Skip the auto shop - Our mechanics make house calls

Q: P0420 - CATALYST B1 DETERIORATION

asked by on

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.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Check Engine Light is on - trouble code P0420

As you may know, trouble code P0420 relates to the inefficiency of the catalyst system, which detects the presence of oxygen in the exhaust gases. This can be caused by failing O2 sensors that need to be replaced. This can...

Q: Getting error codes P0599 and P0171. Ive cleaned the O2 sensors but have no idea where to go from here.

Hello. Code P0599 is the code for an issue with the thermostat heater control circuit, while P0171 is for a lean condition on bank 1. P0599 is set when the computer detects that there is an issue with the electronically...

Q: The P0010 error keep coming up and my car keeps jumping, and turning itself off and on while I drive sometimes.

Hello, thanks for writing in. If you took your vehicle in for repairs, and it was returned with a check engine light then I would immediately return to the shop and have them take care of the issue. If the...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...