Conditions For Setting DTC
WARNING: This page is about a different car, the 2002 GMC Sonoma and 2002 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The control module detects that the O2S is less than 50 millivolts for 1 second during a 3-second active test, for 3 consecutive 3-second active tests.