PO420 code help, need cats to pass inspection.

[jmferg]

I failed inspection for a pending (not active) code.
I need to get it back on the rode for work. O2 sensors tested in the correct resistance range. I have one, maybe both bad cats.
Dealer quoted me $3,500.
If I only need to replace one I would like to take that route. The o2 sensor that reads is behind both so I cant narrow it down to which is bad. Would a temp gun after a long drive be a god determination of which is bad?

I will be fixing this myself and need to know which if aftermarket cats will work or if these are like other Toyota parts where only oem will work.
If aftermarket is ok, I plan on using magnaflow direct fit parts.
Has anyone used these and knows the difference between the different Downpipes and mid pipes?

Sent from my iPhone using Tapatalk

 

[jgue467]

Have you tested the rear 02 sensor? Many on here find a p0420 is taken care of by replacing the rear sensor. It's certainly less expensive than a cat. Don't know about eom vs. non on cats but I suppose non-oem is just fine (never read otherwise). Luck. :cowboy:

 

[fourfive]

The rear 02 sensor took care of my p0420 code. I didn't have time to test the sensor but replaced it because it was the original and it fixed the code.

The 2 experiences I had with an aftermarket cat (honda & acura) weren't good. They did fine for a couple years then went bad. Found out later on that the OEM cats were probably fine and the issue was misdiagnosed.

 

[the walrus]

P0420 can be triggered when the cat is at as high as 95% efficiency. Meaning, the cat is still working at 95%, but since it has lost 5% efficiency, it throws the code. Bottom line, in a case like that, the vehicle is still burning clean, environment/rain forest/polar ice caps are still ok, blah, blah, blah.

To correct the code, I have had success using this device on 3 different vehicles. It simply spaces the O2 sensor back a short distance, making the computer think the vehicle is above the 95% threshold, and therefore no code is thrown.

Again, in a case like that, the vehicle is still burning clean, cats are still doing their job. $12 instead of several hundred or several thousand.

 

[TheDurk]

P0420 can be triggered when the cat is at as high as 95% efficiency. Meaning, the cat is still working at 95%, but since it has lost 5% efficiency, it throws the code. Bottom line, in a case like that, the vehicle is still burning clean, environment/rain forest/polar ice caps are still ok, blah, blah, blah.

To correct the code, I have had success using this device on 3 different vehicles. It simply spaces the O2 sensor back a short distance, making the computer think the vehicle is above the 95% threshold, and therefore no code is thrown.

Again, in a case like that, the vehicle is still burning clean, cats are still doing their job. $12 instead of several hundred or several thousand.

You should mention this won't work on 3G 4runners between '96 and 2000 that use the flange-type rear sensors, only on '01 and '02 that use the screw-in.

The URD Simulator works on all years.

http://urdusa.com/store/Electronics-Rear-Sensor-Simulator/c66_170/p1230100014/URD-Rear-O2-Simulator,-5VZ-FE-3.4L-V6/product_info.html

I would only go that route after I had ruled out any exhaust leaks. Original gaskets on our trucks are on the verge of turning to dust, so this is a frequent issue. Then swap the rear sensor if it has 80k or more. So far, this is all I have needed to keep my factory cats alive and my CEL off..

 

[jmferg]

No exhaust leaks. Dealer supposedly smoked system and checked that.
Rear o2 tested within the correct range of resistance.
Pretty strict here. Most testing facilities have posted notices stating any emissions altering equipment is vehicle impoundment and a several thousand dollar fine. It has already failed at the dealer and they have looked it over so I won't get away with any cheats.
O2 simulators and spacers are directly listed as banned devices as well as searched for items on the inspection checklist.
I have to fix this correctly


Sent from my iPhone using Tapatalk

 

[jgue467]

Just curious what hard ass state you're in, so I can avoid it! :cowboy:

 

[jmferg]

NY
NY and Cal are the worst from what I've read


Sent from my iPhone using Tapatalk

 

[Magmotor]

No exhaust leaks. Dealer supposedly smoked system and checked that.
Rear o2 tested within the correct range of resistance.
Pretty strict here. Most testing facilities have posted notices stating any emissions altering equipment is vehicle impoundment and a several thousand dollar fine. It has already failed at the dealer and they have looked it over so I won't get away with any cheats.
O2 simulators and spacers are directly listed as banned devices as well as searched for items on the inspection checklist.
I have to fix this correctly


Sent from my iPhone using Tapatalk

what year is your 4R?? If you have a 2000 and below, these Cats will work. If you have 01-02 you have an 18mm threaded type sensor. You can get an earlier (flange type) but don't know if the j-connectors are the same.:shrug: Magnaflow only sells 'flanged type Cats'.... just thought you should be aware of this.....

 

[jgue467]

NY
NY and Cal are the worst from what I've read


Sent from my iPhone using Tapatalk

Bummer, knew about cali but not NY. Texas i guess is easier in that it has 2 types of inspections. One for the 'cleaner' counties that doesn't smog test your vehicle, just safety stuff. And the other (bigger cities) that does smog test But Texas still allows one of the various emissions items to be in a 'not ready' state and still pass! :cowboy:

 

[jmferg]

Bummer, knew about cali but not NY. Texas i guess is easier in that it has 2 types of inspections. One for the 'cleaner' counties that doesn't smog test your vehicle, just safety stuff. And the other (bigger cities) that does smog test But Texas still allows one of the various emissions items to be in a 'not ready' state and still pass! :cowboy:

You're lucky

what year is your 4R?? If you have a 2000 and below, these Cats will work. If you have 01-02 you have an 18mm threaded type sensor. You can get an earlier (flange type) but don't know if the j-connectors are the same.:shrug: Magnaflow only sells 'flanged type Cats'.... just thought you should be aware of this.....

Thank you for noticing that, I didn't catch it




Sent from my iPhone using Tapatalk

 

[jmferg]

I called walker customer service and despite was summit racing says, walker has both kits in the correct fitment for my 2001.
I have a brand new denso unit I will install and check to see if that does the trick even though the resistance on the current one read ok


Sent from my iPhone using Tapatalk

 

[TheDurk]

No exhaust leaks. Dealer supposedly smoked system and checked that.
Rear o2 tested within the correct range of resistance.
Pretty strict here. Most testing facilities have posted notices stating any emissions altering equipment is vehicle impoundment and a several thousand dollar fine. It has already failed at the dealer and they have looked it over so I won't get away with any cheats.
O2 simulators and spacers are directly listed as banned devices as well as searched for items on the inspection checklist.
I have to fix this correctly


Sent from my iPhone using Tapatalk

Resistance test is pretty meaningless for a P0420. It only confirms the heater is working, but the key here is response speed, and the ohm check tells you norhing about that.

 

[4runnerWiniarski23]

Just to comment about strictness of NY, What part of NY are you in?

I also have P0420 code that i have fighting, I also have an exhaust leak so I believe this to be the main culprit. In your case if the new sensor doesnt work I would just swap in the rear simulator and take it to a big name chain store. 9 times out of 10 they wont go under the car to verify the 02 sensors are not altered with. If they do you can always say its an non-oem sensor you got online. (just play stupid) They arent looking to nail you for non-compliant emission equipment.
Again this is my own 2cents take it for what its worth...

 

[jmferg]

Resistance test is pretty meaningless for a P0420. It only confirms the heater is working, but the key here is response speed, and the ohm check tells you norhing about that.

I did two checks per the Haynes manual
To my understanding, one was for functionality and the other was to test the heater

Just to comment about strictness of NY, What part of NY are you in?



I also have P0420 code that i have fighting, I also have an exhaust leak so I believe this to be the main culprit. In your case if the new sensor doesnt work I would just swap in the rear simulator and take it to a big name chain store. 9 times out of 10 they wont go under the car to verify the 02 sensors are not altered with. If they do you can always say its an non-oem sensor you got online. (just play stupid) They arent looking to nail you for non-compliant emission equipment.

Again this is my own 2cents take it for what its worth...

Downtown Albany.
Since it's the first time it's been registered here I could say that's how I bought it lol.


Sent from my iPhone using Tapatalk

 

[GrassFed]

With any amount of mud and careful installation the simulator by URD might do the trick.

Did you check for certain that the flange just behind the rear O2 is not leaking at all? As the exhaust gas pulses out of the system it can momentarily suck in some outside air and even the smallest amount can trigger an inefficiency code due to the 95%+ efficiency it needs to be at in order to not trigger a code.

You can check the inlet and outlet temperatures to see if the CC (Catalytic Converter) is doing it's job. A clogged CC will not only be hotter at the beginning, but will almost always manifest itself in positive fuel trim numbers as well. This is being from what I have researched at least, as I have the same P0420. I believe mine is an exhaust leak though as my CC is hotter at the outlet and the flange just behind the O2 is deteriorating. Wishful thinking I guess.

As a side not it is pretty crazy to think of the efficiency our cars need to perform at in order not to throw a code. It sure makes me think twice about nit-picking performance because with only a 5% buffer for the CC and less for the misfire monitors it looks like the computer does a fine job of nit-picking without any help from me.

This is of course my non-professional take on the situation. Remember how much you paid for this advice.

Good luck and please post back on what solved your problem.

Matt

 

[4runnerfevr]

If you want a quick remedy, you can clear the code by disconnect the battery and drive the truck for about 70 miles to pass the smog test.

 

[jmferg]

With any amount of mud and careful installation the simulator by URD might do the trick.



Did you check for certain that the flange just behind the rear O2 is not leaking at all? As the exhaust gas pulses out of the system it can momentarily suck in some outside air and even the smallest amount can trigger an inefficiency code due to the 95%+ efficiency it needs to be at in order to not trigger a code.



You can check the inlet and outlet temperatures to see if the CC (Catalytic Converter) is doing it's job. A clogged CC will not only be hotter at the beginning, but will almost always manifest itself in positive fuel trim numbers as well. This is being from what I have researched at least, as I have the same P0420. I believe mine is an exhaust leak though as my CC is hotter at the outlet and the flange just behind the O2 is deteriorating. Wishful thinking I guess.



As a side not it is pretty crazy to think of the efficiency our cars need to perform at in order not to throw a code. It sure makes me think twice about nit-picking performance because with only a 5% buffer for the CC and less for the misfire monitors it looks like the computer does a fine job of nit-picking without any help from me.



This is of course my non-professional take on the situation. Remember how much you paid for this advice.



Good luck and please post back on what solved your problem.



Matt

I understand your point on how precise some of these states expect a 20yr old vehicle to run. Check engine lights are too subjective to be an indication of how your engine is performing. I bet mine would pass a tailpipe probe, actually I know it would because it did in another state

If you want a quick remedy, you can clear the code by disconnect the battery and drive the truck for about 70 miles to pass the smog test.

This won't work because they plug into the obd II port and the map will read that is hasn't set yet- grants you an automatic fail.



Sent from my iPhone using Tapatalk

 

[GrassFed]

I apologize for the misunderstanding. I wasn't trying to touch on states' strict emissions laws. I was in a way admiring how precise some of our systems are as far as trouble codes.

The objectivity of these systems is pretty neat because ultimately it makes them easier to diagnose. Being that they are number and algorithm based versus being all seat of the pants.