P0420 O2 Sensor Simulator

My trucks been throwing a P0420 for awhile now. Thinking it’s probably a cat. Not willing to replace it right now, been looking into an O2 simulator. I’ve seen the URD simulator and I’ve seen the diy version. My truck has a cali exhaust so 2 cats and first sensor is AF and second is O2. Just wondering if anyone has any experience with these or any other tricks to make the cel go away.

 

Simulator will work the best. Unfortunately old Toyotas use a two bolt flanged sensor instead of a screw in so you can't do the spark plug nonfouler trick.

 

You can get a cheap OBD II Code Reader to reset the check engine light.
(Harbor Freight $34)
This is what I do.

But I read the following from a simulator website:
"...if the p0420 or p0430 cel is illuminated the engine control unit (ecu) will put the vehicle into "linp mode" (safe mode) resulting in poor performance and gas mileage"
Is this BS or true?

 

It's BS, it's just a tattletale code. A clogged cat will hurt performance if that's the real issue. But just a bad cat and the code don't affect anything

 

Thanks! I will keep deleting

 

There are screw in to 2 bolt flange adapters. I was sent one with an eBay O2 sensor.

 

It is my understanding that when the MIL/CEL is on the PCM will never enter closed loop status.
I have URD simulators in my Tacoma's in Mexico. The V6 version plugs right into the harness under the passenger seat, neat and clean. The 4 cyl one has to be secured under the truck but both do the job they were designed to do and in my opinion well worth the $ they are asking for the convenience of it.

 

They will enter closed loop as long as the code isn't for an essential fuel management or ignition system. The downstream sensors are not essential at all, simply a tattletale so you won't ignore emissions regulations.

 

I'm in exactly that same situation- I could build a simulator from scratch but it would require cutting wires to hook in. I would much rather have the mating connectors on an end to end extensio = (plug and play) and have all that under the passenger carpet like downtown style, not under the truck in the muck! Sounds like we need the URD simulators but they don't make them anymore? I have a Factory service manual and the wiring diagram, but none of that has the part numbers for the actual connectors we need. Maybe we can use the Wayback machine and see what is there for URD simulator? ewew921@gmail.com

 

Speaking of wayback machine... what was your solution? I'm in a situation with my 99 2.7 right now and it would be much easier to go test pipe but then I need a simulator or something.

 

Toyota Tacoma Oxygen Sensor Spacer Extension, Multi Fit, 90 Degrees, Engine Light Fix - Walmart.com

 

that wont work. I've tried it. Only the URD sim worked, but the EPA banned it. I dont know if the current administration will make it possible to buy them again. Perhaps an email to URD regarding the changes or abolishment of CAFE standards is in order.

 

Yep, tried that already. No interest.

 

that's too bad.

 

URD o2 simulator are worth gold. They sell quick they they pop up too.

 

Yep, I am very glad I got mine in time. I may eventually put a hi flow cat in, just in case mine ever gets clogged up, although to be honest I dont know what the symptoms would even be haha

 

I wish to offer comments that I hope provide clarity and meaningful help:
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P0420 ==> bank 1 catalytic converter system inefficency detected by PCM (paraphrasing). Indeed, that is a "warning" code.
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* You can clear the code from the engine computer with a handheld scanner, but it *will* keep reappearing. Probably every time you drive it if you get up to full operating temp. So that's not a permanent solution. This is just me, perhaps, but I consider repeatedly clearing DTCs to be a poor practice. Either fix the issue or just leave the darn CEL illuminated on your dash.

* As mentioned above, the P0420 DTC does not place the vehicle into "limp" or reduced power mode. That's good. You can keep driving it!

* As mentioned above, the PCM will still go into "closed loop" fuel mgmt strategy with a P0420 DTC. Fuel mgkt strategy in the PCM is controlled by the upstream O2 sensors and the air-fuel ratios (AFRs) they are measuring. This is super important because your fuel mileage will remain the best possible. In "open loop", as such for different DTCs like an upstream O2 sensor failure, the PCM controls fuel from a basic map table and you will tend to run rich and your mileage and performance may noticeably decrease.
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Key point (IMHO): Simulators, O2 sensor defeat widgets, 90 angled extensions, whatever, I consider to be a complete waste of time and money. Please just don't even bother.
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* It is illegal to tamper with emissions control equipment in all 50 states. That's now federal law. I'm not an eco-warrior nor I do I wish to portary myself as a ninny. The likelihood of you getting *caught* tampering with your emissions control system is very low. But don't be ignorant, the consequences are severe. I've always said this. If you wanna catch a charge from your local or state police for something like your window tint being too dark or your muffler being removed, so be it. Pay the fine, whatever. But you do *not* want to FAFO with the EPA (federal agency) on an air pollution violation. They will break you in terms of inconvenience alone and cost to settle.
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My suggestion:

1) If you have two downstream O2 sensors as stated above, simply swap them. Driver side to pax side and vice versa. This is a no cost troubleshooting technique. Perfectly valid. Clear the P0420 DTC and go for a shake down drive.

If the P0420 DTC reappears, then your cat converter should eventually be replaced.

If the P0420 DTC turns into a P0430 DTC, which is a code for Bank 2, then you simply have a bad downstream O2 sensor that can easily be replaced for $50. OEM equivalent part only. Do not order an O2 sensor from Amazon or fleaBay. Get it from an auto parts store or the dealer.

HTH and good luck!

 

Thanks for all the good info. My exhaust is rattling and making other sounds around the cat, and I've looked all over and can't find anything else obvious that is loose, broken, leaking, etc. The cat is actually the only part of the whole exhaust system that is original. It is 26 years old with 182k+ miles, so I wouldn't be surprised if it's broken, partly clogged, or whatever inside. The truck is already plenty slow with a 2.7l, auto, and heavy 265-75r16s, so I can't say whether or not the performance is affected. And the mpg has always been in the mid-teens, but I'm accustomed to that and the performance. It would be nice to get a little more mpg and power. I'd love to find out replacing the cat would help, although I'm not counting on it.

And thanks for your concern re: the EPA. Let's just consider this inquiry an academic discussion, not a legal one.

 

^but of course^

Everything is hypothetical.

My gut instinct is the substrate inside the cat converter, that is the honeycomb like matertial, is finally curmbling apart after all these years. And those piees are rattling around.

 

My OEM cat rattled around badly. Brick inside was indeed broken up. Replaced with a mid priced rock auto unit and aftermarket Bosch o2 sensors before discovering this site. About 5 years in started getting the p0420 code. Pulled cat and cleaned it, bucket and detergent, which did pull a bunch of soot from it. Codes returned. Put spacer on rearward o2 sensor and code returned. Finally just replaced both o2s with new denso. Problem solved.