Toyota solar a 2001 4 cly has a code po420 what is wrong

Question

What needs to be done to fix this po420 code

Answer 1

P0420 Catalyst below threshold

Catalytic convertor do wear out over time and usage and mileage, If the engine performance of the engine is not in fuel control or balanced the catalytic convertor has to work much harder, Do a MAF (mass air flow ) cleaning with a throttle body cleaning and replace spakrplugs if worn (or tune up is due) and see if this helps.