Conditions For Setting DTC
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
The PCM detects that the HO2S 2 voltage remains within 74 mV of the bias voltage, about 450 mV, for a longer amount of time than necessary. The amount of time ranges between 100-130 seconds depending on ECT at start-up, and the average Mass Airflow (MAF) since start-up.