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Toyota Repair/P0420 error code


Just A Fan wrote at 2007-05-17 17:19:57
I would recommend taking some where to have a diagnostic test ran on it.  That way you can find out how many codes are stored in the computer.  Also you want to find out what caused your cat to go bad in the first place.  It does not make sense to replace it and not fix the problem that is causing it.  I had the P0420 code that was detected by auto zone but I also had another code that did not show up from the auto zone read.  To make a long story short I took it to a shop and they cleaned the Mass Air Flow sensor and that eliminated both codes.  

Gio17vani wrote at 2007-09-23 13:34:15
P0420 isn't always the cat converter.  It can be triggered by bad 02 sensors both upstream or downstream of the cat since those are what your computer uses to determine the cat is working or not.  Also if the vehicle has an egr valve that needs to be cleaned can sometimes trip the p0420 code.  Cleaning egr valve is easy to do and costs maybe $10 and a couple 02 sensors run about $200 from a store but can be found online or ebay for $100 for the pair sometimes even less $50-75

Kent wrote at 2012-12-02 03:43:34
I have ran into this code several times in my local club. More time then not just replacing the gas cap fixes this code. Its a cheep fix over replacing the cat or 02 sensors.

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