Error code 205 appears on the Elegoo Centauri Carbon 2 Combo when the printer cannot detect a valid reading from the NTC100K chamber thermistor. The error typically triggers at startup or during preheat, halting the print before it begins.

What the Error Means

The chamber thermistor monitors the temperature inside the build volume. Error 205 indicates the sensor reading is absent — the motherboard sees no signal at all from the thermistor port rather than an out-of-range reading (that is error 206). The most common causes are a loose or disconnected thermistor cable, a physically damaged NTC100K thermistor element, or a failed thermistor port on the motherboard itself. At room temperature (25 °C) a healthy NTC100K thermistor reads approximately 100 kΩ ± 1% on a multimeter.

Step-by-Step Fix

1. Power off the printer and unplug it from the wall. Allow all heated components to cool completely before opening the enclosure.
2. Remove the lid and bottom cover. Both are secured with ten M2 screws — use a 2.0 mm Allen key. Set the screws aside safely.
3. Locate the chamber thermistor cable and trace it to its connector on the motherboard. Firmly re-seat the cable at both ends: the thermistor body and the motherboard port.
4. Set your multimeter to the 200 kΩ range. Unplug the thermistor cable from the motherboard and probe the thermistor leads directly. A reading close to 100 kΩ at 25 °C confirms the thermistor is healthy.
5. If the resistance reading is open-circuit (OL) or near zero, the thermistor element has failed. Replace it with an NTC100K chamber thermistor rated for your printer.
6. If the thermistor tests within spec but error 205 still appears after reassembly, the motherboard thermistor port is faulty. Contact ELEGOO support for a motherboard replacement or further diagnostics.
7. Reinstall the covers, restore power, and run a preheat cycle to confirm the error is cleared.

Parts Required

• NTC100K chamber thermistor (replacement, if resistance test fails)
• 2.0 mm Allen key
• Digital multimeter (200 kΩ range)

If error 205 persists after replacing the thermistor, contact ELEGOO customer support with your order details and the diagnostic results from the resistance test.

Frequently asked questions

What does Elegoo 205 mean?

Error code 205 appears on the Elegoo Centauri Carbon 2 Combo when the printer cannot detect a valid reading from the NTC100K chamber thermistor. The error typically triggers at startup or during preheat, halting the print before it begins.

How do I fix Elegoo 205?

Error 205 on the Elegoo Centauri Carbon 2 Combo signals a missing or failed chamber thermistor. Learn how to diagnose and fix it in minutes.