
I snugged that screw down a little and it cleared up. Thanks.