Skip the auto shop - Our mechanics make house calls

Q: Should I replace or clean the catalytic converter?

asked by on

I was told I have a bad catalytic converter my car is not displaying any of the symptoms of bad converters but the engine check light is on so should I try a cat cleaner first?

My car has 165000 miles.
My car has an automatic transmission.

A: Hey there. The Check Engine Light can set i...

Hey there. The Check Engine Light can set if the catalyst efficiency is below threshold. There will be no visible symptoms at all, or change in engine performance, because the recorded "low efficiency" can simply mean that more pollutants are being emitted in the exhaust rather than destroyed or "converted" in the catalyst.

So to perceive a difference you would need a gas analyzer to measure what is going on with the tailpipe emissions. Before trying a catalytic cleaner (which itself is problematic if you have a particular product in mind, ask the manufacturer if they have any written, independent laboratory test evidence that it actually works. If they have nothing in hand to send to you, don’t waste your money), the pre- and post-O2 sensors have to be tested in order to determine whether the catalyst has really failed. There is a specific test strategy using output from those two sensors that has to be employed; an exhaust gas analysis is useful as well. If you need help having this checked, a certified professional from YourMechanic can come to your car’s location to diagnose the car and can replace the catalytic converter if necessary.

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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: "No bus" code

When the No Bus message appears in your instrument cluster, its usually an indication that there is a problem with the powertrain control module or the wiring to it. This is also very likely the cause of your no start...

Q: The ignition cylinder is locked in the On position

This sounds like something is broken in the steering column. A defective lock cylinder, or a seized ignition switch. It would have to be disassembled to see the problem. A qualified mechanic from YourMechanic can come out and diagnose the...

Q: In limp mode following a catalytic convertor repair. Have driven 70 mIles in limp mode.

The only purpose of the catalytic converter is to reduce exhaust emissions. The converter is within the exhaust system and functions as part of the vehicle's emission control system. Excepting only an unusual circumstance where the converter is physically plugged...

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 P0052 code means This code is seen when the Engine Control Module (ECM) tries to control 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...