The story & concerns regarding catalytic issue

Check engine light was on.. code determined to be: PO420, "Catalyst system efficiency below threshold Bank 1"




Took truck into Firestone and after spending $100 for diagnostics which they said would be more in depth than my code checker they gave me an invoice for $2,500 saying a needed both 2 new sensors and 2 new catalytic converters.

I'd like some advice on how to proceed?
Should I purchase all the parts as they say and where? Are the part numbers on this invoice accurate?
Are they just overcharging me and could it be as simple as changing one sensor??

I've cleared the code and it stays off for a couple days but then comes right back on again so I know its not just a fluke.

Here is a copy of the invoice they gave me.



I'd like some advice on how to proceed?
Should I purchase all the parts as they say and where? Are the part numbers on this invoice accurate?
Are they just overcharging me and could it be as simple as changing one sensor??
Anyone know a good place to get these parts or do one step better and get parts better than stock?

 

I would switch out the O2 sensors first and clear the code. If the code comes back then I would look towards the cats.

 

I would almost guarantee its just the sensors. Look them up on rock auto they are cheap. replace them and if you throw a code after replacing them then get some O2 simulators and dont worry about it that is way to much money IMO

 

Be sure to buy Denso sensors, thats what came OEM, and what works the best.

 

both sensors right? where can i get denso sensors?

 

went to rockauto and they have a lot available.. should i get both sensors or just upstream or downstream?

 

I would replace both at the same time, but the upstream one for sure.

edit: And check Amazon for denso sensors.

 

thanks, not to seem helpless but im on Amazon.com looking for denso sensors and they have hundreds of them and no good way to input what kind of car you have to help indicate which sensors do you need.

http://www.amazon.com/s/ref=sr_nr_scat_15735801_ln?rh=n%3A15735801%2Ck%3Adenso+sensors&keywords=denso+sensors&ie=UTF8&qid=1337107801&scn=15735801&h=348eda178390937a8703018c3aff62364f8e7fd6#/ref=sr_nr_p_4_0?rh=n%3A15684181%2Cn%3A%2115690151%2Cn%3A15719731%2Cn%3A15729591%2Cn%3A15729601%2Cn%3A15729701%2Cn%3A15735801%2Ck%3Adenso+sensors%2Cp_4%3ADenso&bbn=15735801&keywords=denso+sensors&ie=UTF8&qid=1337107819&rnid=49681011

Heres a link to the listings on amazon... could you recommend the model numbers? I appreciate it.

 

for the upstream i was told to purchase this one

http://www.amazon.com/Toyota-Oxygen..._2?s=automotive&ie=UTF8&qid=1337109253&sr=1-2

 

Use this website to get the right part number for Denso sensors, then you can shop around places like Amazon, or ebay. http://www.urdusa.com/More-Products.../index.html?osCsid=2gp2qhia6etb5ckn8g2rrlq460
EDIT: Im betting you have a Cali vehicle since you have two converters. If you are unsure, look under your hood at the sticker on the underside of the hood. It will say whether its a cali or 49 state vehicle.

 

You should also get the socket head for O2 sensors...it has a whole side cut out of it so the cable harness can stick out and not interfere. I allows the use of a socket wrench or breaker bar to remove instead of a some short open ended wrench that can slip off. Its a cheap tool when I looked one up.

After replacing the sensors and if needed, you can try removing the Cat and dropping it in some heavy detergint cleaner, let to soak and try to clean the honeycomb. Once dry, re-install and see if the code stays away. or look into those O2 simulators

Stupid emissions crap is all a racket...

 

I second the o2 sensor wrench or "crow's foot" wrench.

As to how to fix it, there are ways that won't pass emissions, do you have emission programs where you live? Or do you want it to be perfect? (if the sensors don't fix the issue)

 

Thanks for all your help. ive added the OEM denso upstream 02 sensor and reset the code and hours later the same code came back on.. could this just be a fluke or is there something else wrong, could the sensor be bad?? original code was: "PO420, "Catalyst system efficiency below threshold Bank 1"

what else code be wrong?

 

The up-stream sensor is for air-fuel mixture, the downstream sensors are for making sure the cat is working properly. 2 completely different sensors. If you get the wrong sensors you may get the P0125, P0133, P0130 codes < this is happening to me.

 

hello thanks for your effort but i was not referring to the downstream sensor. i am getting a p420 bank 1 error and was told just to replace the upstream, sensor. i am not getting any of the codes you mentioned but thanks for your response anyway.

hopefully someone else can help get to the bottom of this.

 

Ment to say sensors. But good luck.

 

$57 for the rear sensor (Denso oem) with free shipping.

Link

 

The 3.4l engine is very well known for the p0420 cat code. Not much way around it but then to replace the cats. Its not the sensors and they wont fix the problem so i wouldnt waste your money. The price quote you got sounds about right. They are just expensive parts.

 

I have seen p0420 fixed by replacing the rear sensor with an oem denso unit. If it gets clogged or wears out, it will cause the code. The catalytic was soaked in laundry detergent overnight though.