How to fix P0420 code: “Catalyst System Efficiency Below Threshold.”
If you’re searching for how to fix the P0420 code, your problem is most likely related to issues with the catalytic converter. Since the catalytic converter is very expensive, before you replace it, check issues with other components like the oxygen sensor, the muffler, the exhaust pipe, the manifold, or the oxygen wiring. The catalytic … Read moreHow to fix P0420 code: “Catalyst System Efficiency Below Threshold.”