you stick some plastic explosives on it and run
After googling it is determined Code P0420 ( Catalytic converter effeciency below threshold)
Start with looking for a vacuum leak.
P0420 = Catalyst System Efficiency Below Threshold Bank 1.Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic converter needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.
it cant be fixed just tightend your gas cap harder
P0420 = Catalyst Efficiency Below Threshold (Bank1). Sounds like you probably need to replace the Bank 1 (drivers side) Catalytic converter.
How do you fix a p0420 bank 1 on a 05 dodge stratus
Reset the code. If comes back check o2 sensor and cat
Replace the catalytic converterReplace the catalytic converter
Catalytic converter failure. Replace the catalytic converter.
DTC P0420 = Catalyst System Efficiency Below Threshold (Bank 1)You can drive it but it would be wise to have the vehicle checked out as soon as possible. Putting this off could cost you more in the long run. If you have other codes preceding code P0420 fix them in order as they come up before you attempt to fix P0420.
Fix any exhaust leaks, test/replace the oxygen sensors, replace the catalytic converter.
Replace the catalytic converter.Replace the catalytic converter.