CPU Fan Not Recognised

[DylanTech]

I have a Phanteks Enthoo Pro case with a PWM hub, powered by the SATA cable from the PSU. This hub derives the PWN signal from the CPU_FAN connector, and all the fans connected to the hub derive their speed from the same 3-pin fan connector which is what my CPU fan is connected to. My problem now is whenever my PC boots, the BIOS is unable to recognise the CPU fan (even though it is connected to the PWM hub) and I need to exit the BIOS to use my PC. Does anyone know how I can fix this problem? I do not want to have to plug my CPU fan into the CPU_FAN connector because then I will lose complete functionality to the PWM hub as it requires the CPU_FAN connector to operate, consequently I will lose two of my fans. Also, this setup is stopping Fan Xpert 4 from being able to read the RPM of my CPU fan. Any help would be much appreciated. I have an ASUS ROG STRIX Z390-F GAMING motherboard.

Edited January 10, 2019 by DylanTech
Added my motherboard at the end.

[LogicalDrm]

The main problem is that fans on the hub have different rpms/specs. And hub only gives out one fans speed to mobo, the one connected to header with rpm pin connected. You can disable CPU_FAN warnings from BIOS, letting you boot without issues. Your mobo has 5 PWM controlled headers. CPU_FAN and CPU_OPT are controlled by same chip, meaning that fans will use same curve/control scheme. CHA_FAN1/2 are on their own controllers, same with M.2_FAN. You can try by having CPU fan/s on CPU headers and using CHA header for hub.

[WoodenMarker]

The pwm hub just needs a pwm signal and not necessarily be plugged into the cpu_fan header. The F1 error at boost can be disabled in the motherboard settings. FanXpert's tuning may needs several tries before getting it right. I recommend using reading the rpm from the fan with the lowest rpm off of the splitter.