ASUS and American Megatrends motherboard users can come across the error while their Windows PC or laptop startup.
Usually, when a CPU fan error appears, the PC shuts itself down. This message shows that it may be a CPU overheating. However, there are some cases where CPU fan error appears even though the fan is running.
Here we will explain what is this error, why it appears and how you can easily fix it once and for all.
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Why CPU Fan Error Appears
Usually, the ASUS fan error appears on bootup or during the startup process. The error message sometimes varies but you will see a screen similar to this:
What Causes ASUS CPU Fan Errors on Startup?
This error shows that the motherboard safeguard feature is working fine. If the fans don’t spin properly then it may cause an increase in CPU temperature, resultantly it can damage internal hardware.
The most common reason that triggers this error is.
- CPU fan isn’t connected with the motherboard cpu_fan header properly.
- Incorrect fan settings in BIOS.
- Dust and debris slowed down the fan RPM.
- The fan is broken permanently.
Now Let’s Fix CPU Fan Error on Boot/Startup
This error may be related to hardware or software, so the fixes may differ for each user.
Users who are using Corsair or NZXT Kraken AIO CPU cooler mistakenly connect the wrong pump header in the motherboard. Hence, see this error message.
Fix 1. Make Sure CPU fan is Connected Properly
This fan error is appearing on Asus & megatrends motherboard because either nothing is connected with the cpu_fan header or it’s plugged in the wrong header.
- Please make sure the CPU FAN is installed on the right position of the motherboard and twist the screws tightly
- For those who are using a water cooler i.e. H100i or H100i V2 and still fan speed error pops up, connect the hydero pump to the AIO_PUMP header (not in CHA_FAN).
- Ensure that the CPU FAN cable is securely installed to the CPU_FAN connector instead of the CHA_FAN.
Fix 2. Set CPU Fan Speed Lower Limit
Does the CPU fan is running at a required RPM? Most of the time, the Asus fan error gives you a hint that the fan is underperforming concerning its RPM.
For users who are using NZXT, Corsair fan with lower revolution speed, the system may not be able to correctly detect it.
Set the “CPU Fan Speed Low Limit” to 200 RPM in BIOS configuration.
To change fan speed lower limit, follow these steps:
- Get into BIOS by pressing F1, F10 or Delete key upon startup.
- Navigate to the CPU fan settings with in Advanced Settings. (This section may vary with your motherboard’s model)
- Find the setting that controls the CPU fan RPM alerts. The default value should be 600 RPM (Revolutions Per Minute).
- Lower the default to 300 RPM to 450 RPM and Save the changes.
- Exit the BIOS and boot the system.
Fix 3. Disable CPU Fan Speed Monitoring in ASUS BIOS
If the CPU fan error is appearing, but a fan is working, then you can disable this alarm. Follow these steps:
- Boot into BIOS.
- Navigate to the aforementioned Advanced settings.
- Look for the Monitoring (Monitor) section.
- Change the CPU Fan Speed to Ignore and Confirm changes.
Fix 4. Update the BIOS
Most of the time fan errors on ASUS and Megatrends related to BIOS software malfunctioning. If you simply update the BIOS version to its latest then you are good to go.
Fix 5. Check fan Settings in Your BIOS
If you have recently changed the BIOS settings, then it may be a cause why the Asus fan error is appearing.
- Open BIOS
- Select Advanced Settings.
- Select Hardware Monitor.
- There you will see the CPU Fan option.
- Enable Active Heat Sink and Fan Duct with Fan.
- Disable Passive Heat Sink and Fan Duct without Fan.
- Save your changes and exit BIOS.
Fix 6. Replace Your CPU’s Fan
If the error is still appearing on the Asus motherboard on boot up, then it may be a hardware problem. You need to buy a CPU fan and replace it with a broken fan.
Related: Best Portable Laptop Cooling Pads For Gaming
Fix 7. Clean Your CPU’s Fan
The dust is the enemy of computer hardware. When dust builds up inside it blocks fins to rotate at ideal speed.
You should regularly clean the CPU fans. To do this turn of the PC unplug the power cable and use canned air to blow the dust off.
Fix 8. Try an Alternate CPU Fan Header
Modern motherboards have multiple fan headers if one header doesn’t work. Try plugging the fan into a different slot. This sometimes fixes the CPU fan error.