Error 104 on the Elegoo Centauri Carbon and Centauri Carbon 2 Combo means the printer firmware cannot read a valid temperature from the hotend NTC thermistor. With no trustworthy nozzle temperature signal the heater cannot be controlled safely, so the printer halts immediately.

What the Error Means

The hotend NTC thermistor sits inside or alongside the hotend assembly and feeds real-time nozzle temperature data to the toolhead board and then to the main motherboard. Error 104 fires when that reading is absent, impossible (far outside the valid temperature range), or wildly unstable — typically from a disconnected connector at the toolhead, a broken or pinched thermistor wire, or a thermistor that has failed electrically (open or short circuit). Unlike error 103 (which concerns the heater element), error 104 is purely a sensor fault. A damaged toolhead board thermistor input circuit can also generate this error even if the thermistor itself is good.

Step-by-Step Fix

1. Power off and unplug the printer before touching the toolhead or any wiring.
2. Locate the hotend thermistor connector at the toolhead board. It is a small two-pin connector separate from the heater cable. Unplug it, check the pins for corrosion or bent contacts, and reseat it firmly.
3. Trace the thermistor cable from the toolhead board down through the cable chain to the motherboard connector. Look for visible cuts, pinching against the frame, or heat damage near the heater block.
4. Measure thermistor resistance with a multimeter. Probe the thermistor terminals at room temperature and compare to the expected NTC value in the Elegoo Centauri Carbon wiki. A reading of zero or infinity (OL) means the thermistor has failed.
5. Replace the thermistor if it is out of spec. Use only an Elegoo-specified replacement to ensure the correct resistance-temperature curve for the printer’s firmware.
6. If the thermistor tests in spec, inspect the toolhead board connector and the relevant pins on the motherboard. If the toolhead board appears damaged, contact Elegoo support.
7. Power on and verify that the nozzle temperature displays a realistic ambient reading (18–30 °C) before heating.

Parts Required

• Replacement hotend NTC thermistor (Centauri Carbon / Centauri Carbon 2 Combo spec)
• Multimeter (for resistance measurement)
• Replacement toolhead board (only if board is confirmed damaged — via Elegoo support)

If error 104 returns after a thermistor replacement, escalate to Elegoo support for assessment of the toolhead board or motherboard thermistor input circuit.

Frequently asked questions

What does Elegoo 104 mean?

Error 104 on the Elegoo Centauri Carbon and Centauri Carbon 2 Combo means the printer firmware cannot read a valid temperature from the hotend NTC thermistor. With no trustworthy nozzle temperature signal the heater cannot be controlled safely, so the printer halts immediately.

How do I fix Elegoo 104?

Elegoo error 104 means the hotend NTC thermistor is returning an invalid reading on the Centauri Carbon. Learn to trace the cable, test resistance, and replace the thermistor.