21202
Easy Fix
Prusa · FDM 3D Printers
Print Fan RPM Anomaly - Part Cooling Fan Speed Inconsistent
Quick Answer
Error code 21202 on your Prusa FDM 3D Printers means: Print Fan RPM Anomaly - Part Cooling Fan Speed Inconsistent. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Run a fan test from LCD > Settings > Fan Test and observe the fan behavior at various speeds
2
Inspect the fan visually for physical damage to the blades or housing
3
Check the fan cable routing for pinch points that could cause intermittent connection
4
Update the firmware to the latest stable version to rule out software-based RPM reporting issues
5
Replace the fan if it shows visible wear, makes grinding noises, or cannot maintain a stable RPM
Pro Tip
This is a common issue that most users can resolve without specialized tools. Try the first step before moving on to more complex solutions.
Parts You May Need
Replacement part cooling fan (model-specific blower or axial fan)
Fan duct/shroud (if the original is warped from heat)
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