A post-catalytic converter oxygen sensor should ideally:

A post-catalytic converter oxygen sensor plays a critical role in monitoring the efficiency of the catalytic converter and ensuring optimal fuel mixture adjustments. After the exhaust gases have passed through the catalytic converter, the primary function of the post-catalytic converter oxygen sensor is to provide feedback on the catalytic converter's performance by measuring the amount of oxygen in the exhaust gas downstream of the catalyst.

Ideally, this sensor should remain steady at approximately 0.45V, indicating that the catalytic converter is effectively performing its job of converting harmful emissions into less harmful substances. A stable voltage around this level means that the exhaust gases have a balanced oxygen content, which signifies that the catalytic converter is functioning correctly in its role of reducing emissions. This consistent reading helps the engine control module (ECM) ascertain that the vehicle is running efficiently with minimal unnecessary emissions.

In contrast, significant fluctuations in voltage would suggest that the catalytic converter is not functioning effectively, as the oxygen levels in the exhaust would be inconsistent, indicating incomplete combustion or perhaps a failure of the catalytic component itself. A continuous high voltage might imply an overly rich mixture or malfunctions, while variations with engine load are not typical behavior for a post-catalytic converter sensor, as it should reflect a more stable state after