The PWM GPIO does not function anymore

I could run PWM GPIO before.
But it does not function anymore. I can run the python code which opens a website which I can interact with. After I hit the correct key, a signal would be sent to Jetsonnano and it should send the PWM GPIO signal to the pump. But this does not happen anymore, what can I do?
I have reflashed the microSD card 2 times and it doesn’t work. I even did the same procedure and run the same code on the other Jetsonnano and it works well. So I now suspect that there might be some fatal change happened to the board, what can I do not?
Thanks in advance for anyone who would like to help me! I

There is no update from you for a period, assuming this is not an issue any more.
Hence we are closing this topic. If need further support, please open a new one.
Thanks

What code are you reffering to?
Is it something official from NVIDIA?