Q: P0420 - CATALYST B1 DETERIORATION

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Recently replaced the charcoal canister. The engine would stall after refueling and it would give off a heavy fuel smell when parked in the garage. Problem was solved the car is running great. A few weeks later check engine popped up P0420 - CATALYST B1 DETERIORATION. Are the two related? Could this be because of a difference in air fuel ratio readings picked up by the sensors?

My car has 140000 miles.
My car has an automatic transmission.

Hello - it is possible the 2 problems are related, but likely only over a long period of time. The P0420 code is a "low efficiency catalytic converter" for Bank2 - which include cylinder 1. And yes, that warning is calculated between the pre-cat O2 sensor, and the post-cat O2 sensor. It is possible the catalytic converter has become clogged or ineffective overtime due to excessive fuel vapor contamination, but the evap emissions system should be taking care of this. I would recommend having a Catalytic Converter Replacement Service completed by a mobile, professional mechanic, such as one from YourMechanic, to resolve your current problem.

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