P0420 Chevrolet -

Question

I have a 1999 Astro van,P0420,changed out O2 on bank one, old one had white ash residue on it. Failure code came back. I was looking around top of motor for a vac. leak and found a coolant leak between intake & head @ #5 cylinder, I suspect coolant might be leaking into intake runner and going out exhaust. could this set check engine light with failure code P0420? [email protected]

Answer 1

Yes it does .  it can also have coated the catalytic convertor , if you just replace the catalytic with out fixing the root cause you end up replacing the catalytic convertor again..