Need help-MG811 co2 sensor module- sandbox electronics


I have been trying to connect the MG811 CO2 sensor module with Arduino Uno. I used the following datasheet:

I have connected the Vout to pin A0 and For the BOOL pin, I connected a 10 K pullup resistor and connected to Pin A2. Ground pin is connected to ground. I am using external 9V power supply for the heater. When I run the code provided, it doesnt work. Can somebody help me?

Thanks Zubeida

What didn’t work? The module, the arduino, the upload, or serial communication? Did you you get any error messages?

I am getting continuous output on the serial monitor that BOOL IS HIGH, CO2 CONCENTRATION is -18436, and SEN-00007 is 0.00 V :(