Check Engine Light Catalyst System Efficiency Below Threshold - Code P0420 P0430

Hi. I'm Mike from 1A Auto. We've been selling auto parts for over 30 years.

Hey, everyone. Sue here at 1A Auto. And today I'm going to show you Cat Efficiency code P0420. What it means and what a converter looks like internally, when it has low flow and gives the code 420. Here we have a converter with the honey comb inside, and the holes are partially clogged. This set off a Cat Efficiency code P0420. And that tells you the cause of the flow. So, say you have 30 honey combs and the air is supposed to flow through, this is probably cut down to 19 or 17. So, it doesn't have full flow.

Here we have a converter that's got age to it, but it's not clogged at all. There's no ports that are clogged. So, if you get that engine code P0420 and you're wondering what your mechanic is talking about and why you have to fix it, here's a little quick lesson on what it does.

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