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Journeyman III

cpu fan error, please check

I purchased this upgrade kit from Megekko ( - Megekko Upgrade Kit X470 Gaming Plus 2700X 16GB )

and after i turn on my pc, it gives a error called ''CPU fan error, please check. 

My specs are:

CPU : AMD RYZEN 7 2700x

Motherbord : MSI X470 Gaming plus

GPU : MSI Geforce GTX 1060 6gb

Memory  : Corsair DDR4 Vengeance LPX 2x8 3200 Mhz

Power supply : Corsair RM550 (550W)

I really dont know what to do. Please help.

11 Replies
Adept III

Is the processor fan plugged in? What cooler do you use? If the fan is running properly you should be able to press F1 or whatever to enter the BIOS. Then it should boot after you exit from BIOS if you have a drive with an operating system.


Yes it is plugged in and i use the AMD cooler that comes with the ryzen 7 2700x. Also the cpu is not getting hotter than 50℃ so the fan works i guess. 

Adept II

I had this and it was just user error. I had plugged the fan into the wrong socket on the board. Make sure the fan is plugged into number 1 socket :-)


Number 1 socket?


On my old Asus Prime x470 when i plugged it into a different header/socket on the motherboard it would give me a CPU fan error. I had to plug it into number 1 header socket for the error to go away.

Adept III

check CPU_Fan Header connects to CPU FAN

disable in BIOS FAN FAIL Warnings

Set Fan to Auto Mode in BIOS

Reset BIOS to default values

Flash BIOS using a USB Drive


From your Motherboard's Manual on where the CPU Fan connection is on your motherboard:

NOTE: Make sure you have all the CPU Power connectors connected to the Motherboard from the PSU in the upper left corner.


Hi all,

I would like to re-open this case. Every time the PC is restarted the error message about "CPU Fan Error" appears.
First of all, my hardware components are as follows:

  • OS: Windows 10 Pro, Version 10.0.19042 Build 19042, x64
  • CPU: AMD Ryzen 7 2700X Eight-Core Processor, 3700 MHz, incl. Wraith Prism Fan
  • RAM: G.Skill, F4-3000C16-8GISB, CL16-18-18-38, Ranks: DUAL, Max Bandwidth: DDR4-2133
  • Mainboard: MSI B450-A PRO MAX (MS-7B86)
  • BIOS-Version: M.A0
  • BIOS-Date: 26.11.2020 (Note: BETA BIOS version (last version; M.C1) tested, but failure is still available)
  • Graphic Card: ASRock Radeon RX580 8G GDDR5
  • Power Supply: PURE POWER 11, 600 W / 3.3 V - 25 A / 5.0 V - 18 A


I assembled the PC myself. The components were delivered at the beginning of December. After finishing the assembly, the PC was powered on and run for about 2 minutes. CPU fan (CPU_FAN) and case/system fan (SYS_FAN1 and SYS_FAN2) worked as expected. No OS installed at this time. Windows 10 Pro installed one day later.

Sporadic failures of the CPU_FAN were observed right after booting the PC - OS already loaded. SYS_FAN1 and SYS_FAN2 did not show any sporadic failures. The failure behavior showed up as follows: The CPU_FAN and the corresponding RGB lighting turned off for a short time. The failure duration of the CPU_FAN was less than one second (video recorded). After this failure the CPU_FAN was active again for X seconds (in some cases > 10 seconds) until the next failure:
Example: CPU_FAN: X seconds on, < 1 second off, X seconds on, < 1 second off, etc.

Using the CPUID HWMonitor program, I was able to monitor the speed of the CPU_FAN as well as the CPU temperature.
At the time of the failure, as expected, the rotation of the CPU_FAN decreased and the CPU temperature increased by about +5 °C.

First action:
Mainboard: MSI AMD Motherboard B450-A PRO MAX (MS-7B86)
BIOS updated (M.A0). The BIOS version 7B86vMA was downloaded from the MSI web page. The BIOS was updated via M-Flash.

Reboot: CPU FAN FAIL detected by BIOS.
Sporadic CPU_FAN failures still present.

Second action:
MSI Live Updater 6 installed.
Using the Liver Updater 6, the following items were downloaded and installed:
* Realtek HD Universal Drivers (Version 6.0.9071.1)
* AMD Chipset Driver (Version
* Realtek PCIE Network Drivers (version 10.42.0526.2020).

Reboot: CPU FAN FAIL detected by BIOS.
Sporadic CPU_FAN failures still present.

Third action:
Radeon Software Adrenalin (version 2020-20.12.1).
Unfortunately, it did not show which drivers were installed with the Radeon Software Adrenalin.

Reboot: CPU FAN FAIL detected by BIOS.
Sporadic CPU_FAN failures still present.


Additionally, if the PC is about half an hour in operation, no more CPU_FAN failures were observed. It seems to me that these failures only occur during a "cold start". "Cold start" is, when the PC was not in use for several hours. The CPU_FAN error messages, however, were still present at every restart - regardless of whether it was in operation for longer or during a "cold start". 

NOTE: Please do not misunderstand, the sporadic failure is still present during every "cold start".



For several days I am struggling to solve the following problems:

  • CPU_FAN error message on every reboot - I do not want to disable the warning in the BIOS. I mean, if BIOS gives me the message that it detected a CPU_FAN problem, so I can take action.
  • Sporadic CPU_FAN failures.





Thanks for the long content, but it just a CPU cooler error, the first check should be the connection with the mobo, if the connection is OK but the fan still not working, Perhaps need to buy a new CPU cooler .


Thank you for your answer.

The CPU_FAN connector and the other connectors are installed in their correct positions.

I have got a used CPU fan/cooler (COOLER MASTER DL5-8FDSC-F1-GP 090920YD4) today. I have disconneted the CPU_FAN connector of the WRAITH PRISM from the mainboard and installed the used cooler. Sporadic failures of the used cooler was not noticeable. But even with the used cooler the error message still appears at every restart - I repeated this 3 times and the error message appears every time.

I have re-connected the WRAITH PRISM again.

From this point it can be concluded that not only the CPU_FAN WRAITH PRISM but also possibly the mainboard is defective? How can I exclude that the mainboard has an error?




Hi All,

I have to correct my statement about "cold start". The misbehavior happens continuously independent of whether the PC has been running for almost an hour or has just been started up. I hoped with a reboot that the misbehavior would get better.  Thereby I removed the 4-pin RGB cable and then rebooted the PC.

There are no sporadic CPU_FAN failures noticeable, but the CPU_FAN error message still appears when booting the PC.

I tried a new attempt to control the RGB, for this time via USB connection.

No sporadic CPU_FAN failures, CPU_FAN error message still appears.
The RGBs of CPU_FAN can be controlled by AMD Cooler Master Tool.

In my point of view, there are two possible causes for sporadic CPU_FAN failures:

  1. I assume that the RGBs of the CPU_FAN have a malfunction if the CPU_FAN is connected via the 4-pin RGB cable to mainboard. This likely causes a collapse of the complete CPU_FAN voltage and that in turn could explain the sporadic CPU_FAN failures.
  2. The other possibility is that the mainboard does not work correctly or does not control the CPU_FAN and associated RGBs correctly if RGBs of CPU_FAN are connected via 4-pin RGB cable.

As mentioned in previous post, I want to exlude that the mainboard is the actually cause for the sporadic CPU_FAN failures. Therefore, is there any opportunities to check the CPU_FAN connector and JRGB1 connector on mainboard?

Thank you in advance!