My remedy for P0420

[Craig A Updegrove]

I was have a P0420 on my Acura Integra after replacing it with a magnflow Cat. I did some research on the internet. I found an fix. It is taking 2 sparkplug non foulers drilling one out inserting the O2 sensor in the drilled out one and inserting the untouched one in the CAT so that it is one unit. They also so sell the unit on ebay, angled ones for tight spaces. It has been 3000 miles since I put mine on and I haven’t had a single CEL P0420. My car also passed inspection with it installed. I am not saying it will work for everybody, it did worked for me. Check your states reqirements for inspection so that you are not breaking any laws

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[college man]

Thanks for the tip. 🙂

[EricTheCarGuy]

Aftermarket cats don’t often work out but I suppose you have found a work around.

[Craig A Updegrove]

5 months and still no CEL P0420

[Its me]

This is the fix for the P0420 problem on many Toyotas. And yes, aftermarket cats can throw the P0420 code right after installation. Even though the exhaust system will pass a sniffer test… Toyota made this code so sensitive that ECMs had to be reflashed so “still good” Cats would be able to pass vehicle inspections.

A P0420 code says that a vehicle fails emissions. Plain and simple, in a State that only does ODB II testing you can be screwed.. Some States, including California had to have an alternative testing program developed so people could prove their vehicles were still within emissions requirements even though their CELs were on with P0420….

The problem is that the government now requires vehicles to “tell on themselves”…
Toyota made their vehicles (ECMS) way too honest… and when a cat might be still at 90% efficiency, it would throw the code, thus FAILING EMISSIONS and essentially requiring a new CAT when one was not really necessary. Toyota and the Government did fix this by requiring Catalytic Converters to last a certain time… Saving Thousands for customers but it was a stop gap IMHO..

One of those extensions they sell on ebay will fix the problem. It is a unscrew, and screw on fix for the trouble light.

I am hesitant to endorse this as an on road fix because it is considered tampering with emissions control system… Will anyone get caught… highly unlikely when the car is registered in a state that does not require emissions inspections……. However, personnel in states that do emissions inspections are trained to look for them….

Just my 2 cents…

[Konrad]

Search eBay for ‘oxygen sensor spacer’. You don’t need to drill anything. This is a common solution for cat efficiency faults. Modern engines can throw a cat fault if the efficiency drops just 5%. Often you can still pass the gas analyzer test.

For older cars, you can also get an oxygen sensor simulator. It is a signal generator that is installed in place of the post cat sensor. This is useful if you have removed your cat entirely. Some states only perform an OBD test so you can be spewing raw fuel out the exhaust and still pass. Not that you would do such a thing because you are a respectable member of the public and respect the regulations put in place by the EPA.

[Author]

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