Another P0420 thread

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CheeseSteaks

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recently purchased 04 4runner with 130,000 miles. It sounded like it had a slight exhaust leak but passed NJ State Emissions test last week so i wasn't worried about the small exhaust leak.

Yesterday I took it on the beach for the first time. On the way off the beach, the Check Engine light and both of the VSA lights came on and stayed on.

Do you think the code was a result of the exhaust leak? The added stress of driving on the sand?

Where should I start to trouble shoot the problem? And when should I take it to a shop? What a new cat cost?

Thanks in advance for the advice.
 
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CheeseSteaks said:
recently purchased 04 4runner with 130,000 miles. It sounded like it had a slight exhaust leak but passed NJ State Emissions test last week so i wasn't worried about the small exhaust leak.

Yesterday I took it on the beach for the first time. On the way off the beach, the Check Engine light and both of the VSA lights came on and stayed on.

Do you think the code was a result of the exhaust leak? The added stress of driving on the sand?

Where should I start to trouble shoot the problem? And when should I take it to a shop? What a new cat cost?

Thanks in advance for the advice.
Click to expand...

It could be the leak, or a bad CAT. If you hear a small leak, I would definitely resolve that first as it may solve the whole issue very cheaply. Basically if there is a leak near the engine, the extra oxygen enters and throws off what the sensors are seeing, so that can throw that code. Another common problem is the manifolds are prone to cracking which can cause leaks. You didn’t say if yo have a v8, or 6...
 
Terminator03 said:
It could be the leak, or a bad CAT. If you hear a small leak, I would definitely resolve that first as it may solve the whole issue very cheaply. Basically if there is a leak near the engine, the extra oxygen enters and throws off what the sensors are seeing, so that can throw that code. Another common problem is the manifolds are prone to cracking which can cause leaks. You didn’t say if yo have a v8, or 6...
Click to expand...


Probably should have included that... Its a V6
 
I'd look to cleaning the injectors and checking the coils. Have the spark plugs been replaced? Rislone Gasoline Fuel System Treatment has restored power in my cars in that they downshift less when going uphill on cruise control. It's said to have PEA according to Q and A on https://www.amazon.com/Rislone-Gas-Fuel-System-16-9/dp/B008FRISTA also some Gumout products https://gumout.com/fuel-additives/ have PEA too, which I read PEA is very desirable for cleaning injectors. What I'm suggesting is a misfire can also cause the code according to https://repairpal.com/OBD-II-Code-P0420 the misfire being what you may hear as an exhaust leak, also at Repair Pal
Most Toyota vehicles need an OEM Catalyst, especially if there is a Catalyst-related software update required. Toyota vehicles usually re-set the P0420 code unless an OEM catalyst is used as a replacement. It is common for mechanics to replace all the Oxygen sensors only to find that the Toyota vehicle required an OEM Catalyst.
Click to expand...

I'm also going to guess Brake light switch for VSA lights. It's the one above the brake pedal, easy to change or just first double check to see that it's hooked up and operating correctly. My apology if this is all simple stuff you've already addressed, I'm getting tired. Any other code trigger when the VSA lights came on?
 
Im assuming that the VSA lights came on with the check engine light as some kinda precautionary measure.

I haven't changed the plugs yet as I just got the truck... Ill change them tomorrow if the weather cooperates... also Ill try the fuel system treatment. I also noticed that the dash is telling me I'm getting between 20-21 miles a gallon... I thought that seemed kinda high. Not sure though.



Supersonic said:
I'd look to cleaning the injectors and checking the coils. Have the spark plugs been replaced? Rislone Gasoline Fuel System Treatment has restored power in my cars in that they downshift less when going uphill on cruise control. It's said to have PEA according to Q and A on https://www.amazon.com/Rislone-Gas-Fuel-System-16-9/dp/B008FRISTA also some Gumout products https://gumout.com/fuel-additives/ have PEA too, which I read PEA is very desirable for cleaning injectors. What I'm suggesting is a misfire can also cause the code according to https://repairpal.com/OBD-II-Code-P0420 the misfire being what you may hear as an exhaust leak, also at Repair Pal

I'm also going to guess Brake light switch for VSA lights. It's the one above the brake pedal, easy to change or just first double check to see that it's hooked up and operating correctly. My apology if this is all simple stuff you've already addressed, I'm getting tired. Any other code trigger when the VSA lights came on?
Click to expand...
 
Those VSC lights come on anytime you get a check engine light.

I would address the exhaust leak first , that will definately cause a P0420 code.

In all cases I’ve read where the brake light switch was failing, you see the VSC lights with ABS light and no Check engine light.
 
I got a similar code recently. Tried o2 sensor, light is still on. I dont have emissions in my state, should i still replace the catalytic converter? My gas mileage was ok but it recently dropped from 17.8 to 16.4 mpg, but that might be from me eating in my car with the engine on. Im calculating it by hand, lol.


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UPDATE: They are replacing the cracked manifold, cat, and sensors on one side... Should be done tomorrow morning. Gonna cost $1100. I hope I'm in the clear after that.
 
I just got a voicemail from the service writer... He said the traction control lights are still on and that a toyota dealer has to recalibrate the system to get it back to "point zero." He mentioned it costs about $90. Can anyone elaborate on this?
 
From my experience P0420 codes are always so vague. My other vehicle is throwing one and its like a game trying to narrow what the problem might be.
 
2003 4runner had P0420 code bank1 cat efficiency, found a local muffler shop that would weld on a generic cat for $250 on, had the job done, went to pick up the truck, shop guy says the P0430 code came on when he checked the DTCs. He said the cat he just replaced was "clean as a whistle" said it appeared i had a rich/lean problem with the truck. So i said ok let me investigate before i replace the bank2 cat. I replaced the spark plugs, cleaned the MAF, replaced PCV valve, replaced pre cat O2 sensors on both banks, used only 93 octane gas for two fill ups, and the P0430 code would never go away. I used my tool to watch the data stream on the post cat sensors and the bank 1 sensor looked normal, no fluctuations, steady number, then i watched bank 2 post cat sensor, the tell tale signs of a bad cat, number fluctuating rapidly and a large variant, so I thought well i need to replace that cat as well, but....I decided to replace the post cat O2 sensors before I did that, only reason was I had a $100 credit at rockauto and wanted to use it lol, no other reason, so i changed both post cat O2 sensors and VOILA! the P0430 code is off and has been off for 3 days. Usually after I clear the P0430 code, after 1 day it came back on (normal driving). So...maybe I wasted $250 on the bank1 cat replacement? who knows.

But now, the rich/lean situation my muffler shop guy pointed out...I checked the data stream on the short and long term fuel trim, MAF rate, Fuel system etc (after removing negative battery terminal and allowing the fuel trims to erase), the long term fuel trim on bank 2 is 99.2%, i can clear the trims and the 99.2% always returns. Gas mileage is horrible. I can find no obvious leaks in the exhaust or vacuum leaks, maybe I have a bad injector? intake gasket sucking air? some un-metered air entering the system somewhere. Who knows.....this is a cat and mouse game i rather enjoy to be honest lol
 
CheeseSteaks said:
recently purchased 04 4runner with 130,000 miles. It sounded like it had a slight exhaust leak but passed NJ State Emissions test last week so i wasn't worried about the small exhaust leak.

Yesterday I took it on the beach for the first time. On the way off the beach, the Check Engine light and both of the VSA lights came on and stayed on.

Do you think the code was a result of the exhaust leak? The added stress of driving on the sand?

Where should I start to trouble shoot the problem? And when should I take it to a shop? What a new cat cost?

Thanks in advance for the advice.
Click to expand...

Fix the exhaust leaks, clear the codes and drive it. Cat codes will set if there is an exhaust leak upstream of the cat. No, the sand had nothing to do with it.
 
CheeseSteaks said:
I just got a voicemail from the service writer... He said the traction control lights are still on and that a toyota dealer has to recalibrate the system to get it back to "point zero." He mentioned it costs about $90. Can anyone elaborate on this?
Click to expand...


A zero point calibration is easy to do, there are many videos on you tube to show you how. Toyota has a tool to reset it (part number SST 09843–18040). It consists of 2 wires and a switch, I built the same thing with spare parts and doing the calibration takes 5 minutes. I think $90 is excessive.

I don't understand why Toyota engineers released a product in which such an important item as traction control would be disabled by a simple trouble code.
 
Everything is good thus far. I was even able to do the point zero calibration myself!

Now I just gotta figure out why my tach stopped working for 20 mins today!
 
CheeseSteaks said:
Everything is good thus far. I was even able to do the point zero calibration myself!

Now I just gotta figure out why my tach stopped working for 20 mins today!
Click to expand...

I have pretty much the same issue you had: exhaust leak and P0420 code. Did the code ever come back after you replaced your headers/cats?
 
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