Post Catalyst HO2S

WARNING: This page is about a different car, the 2015 Jaguar XF, 2014 Jaguar XF, and 2013 Jaguar XF. However, it is still accessible from the selected car via links, so may be relevant.

The post catalyst HO2S is located in the exhaust system between the catalytic converter and the flange connection for the center section exhaust. The rear HO2S is used by the ECM to monitor the oxygen content of the exhaust gasses leaving the catalytic converter. The ECM can use this information to check (when the conditions for catalyst diagnostics have been met) for correct operation of the catalytic converter. The ECM uses the information from the rear HO2S to enhance the signals from the front HO2S.

The rear HO2S is similar in its construction to the front HO2S with the exception of the output signal to the ECM. The output signal is a binary signal where the amplitude of the signal curve changes considerably when the oxygen content in the exhaust gasses changes. The oxygen content of the exhaust gasses leaving the catalytic converter are measured by comparing it with ambient air drawn into the HO2S.