What's involved
What this repair actually is.
A P0420/P0430 code does not automatically mean the converter is dead — bad oxygen sensors, exhaust leaks, or engine misfires can trigger the same codes. We scan the vehicle, compare upstream and downstream sensor data, check for restriction with a backpressure test, and confirm whether the converter itself has failed or something cheaper is the real cause.
Symptoms
How you can tell.
- Check engine light with a catalyst efficiency code
- Rotten egg (sulfur) smell from the exhaust
- Sluggish acceleration or loss of power
- Rattle from under the middle of the car
- Failed emissions inspection
If you delay
A clogging converter chokes the engine, hurts fuel economy, and can overheat enough to become a fire risk in severe cases.
Educational estimate. Real pricing depends on your vehicle, the inspection, parts availability, taxes, and shop rates. Use this as a guide while you shop quotes.