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Catalist 420 code?


Old 01-15-2009, 01:20 AM
caggi is offline
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Question Catalist 420 code?

"MIL" (ck eng) light is on for a PO420 DTC? Do I need a new cat? I would appriciate anybody who could help. thanks
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Old 01-15-2009, 09:20 AM
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P0420 is catalytic converter efficiency below minimum specs.

Probably time for a new cat, but have you changed anything else? it could also be a dirty O2 sensor. you can clean them with electric parts cleaner. you can also use carb/choke cleaner if you're careful
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Old 01-15-2009, 06:35 PM
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You could also fill in the specs about your truck when you register! And it's probably time for a new lower intake gasket.
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Old 01-15-2009, 07:02 PM
xskylinedx is offline
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Just remember if you do in fact need a new cat check out summitracing. I picked up a
hi flow stainless steel magnaflow cat for under $100.
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Old 01-15-2009, 07:49 PM
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420 Hmmmmmmmmmm ?? - Not enought THC in your system
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Old 01-16-2009, 06:35 PM
caggi is offline
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Default thanks for the replies

I'll try cleaning the sensor, how do I know if it's the sensor or the cat? Or the intake gasket? I haven't done anything yet, just some banging on the muffler and it's loose inside. The cat might be too haven't hammered on that yet.
(I try to get more THC in, maybe I'll forget about that durned light! )
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