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.

When the AIR pump turns ON during closed loop operation, the HO2S voltage does not go below 222 mV for 0.9 seconds.
When the AIR pump turns ON during closed loop operation, the short term fuel trim does not change more than a predetermined value.