P0420: Why It Is Rarely Just the Catalytic Converter
What the ECU is really measuring when it stores P0420, the cheaper faults that produce an identical reading, and how to check them in order before buying a converter.
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P0420 — Fault codes explained properly, what each one usually costs to put right, and how to check it yourself before anyone quotes you.
What the ECU is really measuring when it stores P0420, the cheaper faults that produce an identical reading, and how to check them in order before buying a converter.