2004 Volkswagen Passat "code p0421 trouble" Questions

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Question about Volkswagen Passat

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...p0421 do I have to change sensors or use spark plug trick? Guide me please. there is a code table here:code table Hi guy,this is a Diagnostic Trouble Code Table ,it can help you.And you need a cheap ...

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Question about Volkswagen Passat

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trouble code p0421 could this be a sensor A bad cat, exhaust leak, loose sensor, bad engine controller are the potential causes. Good luck.

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...P0421, P0431 consistently and P0456 rarely. Can one determine if the cc's are working by the exhaust smell? I have had the threshold codes since I b 120K miles No major accident damage Everything ...

Question about Volkswagen Passat

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...Code: P0421 Catalyst Efficiency Below Normal (Bank 1) Possible Causes: Air leaks at the exhaust manifold or in the exhaust pipes Catalytic converter is contaminated, damaged or has failed Front HO2S ...

...P0421 on 2006 Mitsubishi lancer. How to fix Code PO303 is listed as a number three spark plug misfire and PO421 lists as a catalytic converter problem. The trouble with codes is it isn't often the ...

P0421 : Warm Up Catalyst Efficiency Below Threshold 2001 v6 galant this code marks a bad cat. The ecu can get this wrong. it means the rear 02 is reading oddly, Aka. the cat monitor (OBD2) it can be a

Question about Volkswagen Passat

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...code p0421 and p0421 pd OBDII scanned describing something like warm up catalyst threshold bank....Please help I believe this has to do with your catalytic converter. Sounds like it might be getting ...

Question about Volkswagen Passat

1 Answer

1998 mazda protege p0304 and p0421 codes P0304 Code Cylinder 4 Misfire P0421 OBD II Trouble Code

Question about Volkswagen Passat

1 Answer

...code P0421 may mean that one or more of the following has happened: The catalytic converter is no longer functioning properly An oxygen sensor is not reading (functioning) properly A sparkplug is ...

...code P0421 on a 2000 Miata what can I do to fix this issue I get a OBD11 code of P0421. I have removed and replaced spark plugs and the vehicle is running great. I still get the check engine light ...

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