CPU Fan Error ASUS on Boot FIXED (2022. 3 Fixes)

A cooling fan is one of the most integral parts of the computer processing unit (CPU). Fans are used to draw cooler air into the unit from the outside and emit warm air from the inside. It keeps every component of the CPU at a cool temperature with the help of a heat sink.

However, ASUS users have reported a problem with their CPU fan when their computer boots up. As a preventive measure, the PC and all of its components will shut down instantly. It can also lead to other serious problems, such as overheating and component damage.

In this guide, you will learn: 

  • What is the CPU fan error on ASUS motherboards or American Megatrends CPU fan error;
  • The main causes of this CPU fan issue;
  • How to fix the CPU fan error on ASUS Motherboards

So, if you have recently come across this error on your CPU, read on to learn more.

Table of Contents

What is the CPU Fan Error on ASUS Motherboards or American Megatrends BIOS?

The CPU fan error appears on the BIOS (Basic Input/Output System) startup–it is where your computer’s hardware and memory are being initialized before booting the operating system. 

In the case of ASUS motherboards, the American Megatrends logo first appears on the screen, along with other initial parts of the startup process, such as memory and hard drives. The error will soon appear with the following message:

CPU Fan Error!

Error: CPU Fan has turned off!

ASUS, American Megatrends CPU Fan Error

You will be prompted to press the F1 key to boot once again, but the problem will not go away. So, what are the causes for this CPU fan issue?

Main Causes for the ASUS CPU Fan Error upon Startup

  • The CPU fan is not properly connected – A common fix to this problem is to check if the cables for the CPU fan are connected to the right slot. Specifically, you will need to check if the CPU FAN cable is securely connected to the motherboard.


  • Slow RPM – Errors can occur when your CPU fan is underperforming due to several factors; first, check if it is clean and all blades are in proper condition. Once one of the fan blades is stuck due to debris buildup, it can cause slow rotations and will lead to hardware failure.

If you didn’t change your CPU fan for a while, it can also be due to age or wear and tear.

  • Incorrect fan settings in BIOS – Like all motherboards, ASUS CPU fans can be controlled by accessing the motherboard’s fan settings. Although the computer sets the right settings by default, you can also change them to fix the CPU fan error.

How to Fix the CPU Fan Error on ASUS Motherboards

With everything else in mind, you can now begin to try the fixes listed below. Whether your issue is hardware or software-related, we got you covered.

Remember to go through each one to test out which works the best for your PC. Also, if your CPU fan was not cleaned for a while, you can first try to open your PC and clean the dust and debris that are maybe causing this error. Nonetheless, here are some fixes that you can try:

Fix #1: Ensure that the CPU Fan is Connected Properly

One cause for the CPU fan error is the improper installation of the CPU fan cable on the motherboard. If you have mistakenly connected it to the CHA_FAN (Chassis Fan) instead of the CPU_FAN, the motherboard will not detect it properly. 

To fix the CPU fan connection issue, follow these steps:

  1. Upon installing the CPU Fan, make sure that it is in the right position on the motherboard. Also, plug all screws needed on the fan and tighten them properly.
  2. When plugging in the CPU FAN cable, ensure that it is securely connected to the CPU_FAN connector instead of the CHA_FAN.
  3. After making the proper adjustments, turn on your computer and check if the error still shows up on the BIOS screen.

Most CPU fan problems on ASUS motherboards or American Megatrends BIOS are solved once you apply this fix. If you are still experiencing the same issues, however, you can try the other ones below.

Fix #2: Change the Cooling and Fan Settings

If you have installed a new CPU fan for your PC, chances are you might have improper fan settings set on your device—specifically, the fan’s RPM. ASUS motherboards will require a minimum RPM for your CPU fan, or else it will not be recognized. 

Important: Before going straight to the steps below, make sure that your ASUS BIOS is up to date. Depending on your computer, you can visit the ASUS official website for the latest BIOS versions.

To change the cooling and fan settings via the BIOS, proceed to these steps:

  1. Access your computer’s BIOS settings by pressing the F1 or F10 key upon startup.
  2. Go to the CPU fan settings > Advanced Settings.
  3. Find the CPU Fan Speed setting. Change the default value (600 RPM) within the 300–450 RPM range.
  4. Once done, click Save and check if the error still exists on the BIOS startup.

Tip: You can also try to set the CPU Fan Speed Low Limit to Ignore and see if that fixes the CPU fan error.

Fix #3: Replace your CPU Fan

As mentioned earlier, if your PC has been running for a while, chances are some of its internal hardware will have issues. Assuming that you have tried all the fixes above, you will need to replace your old CPU fan with a new one.

Not only this will help in improving your PC’s overall performance, but it will optimize the temperature of all internal hardware, especially the motherboard. Using faulty CPU fans can also further lead to overheating and hardware failure.

Final Thoughts

The CPU fan is a critical part of your PC setup. It ensures that an optimal temperature is maintained across all internal hardware while your computer is running. Several issues with the CPU fan will prevent your computer from booting properly. Therefore, these fixes should keep you informed on solving this hardware issue.