XPS 9560 CPU FAN issue

I have an issue particularly with CPU fan. As soon as I hit my power button it keeps constantly spinning at full speed with no change no matter if I'm in Windows or BIOS. No issues with GPU fan. CPU and system temperature is 40-45 °C. This started suddenly by turning on the laptop on random summer day this year (2 weeks after my warranty expired). All drivers are up to date, bios downgrade didn't help. I ran an ePSA diagnostic and it threw an error with code 0511.
I opened the laptop and swapped the CPU and GPU fan for few second test and even GPU fan (plugged to CPU fan's port) did the same thing, so I assume there is no issue with fan itself.

Can anyone advise, please?