Conditions for Setting the DTC
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
P2271
The ECM does not detect an HO2S voltage less than 150 mV before accumulated mass air flow exceeds 550 grams.
P2273
The ECM does not detect an HO2S voltage less than 100 mV before the accumulated mass air flow exceeds 76 grams.