Conditions For Setting DTC
WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.
If the AIR pump turns ON during a closed loop operation and the HO2S voltage does not fall below 222 mV for 1.3 seconds; or if the AIR pump turns ON during a closed loop operation and the short-term fuel trim does not change more than a predetermined amount.