Grove Pi + CO2 Sensor MH-Z16

Question

I am using the Raspberry Pi 3 B model with Grove Pi + (1.2.2) firmware and Raspbian for Robots Image. I plugged in an MH- Z16 CO2 sensor in the RPISER port, and I'm trying to execute the code that is available on Dexter Github

I am having the following issues:

The first time I tried the code, it worked, but it got very strange results, always out of range and strange temperatures. He calls the sensor every 18 seconds.

Now that I have connected the sensor in the RPISER port (with rpi on), the raspberry pi freezes. If I try to restart it, it does not restart until the sensor closes rpi. I do not know what is happening and how to solve this problem. Sometimes rpi does not freeze, but the mouse and keyboard suddenly stop working. If I try to restart rpi using the sensor, rpi does not restart, it gets stucks.

Can I use this sensor in a different port?

Any help or any hint?