Drive cycle to clear P0420 code for smog test

First off with the Prius they're generally will be none of that You can drive until your tires fall off if your catalytic converter can absorb the flood test gas or whatever it shoots in there when it does that light's going to be lit forever You can try a spacer if you don't know what that is don't worry about it your smog is coming up and you're probably not going to pass whether you can get refereed or something goes on there in California have no idea the government there thinks everybody's well to do so you're expected to just purchase up a new car when the time comes or you can spend about 16 $1,700 on a cat from Toyota and pray. the new converter from Toyota doesn't put the light out you're out that money Toyota's not taking it back so you might want to make arrangements to do something else since you're stuck in a state where there's not much recourse for regular people and not regular people wouldn't care about a '07 Prius or whatever it is.

 

Borrow an obdii reader from autozone and turn it off

 

That doesn't do anything It comes right back on very quickly like before you can get over to the test and then I think the equipment that's used for inspection purposes tells the technician or maybe even our own OBD2 readers that are good enough can tell when the last time the codes were cleared and they require X amount of miles or some kind of nonsense like that. The car runs a special test on the catalytic converter whenever it's prescribed and once it can't pass that test that's that like I said before you can try a spacer if that works then so be it if they lift the car up and go to looking I think they can fail you for the spacer I do believe but I'm not positive of that It's been many years since I've had to deal with full-on emissions testing and when I did it was in Western Massachusetts.

 

The nonsense you're looking for in 'monitor status' or 'readiness'.

The car has different self tests ("monitors") that are there to check and set different trouble codes. Because the different monitors check different things, they have different conditions for when they can run. Some of them can run right away when you turn the car on, some can only run while driving in certain conditions, the one for evap runs about 5 hours after you turn the car off.

Whenever you clear any codes, all of the monitors go back to "incomplete". They'll eventually all show "complete" again, one by one as they each get the needed chance to run. If any are still "incomplete" at your inspection, they generally send you away to come back when they're complete.

That's why it's not so easy to just clear a code like P0420 and go get inspected. If you go in too soon for the test to run again, it shows incomplete and they send you away. Of course once the test runs, it notices the cat is still bad and sets the code.

 

It has been 2 YEARS=Never had PO420 on the Prius again
See video of what I did.

prius p0420 fix - Bing video

 

I learned the cat monitor needs a highway run at 60-65 mph for a few miles, by having an older vehicle. It has to get hot enough. I take my obd reader with me to know when. Only need a cheap one. It will say test available, then it has to say ready. Don’t have to have one, it will reset. Go 10-20 miles to make sure.

 

Is this the spacer deal I can't see the video.

 

Or there is a resistor or some kind of fix like that too We did this back in the '80s on some of the early O2 sensor cars

 

It has been 2 YEARS=Never had PO420 on the Prius again
See video bellow of what I did.

 

Yes the spacer we'll see if it works shortly

 

NOTE= It has to be the same spacer that is on the video [ with the angle on it] -other spacer do not work.

 

The spacer doesn't fix the problem. It merely masks it. You won't get the code but you still have the problem.

 

Yeah well the problem is a bad converter or wore out converter or converter that can't pass the prius test that it runs The spacer I have is actually nicer than the one used in this video The one I have has a piece of catalyst material in the elbow portion of the spacer and it's also made out of stainless steel and it swivels You can run it up onto the pipe bung put it where you want it run the stainless steel lock nut up against the pipe and it will lock and stay where you put it and then you can screw in your O2 sensor and then if you don't like the angle it's sitting at or whatever you can loosen the lock nut and move it up down what have you lock it down plug it in good to go I just haven't put it on the '09 car that's had this check engine light on for the PO420 for like 4 years now That's the only code that's ever there so we've just left it alone gets the same gas mileage all the time so on and so forth here where we live we don't have emissions testing so it's not a worry it would be nice to have the light off so it's just not there but it really hasn't mattered so the fitting just sits here on the shop desk staring at me

 

it does depending on the condition of your converter. P0420 or P0430 is just a trigger when a certain % is not meet by the software although the cat is operational it's just that it's not 100% (or whatever the min threshold is) efficient. 80% efficient doesn't mean your cat is clogged or needs to be replaced right away. Sometimes it's not even the cat that's the cause of P0420/P0430. You'll know your cat is bad when you can't accelerate anymore or the engine just don't have power. It means it already broken into pieces and clogging the exhaust providing no back pressure.
Spacers on Volvo (and some other cars that have strict emission software) don't work when the rear O2 sensors are monitored too, when the software detects that the rear O2 is not changing when it tries to change the params it will throw a check engine light (not P0420/P0430) Majority of domestic, Japanese imports and Mercedes can be fixed with spacers since they don't check the rear O2 for discrepancy.

 

A clogged cat will make your engine run badly, which makes a good reason to replace it.

But being unclogged is not the cat's only job. It's actually there to do something, and the monitor test for P0420 is to make sure it still does.

 

No it does not. Whatever was being detected by the sensor is no longer being detected. It hasn't been fixed.

Or you just replace the most likely worn out O2 sensor lol

 

Do you see the irony in this post? LOL

 

No sir All this is already been dealt with It is a bad catalytic converter that can't pass the flood test or whatever the test is called that the car runs on the converter and the computer gets reported back to that the catalytic converter is saturated or oversaturated and is out of spec and you get the PO420 code All of my sensors are denso new on most of the cars on a few not this is only one car that has this problem The other four here don't have a light on on the dash they have had before but that's not this conversation The other four cars have not had the PO420 code as of yet and they range from $274,000 mi down to 172,000. I would love to be able to just replace the O2 sensor or sensors and have the light go off and be done with it but that's not how this works generally speaking at this point in the game. And the irony of the story I'm not sure what that's about but turning the light off doesn't do anything It turns the light off for a few seconds and it comes right back on The longest I've seen it stay off maybe is a few hours and then it's right back on so you will not be able to get to the test before the light comes back on or they say that Im monitors are responding And you're allowed to be given the test so there's that.

 

It will not fix your problem in California or any CARB compliant states, or counties that check for emission. Once they see the spacer, it will automatically fail smog inspection. P0420/P0430 doesn't mean your converter is bad (and needs replacement), it's an efficiency check and the spacer basically skews the reading to make it not read properly. A 0% efficient and a 99% efficient converter doesn't mean a thing to counties who don't do smog inspection. As long as your converter is not clogged (or into pieces) the car will still run at 0% efficient. These spacers are illegal to sell right now, before you could buy it in amazon and eBay but now only a handful of sites sell it.

if you get a code then likely the sensor is working, it's stupid to say to replace the sensor. Majority of the failed sensors are heater circuit problems where you have no other choice but to replace it.