How to Fix CPU Fan Error on Boot (Step-by-Step)

Seeing a CPU fan error on boot can be alarming, especially when your PC won’t load past the BIOS screen. Common messages include CPU fan error detected, please check, or press F1 to continue, usually on ASUS motherboards. These alerts appear when your system doesn’t detect the CPU fan or its RPM is too low.

Here’s how to fix the issue safely without diving deep into BIOS tweaks or replacing hardware.

Why does my BIOS say CPU fan error?

An error that occurs at startup caused by the central processing unit (CPU) fan is frequently the result of physical damage to the fan itself, faulty settings, or external circumstances that cause the computer to overheat and force the fan to spin at speeds that are exceptionally high.

Alternatively, errors with the computer’s central processing unit (CPU) fan might be brought on by dirt or other debris that obstructs the device’s air vents.

How do I fix CPU fan speed error?

Before moving on to more complex solutions, make sure to do the following:

• Remove the fan and clean the dust. You can use pressurized air to clean it.
• If you installed an AIO liquid CPU cooler, check to see that the Pump was plugged into the AIO PUMP port and that the AIO Radiator Fans were plugged into the CPU FAN port.
• Check to see that the CPU cooler is correctly attached to the motherboard and that the fan of the CPU cooler is specifically hooked into the CPU FAN header.
• To reduce the CPU temperatures, re-apply the thermal paste.
• Disable overclocking and custom fan curves
• Move your PC to get adequate ventilation

1. Update BIOS

It’s more likely to work out CPU fan error on boot by accessing your BIOS and update the firmware of your Windows PC.

1. 1. Download the newest BIOS version from your motherboard manufacturer’s website and copy it onto an USB flash drive.

2. 2. Open the Start Menu then click the Power button. Hold the Shift key and choose the Restart option.

   

3. 3. You should see several options available. Choose Troubleshoot followed by Advanced options.

   

4. 4. Select UEFI Firmware Settings.

   

5. 5. Click the Restart button and your computer should now boot to BIOS.

6. 6. Once you enter BIOS, look for the BIOS update option and select it.

7. 7. Now you need to choose the BIOS update file from your USB flash drive and wait while your BIOS updates.

For more details about your computer’s BIOS, check out our dedicated guide on how to check the BIOS and update it.

2. Lower the default fan RPM in BIOS

1. To fix the CPU fan speed error detected boot into BIOS on your PC.
2. Navigate to CPU Fan settings. The sections might differ based on your motherboards. The important thing is to look for anything related to the CPU Fan control, usually found in the Advanced settings menu. Now, locate the setting that regulates RPM warnings. The default value should be around 600 RPM (rotations per minute).
3. Lower the default value to 300 RPM and save changes.
4. Exit BIOS and boot into the system. This is one of the best solutions for the Asus motherboard CPU fan error.

3. Disable CPU Fan speed monitoring in BIOS

1. Boot into BIOS. Navigate to the aforementioned Advanced settings.
2. Look for the Monitoring (Monitor) section.
3. Change the CPU Fan Speed to Ignore and confirm changes.
4. Boot into Windows and look for improvements.

After that, the CPU fan press F1 error should be gone. However, if the issue persists, take your PC for diagnostics and repair.

4. Try another CPU fan header

In some cases, your PC might have more than one CPU fan header. If you face the CPU fan error, it might be because the header you are using is faulty.

The best thing to do in this case is to try another header. Also, ensure the fan is connected to the correct location (i.e., the fan header).

Read more about this topic

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5. Check other fans

Sometimes, you need to verify if your CPU fan is working well. To do this, you need to try other fans compatible with your PC.

Just make sure you connect it to the header and that the area is well-ventilated.

6. Replace the CPU fan

If the fixes above fail to solve the CPU fan error, you might need to go for broke and replace the fan. This is especially true if you tested your PC with other fans, and they worked without error.

The only thing you need to take care of is the compatibility of the fan with your PC and that you get the connection right.

7. Shut Down and Check the CPU Fan Connection

Make sure the fan is connected to the correct motherboard header. Many users mistakenly plug it into a chassis fan port instead of the CPU_FAN port.

Steps:

• Power off your computer and unplug it.
• Open the side panel of your case.
• Locate the CPU fan cable and ensure it’s firmly plugged into the CPU_FAN header.
• Plug everything back in and restart the PC.

This is the most common cause of the CPU fan error ASUS motherboard message.

8. Clean the CPU Fan and Heatsink

Dust buildup can prevent your fan from spinning correctly or reduce its RPM enough to trigger the CPU fan speed error detected warning.

Steps:

• Power off and unplug your PC.
• Use a can of compressed air to clean the CPU fan blades and heatsink.
• Make sure no cables or wires are obstructing the fan’s path.
• Reboot and check if the error persists.

9. Reset the BIOS via CMOS

If you see CPU fan error press F1, there might be a BIOS glitch or misconfiguration. Performing a CMOS reset will restore BIOS defaults.

Steps:

• Turn off the PC and unplug all power sources.
• Remove the CMOS battery from the motherboard for about 30–60 seconds.
• Press and hold the power button for 15 seconds to discharge residual power.
• Reinsert the battery, power the system back on, and check if the error is gone.

10. Use a Fan Monitoring Tool

To make sure the CPU fan is spinning properly, install a hardware monitoring tool in Windows. This can help verify RPM levels and fan detection.

Recommended tools:

• HWiNFO – Offers detailed readings on CPU, motherboard, and fan RPMs.
• AIDA64 Extreme – Useful for diagnosing fan detection issues or low RPM behavior.

If your fan shows “0 RPM,” it’s either disconnected, faulty, or not spinning fast enough for BIOS to detect.

11. Reseat the CPU Cooler

Improper mounting can cause the cooler to sit unevenly, which may stop the fan or reduce performance. If nothing else works, this step is worth trying.

Steps:

• Shut down the PC and unplug everything.
• Remove the CPU cooler carefully.
• Clean off the old thermal paste with isopropyl alcohol.
• Apply a small amount of new thermal paste to the CPU.
• Reseat the cooler firmly and reconnect the fan to the CPU_FAN header.

What will happen if the CPU fan fails?

Central processing units that have dead fans will overheat. When a computer’s central processing unit (CPU) gets too hot, there are normally built-in safeguards that will either shut it down or slow it down to prevent it from exploding.

However, suppose the computer protections fail or don’t kick in quickly enough. In that case, the central processing unit (CPU) could reach temperatures above its maximum operating temperature and burn out.

To learn more about this issue, our CPU fan is not spinning guide is a great place to start.

Check out how to lower high CPU temperature in Windows 10 & 11 to extend its lifespan.

Alternatively, you can replace the cooler, which isn’t a complex task. Did our article help you with the Asus water-cooling CPU fan error? Let us know by leaving a comment in the section below.