Service engine light on Code PO420 catalyst system efficienc

Tiny
STEVERIX
  • MEMBER
  • 1942 CHEVROLET LUMINA
My 1997 chevy Lumina 3.1 engine Won't pass e check. Code PO420. Catalyst system efficiency below threshold. Bank 1. Is this somekind of sensor? What needs to done to repair this problem and is it costly? How hard will this be to repair? It has 112K miles. Thank you very much
Thursday, November 8th, 2007 AT 8:47 PM

1 Reply

Tiny
DENNYP
  • MECHANIC
  • 1,824 POSTS
Sounds like you could possibly have a restricted or damaged catalytic converter.A quick check is to give it a couple whacks with the heel of your hand and listen for a rattle noise in it.(Make sure the converter isn't hot) Also, check to make sure you have exhaust flow from the tailpipe.
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Friday, November 9th, 2007 AT 9:27 PM

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