⭐About DTC CODE P0420 / P0430
If your converter needs to be replaced dueto an emissions error/ problem in your engine turning. This must be corrected before installing the new converter.
Incorrect spark plugs
Rich or lean fuel mixture
O2 sensor is no toperating correctly Fuel injector problems
High engine oil orcoolant consumption
EGR problem
Leaking exhaust system
lmproper ignition timing
Damage in theinternal engine
Any one of the above can cause the DTC Codeeven if you are installing a brand new converter