Prusa error 13206 (Hotend Maxtemp Error) appears on the MK4 and is reported as #26206 on the MK4S, #21206 on the MK3.9, #27206 on the MK3.9S, #23206 on the MK3.5, #28206 on the MK3.5S, and #31206 on the CORE One. The firmware recorded a nozzle temperature reading above 305°C, a value that exceeds the safe operating ceiling for the hotend assembly.

What the Error Means

An over-temperature reading of this magnitude is almost always caused by a thermistor malfunction rather than the heater actually producing that much heat — a genuine 305°C hotend would begin to damage the PTFE and polymer components before triggering this error. When the thermistor produces a corrupted signal (typically due to a damaged wire or a loose connection), the firmware reads a runaway-high temperature, shuts down, and raises the Maxtemp error to protect the printer. Less commonly, a short in the LoveBoard circuit can also produce spurious high readings.

Step-by-Step Fix

1. Power off and cool completely. Let the hotend drop below 40°C before handling any cables or components.
2. Inspect LoveBoard heater and thermistor cables. Access the LoveBoard per your model: on the CORE One, remove the side panel with a T10 Torx driver; on MK4/S and MK3.9/S, slide the extruder cover upward. Examine each connector — the heater cable and the thermistor cable — for full seating, bent pins, and any insulation that appears melted or cracked.
3. Check the main LoveBoard cable at the xBuddy board. Follow the cable from the extruder to the xBuddy board and verify it is not pinched where it bends around a bracket or exits the cable chain. A pinched cable can create an intermittent short that reads as a temperature spike.
4. Inspect the extruder protection fuse (MK4/S, MK3.9/S). Open the xBuddy enclosure and check the extruder fuse for continuity. While a blown fuse normally causes undertemperature errors, confirming its state rules out board-level anomalies.
5. Measure resistance with a multimeter. Test the thermistor resistance at room temperature — it should read approximately 100 kΩ for an NTC 100k thermistor. A reading near 0 Ω or open circuit confirms a failed thermistor. Measure heater resistance (typically 14–16 Ω) to rule out a heater short.
6. Replace the LoveBoard if wiring checks pass. If all cables and components measure within spec but the error recurs, the LoveBoard itself may have an internal fault and will need replacement.

Parts Required

• Replacement NTC 100k thermistor (if resistance is shorted or open)
• Replacement LoveBoard (if all downstream components test good)
• Replacement extruder fuse (MK4/S, MK3.9/S — verify rating)
• Digital multimeter
• T10 Torx screwdriver (CORE One)

If the LoveBoard replacement does not resolve the error, contact Prusa Support for further diagnosis — a fault at the xBuddy board is rare but possible.

Frequently asked questions

What does Prusa 13206 mean?

Prusa error 13206 (Hotend Maxtemp Error) appears on the MK4 and is reported as #26206 on the MK4S, #21206 on the MK3.9, #27206 on the MK3.9S, #23206 on the MK3.5, #28206 on the MK3.5S, and #31206 on the CORE One. The firmware recorded a nozzle temperature reading above 305°C, a value that exceeds the safe operating ceiling for the hotend assembly.

How do I fix Prusa 13206?

Prusa error 13206 means the nozzle temperature exceeded 305°C. This thermistor fault guide covers LoveBoard cables, fuses, and multimeter testing.