Circuit Description: Notes
WARNING: This page is about a different car, the 2004 Suzuki Aerio. However, it is still accessible from the selected car via links, so may be relevant.
ECM monitors oxygen concentration in the exhaust gas which has passed the three way catalytic converter by HO2S-2. When the catalyst is functioning properly, the variation cycle of HO2S-2 output voltage (oxygen concentration) is slower than that of HO2S-1 output voltage because of the amount of oxygen in the exhaust gas which has been stored in warm up three way catalytic converter and three way catalytic converter.