High precision electrochemical CO sensor initialization fails without LMPEN pin grounded

TECHNICAL SUPPORT Sensors & Modules
1

Customer:

I’m trying to set up the High precision electrochemical CO gas sensor breakout using its PCB with Arduino sample code (singleSensor.ino) on a TinyPico ESP32. The code uploads successfully, but the sensor initialization fails every time. I’ve tried switching cables and using different TinyPico ESP32 boards, but the problem persists.

Originally submitted via email support on 24 September 2025. Migrated to the forum for community visibility.

2

Soldered Support:

Did you connect the LMPEN pin to ground? Check the documentation for setup instructions: Electrochemical Gas Sensors – Single sensor measurement example | Soldered Documentation

If you’re still having issues, please share any error codes, compilation errors, or Serial monitor output.

3

Customer:

The issue was resolved - I had forgotten to connect the LMPEN pin to ground.