Abnormal Fan Speed - Fan Manually Turns On

Bambu Lab P Series Troubleshooting
1

I’ve done a good amount of searching but haven’t found anything that works yet. I had an ABS print fail at ~5% and spaghetti everywhere. Next print wouldn’t start due to the Abnormal Fan Speed Error. P1S w/AMS.

  • I took the fan housing off, removed the fan, opened the fan casing, removed some filament that was on the inside. Very few pieces, the fan still spun freely even before cleaning.
  • Reinstalled fan, no change (with ABS print, and PLA Benchy)
  • While print was preparing, removed connector and reconnected for both the hotend and the fan (as recommended on this forum), no difference.
  • I can manually run the fan by selecting Part Fan on the MFD and turning it on, it works perfectly. It will not turn on during a print. Do I really need to buy a new $20 fan, or am I missing something?

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2

Any resolution? I am having the same problem. Abnormal hotend fan speed but all three fans will run when started manually.

3

You can’t control the hotend fan. It runs by itself when the nozzle temperature is higher than 50°C.

Set nozzle temperature about 70°C, but if the fan won’t spin then you have a dead fan.

Contact support and get replacement is a way to go but it will take time, in my case half year ago, it was 2 months of downtime due to communication back and forth with support. It’s faster if you just buy a replacement from aliexpress, cost about $10 and 15 days shipping.