It shows "CPU FAN Error" on startup even though the fans are spinning

Possible solutions

Choose the method that matches your situation. Start with the simplest suitable option and check the result. If the problem is fixed, you do not need to continue with the other methods.

1. CPU_FAN connector check

   Fits a regular CPU fan.

   Steps to follow

   1. Turn off the computer and unplug the power cord. Find the CPU_FAN socket in the manual.
   2. Check that the cable that transmits the speed signal of the CPU cooler is connected exactly there, and not just to the hub of the case fans.
   3. If a distributor is used, check in the manual which branch of it transmits the revolutions. Do not confuse the fan and RGB connectors.
   4. Turn on BIOS monitoring and check rpm and temperature. If the temperature rises unusually quickly, turn it off.

2. Slow fan or AIO configuration

   Change the warning limit only after confirming normal cooling.

   Steps to follow

   1. Refer to your cooler's manual to find where the pump and radiator fan signals should connect.
   2. In the BIOS window, compare the displayed speed with the cooler's normal operation. Zero is not the same as slow but steady revs.
   3. If the fan is spinning normally, but below the warning limit, adjust the low speed limit according to the motherboard manual.
   4. Save and check the next run. If the signal goes dead or the fan stops, correct the cause instead of disabling monitoring.