The TX2(JetPack 3.0) can't access FAN

I got a problem with FAN on my custom base board. But it works fine on the developed board.
It is nothing on the pwm output pin.The error is shown below:

nvidia@tegra-ubuntu:~$ sudo ./
[sudo] password for nvidia:
Can't access Fan!


Hi Hongsheng,

What’s the different of your custom carrier board compared with origin carrier board? Maybe that’s caused by device tree issue, bot really sure, but you can refer to

Besides, could you try JetPack3.1/R28.1 to confirm again?


There is nothing between the two circuit of FAN but the ‘enable’ signal,see to attachment for custom carrier board.

I can’t use the JetPack3.1/R28.1 due to some reasons.

Does any other circuit needed for FAN ? It works well on the origin carrier board.


Hi, please measure the signal first.

  1. If the 1.8V, 5V are normal
  2. If the ‘FAN_TACH’ will be driven to low when fan attached.
  3. If the ‘FAN_PWM’ output waveform is normal when set it output PWM signal, and what’s the waveform on pin 4 at this time.
  1. The 1.8V,5V are both normal
  2. The ‘FAN_TACH’ will be driven to low when fan attached.
  3. The ‘FAN_PWM’ output is drived high on the custom carrier board all the time,and nothing on pin 4.

The ‘FAN_PWM’ output waveform is normal with or without FAN, and ‘FAN_TACH’ is normal with FAN on the origin carrier board.



Have you clarified the cause and resolved the problem?
Any result can be shared?


I had a SD card installed when installing Jetpack, some how the Jeston was failing to read from the debug file system. Re-flashing the Jetson without the SD allowed the fan to start. Hope this helps, I couldn’t find a good answer but I had this with Two Jetsons and this seem to fix them.