CPU Fan Error

A CPU fan error is a message that usually appears when the fan cannot cool hardware at optimal temperatures. Faulty fans and overheating can permanently damage computer parts, so it is essential to fix this issue.

Common causes for a CPU fan error include improper fan installation, fan damage, incorrect settings, and excessive dust. You can clean your fan and vent, check your fan’s connection, replace the thermal paste, or configure your CPU fan RPM settings on BIOS to fix these issues.

Different problems require specific solutions, so follow these troubleshooting tips to determine why your fans are overheating and causing error messages.

What Is a CPU Fan Error?

cpu fan in red lighting

A CPU fan error is a warning from your BIOS that one or more fans are spinning incorrectly. Fan issues are often triggered after your computer has shut down unexpectedly due to overheating.

Fan errors typically appear when booting up Windows, with any of the following error messages:

  • CPU Fan Error (Generic CPU fan error on boot)
  • Error: CPU Fan Has Failed (CPU fan error ASUS)
  • CPU fan speed error detected (American Megatrends CPU fan error)
  • System Fan (90B) (HP/Compaq CPU fan error)

What Causes CPU Fan Errors?

black cpu fan in computer case

If you have a CPU fan speed error or your fan has stopped spinning completely, your computer may overheat if used intensively. So, before fixing this problem, you need to find out why your CPU fan is causing an error.

Hardware conflicts with your CPU fan may cause errors, such as physical damage to the fan, improper fan installation, or dust obstructing vents – forcing the fan to run at higher speeds. The issue may also lie in the software or operating system, such as incorrect BIOS settings.

How to Fix CPU Fan Errors

compressed air cleaning computer case

Clean Your Computer

After using your computer for a while, dust can clog the fans and vents, which prevents fans from spinning as they should. To properly clean your computer of dust, follow these simple steps:

  1. Turn your computer off and unplug it from the power source. Discharge any remaining power by pressing and holding the power button for about ten seconds.
  1. Open your computer case and ground yourself to prevent electrostatic discharge from damaging your hardware. You should use an anti-static wrist strap, but you can also touch a grounded metal object while working on your computer.
  2. Locate the CPU fan and vent. Then, use a can of compressed air to blow the dust away with short puffs of air. Refrain from spraying any cleaning agents on the inside of the case because they can seriously damage your components.
  3. Put the case back in place, reconnect your computer to the power, and test your fans.

Opening some devices, such as laptops, may void the warranty or cause damage if improperly handled. If you are unsure, it is best to contact customer service to inspect your device.

Inspect Your Fan

While your computer case is open, you can physically inspect your CPU fan. Ensure that the fan is tightly secured and has not fallen out of place. If it has, you can fasten it back into place with a screwdriver. Remember to shut down and unplug your device and ground yourself first.

Check Your Fan’s Connection

If you built your computer, you could check if the CPU fan is connected correctly. The connector on the motherboard that the CPU fan connects to is called the CPU fan header. The header is next to the CPU socket, and it is typically labeled “CPU_FAN.”

If you accidentally plug the CPU fan into the system fan header rather than the CPU fan header, your system will not detect your CPU fan because the CPU fan header is unused.

Stop Overclocking

fan spinning fast in computer

Overclocking dramatically increases system heat, and some fans cannot keep up. So, if you overclock your computer, resetting the clock rate to the default may fix any fan issues. However, if you want to continue overclocking, you may need to upgrade the fans to avoid unexpected shutdowns and overheating errors.

Move Your Computer

If your computer case is pushed against a wall or is exposed to a lot of direct sunlight, you may need to relocate your computer to avoid overheating.

You need to leave enough room around your computer to maintain proper ventilation. Avoid placing the case against a wall or other flat surfaces to optimize airflow. Keep your computer away from direct sunlight and other heat sources that increase system temperature. If you can, try to move your computer to a colder room.

Replace the Thermal Paste

thermal paste applied to cpu

If your CPU overheats despite your fan working correctly, you may need to inspect the thermal paste. If the paste looks old, dry, flaky, or cracked, you need to replace it.

Clean the old thermal paste and reapply a slight drop in the center of the CPU heat spreader. Then, place the heat-sink back on the CPU and ensure it is flat so that the paste spreads evenly.

Replace Your Fan

If nothing else works, you may need to replace the CPU fan to fix the error. If your computer or fan is new, the warranty may cover any repairs or replacement parts.

You can find new fans at most electronics stores or online, but ensure you get the right size and type for your computer. You may even want to consider upgrading your build with some RGB fans!

How to Fix CPU Fan Error on Boot

cpu fan in pc motherboard

If you come across the “Fan Not Detected” error while booting your computer, you might be facing an issue with your motherboard, power supply unit, or CPU fan. The error may also be caused by improperly configured BIOS settings or use of the wrong connectors on your motherboard.

To fix your CPU fan not being detected on boot, follow these easy steps:

  1. Check that the CPU fan is connected correctly.
  1. Open your computer case and examine the fan while the computer is turned on. Check whether the fan is spinning and operating as it should.
  2. Ensure that the CPU fan is plugged into the correct connector on your motherboard. You should find it close to the CPU on the motherboard, labeled CPU_FAN1. Using the wrong connector will prevent your BIOS from controlling your CPU fan.
  3. Remove the fan and try using it on another computer. If the fan spins and works properly, you may have a faulty connector on your motherboard.

How to Fix CPU Fan Speed Error

white fan in computer case

If your fan does not spin with the revolutions per minute (RPM) needed to cool your CPU, you will face a CPU fan speed error. The system sets the alarm for when the fan turns too slowly, typically below 600 RPM.

You can lower this setting in the BIOS and see if it solves your CPU fan speed error. To fix a CPU fan speed error, follow these simple steps:

  1. Shut down your computer.
  2. Turn it back on and press and hold the F1, F10,or the Delete key as soon as it boots up to enter BIOS. The key you need to press will vary between computers, so you should search for the appropriate key for your model online.
  3. Access Advanced Settings.
  4. Locate the CPU fan RPM alerts setting.
  5. Lower the default value from 600 RPM to 200 RPM, and save changes.
  6. Exit the BIOS and restart your computer.

After restarting your computer, your CPU fan speed error should be solved. However, if the alarm keeps appearing, you may have a hardware issue. In that case, you may need to replace the fan to prevent further damage to your components.

Frequently Asked Questions

closeup of amd case fan

How Do I Get Rid of the CPU Fan Error On My ASUS?

If you get a CPU fan error on an ASUS computer, you can get rid of it with these solutions:

  • Check that the CPU fan is installed correctly on the motherboard and that the screws are twisted in tightly.
  • Ensure the CPU fan cable is secured to the CPU_FAN connector instead of the CHA_FAN.
  • If you have a slower fan, your system may not detect it correctly. You can try to access the BIOS configuration of your computer and set “CPU Fan Speed Low Limit” to 200 RPM.
  • Update your BIOS to the latest version.

What Will Happen If CPU Fan Fails?

If your CPU fan fails, your CPU may overheat and ignite. Your motherboard and any other connected components may also become damaged. Idle and short-term computer workloads may not fry your hardware, but repeated use with a dead CPU fan will cause damage over time.

Is It Safe to Adjust CPU Fan Speed?

Adjusting the CPU fan speed is safe if you set it within the recommended manufacturer limits. If your fan speeds are too low, you risk overheating your computer. If your fan speeds are too high, your fan will wear out quickly. When adjusting your CPU fan speed, you need to monitor temperatures carefully to ensure everything is working correctly.

How Do I Know If My CPU Fan is Bad?

The first sign of a faulty CPU fan is a rattling or humming sound coming from your computer case. However, dust and debris may clog the fan and prevent it from working correctly. Another sign is your computer shutting down often, which means your CPU may be overheating due to a broken fan.


red rgb fans in computer case

You need to keep your CPU fan working, so your computer does not overheat. A CPU fan error warns you that the fan is not working correctly due to improper fan installation, fan damage, incorrect settings, or excessive dust.

You can try some common solutions, such as cleaning your fan and vent, checking your fan’s connection, replacing the thermal paste, or configuring your CPU fan RPM settings on BIOS.

If you enjoyed this guide on CPU fans, you could learn how to install case fans or test GPU fans!

Liam Weissman

A lover of MacBook Air and the Dell XPS line of laptops, Liam has been researching and writing as a guest blogger for numerous websites for over 10 years. Now, he blogs about tech trends, PCs, laptops, gadgets, and other emerging gadgets on FancyAppliance.com.

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