I recently moved some 3000 miles, dragging my PC with me. When I arrived I found that my old B450 Tomahawk (OG) had taken a hit to the CMOS battery. So I picked up a used Asus B350-F. It was sold with a note that the first x16 PCIe tab lock was broken, which wasn’t a big deal for me. So far so good.
So I get my CPU (3700X) installed, and was a bit nervous about booting it up since if the BIOS was too old, it’d probably boot to a black screen. But no, it booted fine. But then I started running into an issue. It kept reporting a CPU Fan Error and then prompting me to press F1 to enter UEFI. I do not have a CPU fan in the normal sense. I have a Corsair H60 AIO liquid cooler. And even though I’ve tried hooking the radiator fan up to the CPU_FAN and CPU_OPT headers, I still keep getting this stupid CPU Fan Error.
I finally did an end run around the issue by disabling the ‘Press F1 on error’ option in the EFI. But it still pops up every time I boot, though I can at least now get into Linux and Windows. Any thoughts on what might be causing this? Is it just a defective mobo/sensor?
If there’s a fan connector for the pump I’d try to use that to clear the error. Maybe the tachometer line for the CPU fan is broken and confusing the motherboard. What I’d try next is a BIOS update, if you feel like it’s worth trying to resolve the issue.
There is a dedicated AIO_PUMP header (which the H60 is plugged into), along with CPU_FAN and CPU_OPT, not to mention a few CHA_FAN headers. I’ve tried hooking the 120mm radiator fan to both the CPU_FAN and CPU_OPT headers, but still keep getting the error.
On the fence about updating the BIOS. This particular board doesn’t have the flashback feature that most modern Asus boards do, so it’s a little riskier than normal to flash.
I’ve had Asus boards in the past that through CPU Fan errors with AIO’s even though the fan was spinning a cooling fine. My solution was disable/ignore the CPU Fan in Bios. Ran a it that way for years with no problem.
There is an option to disable the CPU fan monitoring in the “Q-Fan” settings. But in spite of disabling it, I’m still getting the error.
I guess it doesn’t really matter since I can automatically boot past the error. Still, there’s some compulsive part of me that wants a completely clean boot process.
If you only connect the CPU_OPT you’re bound to get the CPU fan error since it piggy backs off the CPU_FAN. But this is beside the point.
Do you have any other fan that you can connect to the CPU header just to make sure it’s not the fan acting up? I don’t think that’s the real issue, but it might be worth trying.
Totally get it. If it’s risky it’s not worth doing to just get rid of that error that can be ignored anyway.
Ah a detail I almost forgot to mention. The reason I plugged the radiator fan into CPU_OPT was because the CPU_FAN header had a bent pin. When I started getting the CPU Fan Error, I ‘unbent’ the pin and plugged the fan into that header. Of course that did not resolve the problem, but it could well be that there was also less obvious damage to the board.
As a completely unrelated side note, I’ve been really pleased with the audio quality of this board, esp. when compared to my original Tomahawk.