P0420

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treesleavedents
Posts: 200
Joined: Thu Apr 16, 2015 12:50 pm
Location: phoenix

P0420

Post by treesleavedents »

I freaking hate this code and everything about it. That is all.

replaced both 02 sensors and the cat (finally installed my PPE header and midpipe with a high flow cat, and the damn code is still there!
2003 Vibe GT. PPE exhaust. Injen CAI. Mfactory LSD. Eibach springs. Corbeau GTS2 seats. Custom stereo, lighting, sound deadening, and upholstery. http://forums.genvibe.com/phpBB3/viewto ... 30&t=44330
zbyers
Posts: 1767
Joined: Thu Apr 03, 2014 6:12 pm
Location: Sheffield, Pennsylvania

Re: P0420

Post by zbyers »

99% of the time, this code is for the cat. Replacing your o2 sensors will almost always be a fruitless effrot.

As other suggested on the FB page, just pick up some o2 sensor spacers/defoulers and call it a day.
'74 Thing, '79 El Camino, '83 VW DoKa '91 Vanagon, '03 Base, 04 GT
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treesleavedents
Posts: 200
Joined: Thu Apr 16, 2015 12:50 pm
Location: phoenix

Re: P0420

Post by treesleavedents »

that's my next step, I guess a high flow cat isn't enough to solve it...
2003 Vibe GT. PPE exhaust. Injen CAI. Mfactory LSD. Eibach springs. Corbeau GTS2 seats. Custom stereo, lighting, sound deadening, and upholstery. http://forums.genvibe.com/phpBB3/viewto ... 30&t=44330
treesleavedents
Posts: 200
Joined: Thu Apr 16, 2015 12:50 pm
Location: phoenix

Re: P0420

Post by treesleavedents »

Bought and installed an O2 spacer. Now I'm getting a P0136 code. I'm off banging my head against a wall over here lol.
2003 Vibe GT. PPE exhaust. Injen CAI. Mfactory LSD. Eibach springs. Corbeau GTS2 seats. Custom stereo, lighting, sound deadening, and upholstery. http://forums.genvibe.com/phpBB3/viewto ... 30&t=44330
jolt
Posts: 945
Joined: Sun Mar 02, 2014 2:07 am
Location: Twin Cities, Minnesota

Re: P0420

Post by jolt »

Here are some links I found about the P0420 code on Toyota:

https://www.autoserviceprofessional.com ... DTC?Page=1

https://priuschat.com/threads/need-help ... ts.207453/

http://www.fixya.com/cars/t1056719-p042 ... ta_corolla

https://www.discountconverter.com/catal ... -&News=326

https://www.corolland.com/forums/index. ... ode-p0420/

These may give you some other ideas of what to check. The link about the TechStream software showing the voltage values should give you something to check and may be why you are now getting the P0136 code after your extender was added. After looking through the above links the problem could be something on the intake side that could effect the exhaust. Any air leaks in the exhaust or intake, the MAF sensor, the idle speed controller, the flex gasket, non-OEM oxygen sensors, and non-OEM convertor can all cause the code. Things that stand out are the oxygen sensor voltage changes and the fuel trim readings. If you do not have the proper tools to check these things then all you can do is guess and that can get expensive. Toyota does this code different then other manufactures so watch what information you read as other manufactures will not deal with this code the same as Toyota. TechStream is Toyota factory software developed by Denso for diagnosing the on-board computers through the OBII port.
treesleavedents
Posts: 200
Joined: Thu Apr 16, 2015 12:50 pm
Location: phoenix

Re: P0420

Post by treesleavedents »

Thanks! I haven't had a chance to dig through those links yet but thanks for sharing em! I'm also getting a P0125 code as well now so I'm pretty sure the defouler messed something up. need to lift it up and check the wires for breaks first though...
2003 Vibe GT. PPE exhaust. Injen CAI. Mfactory LSD. Eibach springs. Corbeau GTS2 seats. Custom stereo, lighting, sound deadening, and upholstery. http://forums.genvibe.com/phpBB3/viewto ... 30&t=44330
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