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P0420 Chevy Cavalier

Model: Chevy Cavalier Fault Code: P0420 Posted: 2008-04-10 21:23

Ok when this code came up from a diagnostic test I was told I need a new CAT. No problem! I bought a good one from ebay and had the shop install it. They reset my light and 100 miles later it came back on. They did another test and told me my CAT was defective I need another one. Trusting the shop I had them order a reliable one. They installed it and cleared the CEL. 100 miles later the light came on showing P0420 problem again. They replaced both o2 sensors and still didn't work. What would my problem be? The CATs I was installing were after market. Could be it I need the OEM from the dealership?

Related fault codes

P0420

Comments (3)

Anonymous 2008-04-11 05:09

software update? regardless i think the shop you're at is in over ther head. a scope and some insight can determine if your new cats are defective. alot of aftermarket brand are very unreliabe and poor quality

Anonymous 2008-04-11 15:09

Software update? On my end or the shops end? If it possible my computer is just messed up? I need to pass Pennsylvania inspections without this code being a problem.

Anonymous 2008-04-11 19:26

The cars software/. how would your pc softwares fix that? I'd still suspect the quality of your replacement converters. What brand does your usual mechanic recommend. Is it different then your e-bay choice?