Conditions For Setting DTC
WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The Heated Oxygen Sensor 1 (HO2S) 1 voltage is less than 300 mV for 10 seconds.