Conditions For Setting DTC

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

ECM detects that the affected HO2S 1 voltage is 60-400 mV when the same bank HO2S 2 voltage is greater than 499 mV for at least 10 seconds.
ECM detects that the affected HO2S 1 voltage is 538-1080 mV when the same bank HO2S 2 voltage is less than 104 mV for at least 10 seconds.
ECM detects that the affected HO2S voltage rises during 16 out of 24 ON and OFF cycles of the HO2S heater.