The Anycubic “Heating Failed: E1 — PRINTER HALTED Please Reset” message appears on Marlin-based Anycubic printers including the Kobra 2 Neo, Kobra 2, Kobra Neo, Kobra Go, Kobra Plus, and Kobra Max. When this error occurs the printer immediately halts all movement and heating, requiring a manual reset before it can be used again. It indicates the E1 (first extruder / hotend) failed to reach its target temperature within Marlin’s thermal runaway timeout window.

What the Error Means

Marlin firmware monitors heating progress during warmup: if the hotend does not gain a minimum number of degrees within a set time period, the firmware triggers a thermal runaway protection halt. This is a safety mechanism — a heater that is not heating could mean a disconnected thermistor is reporting a false low temperature while the heater continues to run, which is a fire risk. The most common hardware causes are a broken or partially disconnected heater cartridge, a loose thermistor cable giving incorrect temperature feedback, a failed power supply unable to deliver the required current, or physical damage to the hotend wiring.

Step-by-Step Fix

1. Power off the printer at the main switch and unplug it from the wall. Allow the hotend to cool fully — at least 10 minutes — before touching any wiring.
2. Locate the heater cartridge cable and thermistor cable at the hotend (typically routed through the cable drag chain). Unplug both connectors and reseat them firmly at the hotend end and at the mainboard end, pressing until you feel or hear the latch click.
3. With the printer still powered off, use a multimeter set to resistance mode. Disconnect the heater cartridge cable at the mainboard and measure across the two heater cartridge pins: the reading should be 9–12 Ohm for a 24 V cartridge. A reading of 0 Ohm (short) or open circuit confirms the cartridge has burned out and needs replacement.
4. With power restored and the printer commanded to heat, measure DC voltage at the mainboard’s hotend heater output connector during the heating phase — it should be approximately 24 V. If the voltage is absent, suspect the mainboard heater port or the power supply.
5. Inspect the heater block area for a silicone sock. If it is missing or torn, install a new one — without thermal insulation, drafts from the part-cooling fan can strip heat from the block faster than the cartridge can supply it, causing a false Heating Failed trigger.
6. After any repair or reconnection, power on the printer and attempt to preheat the nozzle. If it reaches temperature and the error does not return, run a short test print to confirm stability before committing to a long job.

Parts Required

• Replacement heater cartridge (24 V, compatible with your Kobra model)
• Replacement hotend thermistor (if thermistor continuity check fails)
• Silicone heater block sock
• Multimeter

If the error returns after replacing both the heater cartridge and thermistor, contact Anycubic support — the mainboard or power supply may require evaluation.

Frequently asked questions

What does Anycubic heating-failed-e1 mean?

The Anycubic "Heating Failed: E1 — PRINTER HALTED Please Reset" message appears on Marlin-based Anycubic printers including the Kobra 2 Neo, Kobra 2, Kobra Neo, Kobra Go, Kobra Plus, and Kobra Max. When this error occurs the printer immediately halts all movement and heating, requiring a manual reset before it can be used again. It indicates the E1 (first extruder / hotend) failed to reach its target temperature within Marlin's thermal runaway timeout window.

How do I fix Anycubic heating-failed-e1?

Anycubic 'Heating Failed: E1 PRINTER HALTED' means Marlin firmware stopped heating the hotend. Fix heater cartridge and thermistor faults on Kobra 2 Neo, Kobra 2, and Kobra Neo.