OBD2 code P0420
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OBD2 code P0420
Am having this code P0420 come up every few days and resetting it with a cheap OBD2 reader. It says cat is no good on bank 1. I have run cat cleaner through it but no joy.
I understand this code causes some headaches for other Audi owners. I have a 2005/6 A6 V8 running well other than this. Could it be the Lambda sensor is it worth changing this?
Just looking for some advice before changing the cat which is very expensive. Just annoying having the emission light coming on every few days.
I understand this code causes some headaches for other Audi owners. I have a 2005/6 A6 V8 running well other than this. Could it be the Lambda sensor is it worth changing this?
Just looking for some advice before changing the cat which is very expensive. Just annoying having the emission light coming on every few days.
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Joined: Feb 2019
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if you have access to a bore scope, remove the rear O2 sensor and insert the bore scope, looking inside the cat. If you see a melted blob of cat material then you need a new cat. Labor is very expensive as this takes a large amount of labor hours.
if you need to pass emissions or just want the light off, I am not recommending it, but have heard of it being done, people will sometimes take a 2 pack of spark plug extenders from the local autoparts store, and drill them to a larger hole size to space the O2 sensor and get rid of the check engine light. Keep in mind though that this is illegal as it is tampering with the emissions system.
if you need to pass emissions or just want the light off, I am not recommending it, but have heard of it being done, people will sometimes take a 2 pack of spark plug extenders from the local autoparts store, and drill them to a larger hole size to space the O2 sensor and get rid of the check engine light. Keep in mind though that this is illegal as it is tampering with the emissions system.
Last edited by Chachboi; Jan 31, 2020 at 07:41 AM.
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