Wideband stuck on 19.7

I bought the spartan 2 wideband controller in 2020 with Bosch LSU 4.9 but now turning the car on, the AFR readings go from 10.30 to 16.6 and stays fully at 19.7 even when the car is properly tuned. The sensor is angled in the exhaust and I have it set to turn the controller on 30 sec after the engine is already running. Did my sensor just died? How can I make sure it’s just the sensor?

This is the troubleshooting guide, Spartan 2 Troubleshooting Guide - #4