P0420 OBD2 code indicates that the efficiency of the catalyst system is below the threshold

How does the P0420 OBD code affect the performance of the car?

The P0420 OBD2 code indicates that the efficiency of the catalyst system is below the threshold. But that doesn’t necessarily mean you have a bad catalytic converter.

The code will happen if the upstream and downstream oxygen sensors indicate similar readings. They won’t match if the catalyst system is within a proper threshold.

The car’s performance is only affected if the catalytic converter is extremely clogged, reducing fuel efficiency. You’ll feel it because it will be as if you have a clogged fuel filter, and the engine will tend to stall out under heavy loads. 

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* Indian Roadie Knowledge Hub 

* Catalytic Converter  

* Indian Roadie Maintenance Issues