Conditions for Setting the DTC
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
The PCM detects that the HO2S 1 voltage is less than 79 mV for more than 51 seconds.
OR
The PCM detects that the HO2S 1 voltage is less than 600 mV during power enrichment (PE) mode for more than 7.5 seconds.