The BTA version of the CO2 Gas Sensor is not supported by the original Go!Link. (The original Go!Link label simply says Go!Link, like the one shown below, while newer versions say Go!Link by Vernier.)

CO₂ Sensor

Original Go Link

The issue is that the original Go!Link does not supply enough current for the sensor to ID correctly. You will need to use either a newer version Go!Link, a LabPro, or a LabQuest interface (any version) with a CO2 sensor.

Note: The older style CO2 sensor (0-5,000 ppm range) is not supported by any version of Go!Link.