Skip the auto shop - Our mechanics make house calls

Q: How do you know if catalytic converter is bad

asked by on

Engine light on Dealer said catalytic converter No problems with acceleration no prob with gas mileage no smell no noise How do you know for sure it's the problem Engine light off after 2 weeks since diagnosed

My car has 176000 miles.
My car has an automatic transmission.

To begin with, 170 thousand miles is just about the right time for the catalyst on a civic to start acting up. Your car is equipped with two oxygen sensors to monitor the catalytic converter function. The reaction that takes place in the catalytic converter consumes oxygen, so if the converter is working, the exhaust oxygen content will be lower coming out of the converter than it was going in. When the engine controller senses that the difference in the oxygen levels is not great enough, it will present a fault and light the check engine light. The engine controller performs a catalyst test once per drive cycle. If the catalyst passes the test a certain number of times the Controller will turn the light off. When the catalyst is in early stages of failure, it may pass the test sometimes and fail it at others, so you may have the check engine light going out for a while then coming back on. But the code is stored, so whether the light is on or not, the scanner will pick up the catalyst efficiency code. A bad catalyst may not affect the way the car runs at all. But you won’t be able to pass inspection with a bad catalyst, so sooner or later it will have to be changed. If you contact Your Mechanic,they can send a technician to your home or office to take care of the catalyst replacement for you.

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: Going through too many batteries

If you have replaced your battery four times since 2012 then you are having an issue with your charging system that should be diagnosed. There are a few Technical Service Bulletins(TSB) that could address your issue. The first two are...

Q: Hi, why is it heavy to steer my wheel? But before that I am having problem with my front left tire, its always low on pressure.

When either of your two front tires are low on air pressure, this will cause the steering to be tough to steer depending on how low the air pressure is. Less air in the tire creates more drag on the...

Q: Passenger window stopped working

Hello. The most likely cause of your new window not working is the window motor and/or window regulator. In some rare cases, some of the wiring going to the window motor could be damaged as well, although this is...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...