Extruder error please help!

I have done a search on the forum and haven't found anything as yet so hopefully someone can point me in the right direction.

I've gone to start my printer today and it connects to Pronterface fine but it gives me an extruder minimum temp error and it stops the printer from doing anything. Can't heat up, motors wont move and it says to fix the error then run M999. Exact error message:

: Extruder switched off. MINTEMP triggered !
Error: Printer stopped due to errors. Fix the error and use M999 to restart.

Can someone help me fix the mintemp error? And I have no idea what M999 is either. Is there a guide to Pronterface somewhere?

Thanks

That typically means that your thermocouple has failed or become disconnected, and the firmware sees an unreasonably low value (default is below 5, IIRC) and refuses to heat because of it. M999 is a gcode that resets the controller after the problem is resolved, but then again, so would a hardware reset or power cycle.

- Tim

Edited 1 time(s). Last edit at 06/11/2015 03:02AM by tadawson.

I just checked the cables to extruder and at the control board and they are all just as tight as always. Not sure where to check for the thermocouple. The printer was left on but idle overnight by accident, could that have fried the thermocouple?

Pronterface reads the temp hovering between 2.5-3.5 degrees so that would be in the less than 5 degrees range you said.

Update - The extruder was way happier today. No error message when I turned it on and been running fine. It looks like my mendel i3 doesn't like being left on and idle all night and most of the next day.

I think this means my next step will be figuring out how to program a disconnect command once the print finishes.

Thanks for all help.