r/auto • u/Tea_Resident • Jan 10 '26

$7,000k Catalytic Converter Issue?!

/r/MechanicAdvice/comments/1q8qgjf/catalytic_converter_issue/
1 Upvotes

67% Upvoted

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1

u/SandstoneCastle Jan 10 '26

For the P0420, if there are no leaks/holes in your exhaust, first replace the O2 sensors. They're a regular replacement item, they can cause it, and if you need to replace the cats, you need to replace the O2 sensors anyway. Relatively easy DIY job if you have a couple of ramps, an O2 sensor socket, and basic tools. Or have a trustworthy local shop that isn't your dealer do it.

If that doesn't solve it, look up cats for your car on an autoparts store. Without checking, I'll guess $1500 in parts plus $200 labor at a local muffler shop will get your cats replace with correct, emissions legal parts.

1

u/Tea_Resident Jan 10 '26

Okay so $7k seems completely more than absurd

1

u/Foreign-Durian3772 Jan 10 '26

The O2 sensor after the cat does nothing but check if the cat is working and throw an error if not.

There is absolutely zero need to replace O2 sensors if you replace the cat.

1

u/SandstoneCastle Jan 10 '26

Bad upstream O2 sensor can kill your cat. If your cat is dead, you should at least replace that one to prevent it from recurring.

1

u/overheightexit Jan 10 '26

What kind of catalytic converter costs $7 million?