After using catalytic converter cleaner, results are not instant for every vehicle. The product needs normal driving time to move through the fuel and exhaust path, and the outcome depends on the actual cause of the issue.
Reasonable expectations
- You may need to drive through a normal fuel cycle before judging the result.
- A returned check engine light means the vehicle is still seeing a monitored issue.
- Cleaner cannot repair broken parts, leaks, wiring problems, or failed sensors.
If the code comes back
If P0420 or P0430 returns, read why a check engine light comes back after clearing a code and how P0420 differs from a bad oxygen sensor.
Product link
For routine fuel-tank use, see Tokbolt Catalytic Converter Cleaner.
Tokbolt guides are for product education and routine maintenance context. They are not a replacement for vehicle diagnosis, professional service, or local emissions-rule guidance.