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.

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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Should I replace or clean the catalytic converter?

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: Q: Transmission "popping" out of gear

This may suggest failing transmission synchros. As you may know, when a clutch drags, it is not letting go of the disk fully which overloads the synchros and burns up the friction surfaces quickly. Synchros work by speeding up or...

Q: My engine is slightly knocking. I need to replace oil pump. Will it be worth replacing? Will the engine be okay after replacment?

It is very likely that the engine could be bad based on the sound. Most likely the oil pump going out caused other damage. On an older vehicle such as a 1992, the cost if an engine replacement may exceed...

Q: I had the catalyst converter replaced last year. Now the Check Engine Light is on again for O2 sensor. What do I do?

You may want to have a professional inspect the catalytic converter. When the Check Engine Light comes on for this, it does not necessarily mean that the catalytic converter has failed. This may be related to many other things as...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.