Conditions for Setting the DTC
WARNING: This page is about a different car, the 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
If the ECM detects that the rear HO2S 2 voltage is more than 740 mV for more than 100 seconds, then an intrusive test is performed. The ECM will lean the fuel mixture up to -7 percent and then wait for 10 seconds at -7 percent. If the ECM detects that the HO2S 2 voltage is still more than 740 mV, the ECM then tests the HO2S 2 at the next decel fuel cut-off. If the ECM detects the HO2S 2 voltage is more than 202 mV after 4 seconds in decel fuel cut-off, this DTC sets.