Error code P0420/30
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Junior Member
Joined: Aug 2022
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Error code P0420/30
Hi everyone,
My 2018 3.5EB has issues with Code P0420/430. The check engine light is on and off. Is it a catalytic converter issue or an O2 sensor problem? I’m thinking about replacing the catalytic converter with an aftermarket product. Do you have any recommendations or experience with this? The truck has 130k miles on it.
My 2018 3.5EB has issues with Code P0420/430. The check engine light is on and off. Is it a catalytic converter issue or an O2 sensor problem? I’m thinking about replacing the catalytic converter with an aftermarket product. Do you have any recommendations or experience with this? The truck has 130k miles on it.
Senior Member
Joined: Mar 2021
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Do you have both 420 and 430 set?
There are Cats for both Banks.
At 130k, very likely not the Ox Sensors.
They are telling you the Cat/s are at low limit / marginal for passing system tests if the CEL does not stay on.
The Ox Sensors report the test results. There is no other way to test and report the results.
Good luck.
There are Cats for both Banks.
At 130k, very likely not the Ox Sensors.
They are telling you the Cat/s are at low limit / marginal for passing system tests if the CEL does not stay on.
The Ox Sensors report the test results. There is no other way to test and report the results.
Good luck.
Last edited by Bluegrass; Jul 7, 2025 at 04:14 PM.
