That means your extruder reached the max safety limit and was shut down. Now unless you smelled plastic burning this was not the actual case. What normally happens here is one of two things all having to do with your thermistor.
Either the insulation on one of the wires has slipped back and it is now touching the brass body of the heater block, or both wires insulation has slipped back and they are both now touching.
To understand the logic you need to know how a thermistor works. It is a resistor who's resistance changes based on temperature. The hotter it get the lower the resistance. Likewise the cooler the higher it goes. The mainboard interprets this higher resistance as a temperature value. Now if the thermistor wires short to each other or to the heater block then this is seen as a complete short or nearly no resistance. The machine sees this as a temperature that is off the scale and exceeds the preset safety limit which I believe is 250 on stock firmware.
If you have a DMM you could unplug the wires at the top of the extruder and measure across them to see if there is any resistance. At room temp the resistance should be around 100K ohms. If it checks OK there, then measure between each wire and the brass heat block. There you should get a very high if not infinite resistance.
Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.
