- Hotend wires should be plugged into their correct ports on the underside of the extruder. The heater core is the red covered pair of wires, and the thermistor is the black pair of wires.
- Make sure the heater and thermistor are properly plugged in on the topside of the extruder as well.
- Check that the extruder power cable is properly plugged into the mainboard as well. Refer to the Robo C2 Mainboard Wiring Diagram