P0420 , starring a NY 2006 AWD 190k

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Vulcan
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P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

History - 2006 AWD, 190k. The most I've ever fixed on a car is disc brakes, thermostats, oil changes. I am using Torque Lite in my cell phone to read diagnostics.

bought car from a dishonest seller that cleared the engine codes. My mistake, live and learn. I changed the oil straight away, with the correct viscosity of course.

Within 2 days of ownership (and prior to oil change), Bank 1 Sensor 2 activated CEL for low voltage.

Had significant exhaust leak at flange below manifold. Could not repair it myself due to location, rust, and inexperience/lack of tools, had it done by a good mechanic. Satisfied with that.

Low voltage code disappeared. CEL stayed on.

Now I have P0146 (logged, not pending) reading "circuit failure" on that same sensor. The sensor appears to have been replaced unprofessionally. The wires are not wrapped or insulated, plug on the sensor is not wrapped. So any bit of water could get in. I did drive in rain recently.

I also have P0420 (logged and pending), Catalyst out of range.

The engine runs beautifully though. No rattles on startup. Gets 30-35mpg, shifts perfectly. That's why I bought it, even knowing the exhaust had a leak. Does not have a problem at highway speeds.

So, I think first order of business is to get some proper wrap for that o2 sensor wire. The wires look newish, this was a recent cob job.

But, if that does nothing, it seems the next step would be to replace the sensor, is that correct? And if so, where the hell is the plug inside the car? I watched a video showing it on a 2wd Vibe, but pulling up the carpet, things are different. That hole where the sensor wire comes up on the 2wd has a rubber plug, and all the wires are along the passenger side in a cluster of plugs with almost zero slack. Is the o2 sensor plug in there? None seem to match the wire colors on the sensor's end (blue, white, black, black).

My research suggests that before addressing a P0420 code, you should address any other codes first. This case seems like it might be a bad sensor. Maybe the sensor got ruined from the exhaust leak, but then so might the catalytic convertor been ruined as well, age + neglect. This exhaust leak was neglected by the previous owner for so long, the lower half of the manifold shield (upper flange) is destroyed from rust.

I am considering , if I can find the o2 sensor plug and replace it, and the P0420 persists, spraying Seafoam into the exhaust at either the top or downstream sensor hole, or using a similar last resort product that apparently does work for a lot of people.

Worst case scenario, is replace the whole damn convertor + pipe assembly. Looks like someone welded that pipe onto the muffler, but I can probably cut it there with a rental tool and find a way to reassemble.
A potential silver lining is, I now have brand new spring bolts above the convertor, so if I have to go that route, it should be a lot easier. Should. Knock on wood.
Last edited by Vulcan on Thu Jul 16, 2020 8:22 am, edited 1 time in total.
2006 AWD, 207k
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

Using the Torque (lite) Android App, I think the o2 sensors are working properly.

Sensor #1 jumps around from low to high and back again.

Sensor #2 (but which also has the "circuit malfunction" code), once its warmed up, is also jumping around in the same range as #1. (0-0.8v max).

So, I think I need to get an o2 sensor socket and visually inspect that #2 sensor, clean it off, and pop it back in. And obviously wrap the wires better. If I want to pull the #1 sensor, I think I'd need the straight, not offset type socket, because of the rust-weld-omfg situation on the manifold's heat shield.

The car is running so well, and with exceptional gas mileage, that I'm still thinking a can of seafoam in the #1 o2 sensor hole might clean off the converter and allow it to work again for some time. It's not clogged up in any way I can determine.
2006 AWD, 207k
jolt
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Re: AWD o2 sensor 2 plug - ?

Post by jolt »

Info on P0420 code: https://www.engine-codes.com/p0420_toyota.html and https://www.700r4transmissionhq.com/p04 ... a-corolla/

Read carefully as the code most likely is not the sensors your looking at but something else. If both sensors are showing the same voltages and pattens then the cat is not doing its job and the ECM will trip that code.
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

Thanks, jolt, that's about where my thought is on it. It *seems* that both o2 sensors are working right , and the #2 sensor being a recent replacement makes it less likely its not working .

Torque Lite is having a lot of problems talking to my OBDii transmitter, at least on my particular phone. It won't connect at all now. So right now I'm trying a few different apps and also an iPad. It works flawlessly with newer phones and devices. Eventually I'll find something that connects.

I'm going to try to clean the converter, there seems a decent chance that could get some more life out of it.
2006 AWD, 207k
zbyers
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Re: AWD o2 sensor 2 plug - ?

Post by zbyers »

First, I'd take care of the low voltage code... Ensure your wires are all connected properly, and the sensors are functioning correctly.

Outside of that, P0420 99.999999% of the time on these is for the first cat. On the AWD, the first cat is in the manifold, so you'd have to replace that.
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Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

zbyers wrote: Mon Jul 06, 2020 11:46 am First, I'd take care of the low voltage code... Ensure your wires are all connected properly, and the sensors are functioning correctly.

Outside of that, P0420 99.999999% of the time on these is for the first cat. On the AWD, the first cat is in the manifold, so you'd have to replace that.


I've got the o2 sensor code cleared out, and not returning. It's just 0420 now by itself.

The #1 o2 sensor was going very rapidly up/down. #2 sensor was staying at .2v, but every so often, would spike to match the level of Sensor #1.

I tried cleaning the system by putting a gallon of lacquer thinner in a 1/2 tank of gas. (per Scotty Kilmer) This stabilized the sensor readings noticeably in my OBDii App's graphs. Sensor 1 has the same pattern, low/high/low/high, but less frenetic. Sensor 2 is much more stable now at .2v. When Sensor 2 spikes, it doesn't go as high, peaking around .4v now.

I topped off the gas tank (with regular gas), cleared the codes, and drove home. It took about twice as long for the P0420 to come back on.

So, I think I cleared some crap out of the system with the lacquer treatment, and the sensor data seems to back that up.

The manifold-converter for a 2006 AWD Vibe/Matrix is sold by one, and only one, Canadian seller who is currently on vacation. It's $380 USD. The listing says "if your vehicle is registered in NY or CA, do not buy this item". This seems to suggest they will ship it to NY, and are covering their posteriors. I've asked the seller if they will indeed ship to NY.
I can't find one for sale anywhere in the USA. I've only had this car for 30 days, the inspection is lapsed, I'm out of work due to you-know-what-virus, so this is all a bit disconcerting.

I'm going to keep trying to clean out the converters. Despite the positive direction of the result, I don't think I'll use lacquer again so soon. It's still in the gas tank now, and I don't want to overdo it. What I think I'll try next is to pull the #1 o2 Sensor, and blast a whole can of Seafoam into the hole, wait a while, and fire it up. This has cleared 0420 codes for a lot of people. I don't want Seafoam in the engine itself, but this is past the engine I'd be putting it.
2006 AWD, 207k
zbyers
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Re: AWD o2 sensor 2 plug - ?

Post by zbyers »

Yeah, the AWD manifold is hard to get ahold of. IF he won't ship to NY, feel free to ship it to PA and come get it..Not sure where in NY you are, but I am about 2hr south of Buffalo (across from Jamestown, NY). I could ship it back to you if you cover shipping.

Partsgeek has one listed for a lot of monies.

https://www.partsgeek.com/gbproducts/DC ... wuEALw_wcB

as a last resort, you could use www.car-part.com to search junkyards for one close to you.
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Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

zbyers wrote: Tue Jul 07, 2020 3:45 am Yeah, the AWD manifold is hard to get ahold of. IF he won't ship to NY, feel free to ship it to PA and come get it..Not sure where in NY you are, but I am about 2hr south of Buffalo (across from Jamestown, NY). I could ship it back to you if you cover shipping.

Partsgeek has one listed for a lot of monies.

https://www.partsgeek.com/gbproducts/DC ... wuEALw_wcB

as a last resort, you could use www.car-part.com to search junkyards for one close to you.
Thank you, I was just sitting here sipping coffee and not finding any US seller. Partsgeek price is 100-200 higher than the Canadian ebay seller. Whats strange to me is, the Canadian seller has a listing for Toyo Matrix(awd) @ $280+14 shipping USD, https://www.ebay.com/itm/2003-2006-Toyo ... %7Ciid%3A1 and another listing with the same picture for Vibe(awd) @ $320+14 shipping USD. https://www.ebay.com/itm/2003-2006-Pont ... %7Ciid%3A1

40 bucks difference is not that significant to me, but being new to these Toyo/Pontiac collaborations I have to ask, are these the same engine?

I did search car-part, it's been a great resource over the years - Came up empty there so far. I'm looking for a you-pull junkyard locally as well, if not for a used manifold/cat, for an upper heat shield since mine is in such bad shape it may never go back on properly once its off.

I am next to Syracuse, NY, and appreciate the offer to help with roundabout shipping. I'll be in touch if needed!

I'm sure this catalyst damage was hastened by the untended exhaust leak which was right on the cat's flange. It didn't throw the P0420 until the leak was fixed! :P
But another possible piece of evidence is, when I changed the oil upon first buying the car, it had a quick-change oil sticker in the windshield. The owner said he'd always changed it on time and I don't think that was false. But the sticker read "10w-30". Could be a simple error, or the Jiffy Lubers might have been putting 10w-30 in an engine that clearly calls for 5w right on the oil cap :|
2006 AWD, 207k
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

Found the local u-pull, they've got 6 Vibes of the right year, and one Matrix. Doesn't specify if they are AWD so I'm going to take a look before it gets any hotter out today ~

Might end up pulling off some struts as well if this goes well enough
2006 AWD, 207k
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

Looked a 7 Vibes in the junkyard and 1 Matrix, one Vibe was an AWD.

What I found was that the upper manifold heat shield on that AWD was in similarly bad condition to mine, totally disintegrated on the right side. It probably had the same exhaust leak, and maybe the same problem led it do the junkyard when the owner couldn't get a part.
Exterior was in much nicer condition than mine. Same year. Struts looked like garbage. It had what looked like a brand new radiator in it.

It's a bit of a gamble assuming the exhaust leak is what fried the upper catalytic converter, but makes sense as its right on it. But I realize I could replace that top cat, and still fail emissions.

I got an straight o2 sensor socket so I can pull the top o2 sensor without removing the heat shield. And a can of Seafoam top engine spray. Going to blast the bloody hell out of that top converter, let it soak for 20min, fire it up, and hope for at least a temporary fix. I don't think it can do any real harm to try.
2006 AWD, 207k
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

well thats been a very long day. I looked over 8 Vibes in the junkyard, found one AWD, same year as mine. I didn't manage to get anything from it, but at least I know it's there.

The Canadians got back to me, and yes they will ship the Unholy Exhaust components to NY. So that's good. I could get manifold/cat, 2nd cat/pipe, and even add in the midpipe/resonator for about the same price as partsgeek lists just the manifold/cat.

So that's good news. But its not only illegal to buy or sell in NY, but also illegal to install. So unless I can tackle this myself, I'd have to find a shop willing to install without asking the wrong questions.

I pulled the top o2 sensor today, and could see the manifold/cat looked fairly good from what I can see. No carbon in it. I thought I could see a few of the pores plugged up. Obviously you can't see much through the sensor hole with a flashlight.

So, I went ahead and seafoamed right in to the upper cat, through the sensor hole. I used around 1/2 a can of the upper engine cleaner seafoam.

The car seems to have more power now, smoother, but this has not stopped the P0420 coming back. People who have done it have mentioned they've used a full can or more in multiple attempts and it has fixed the code for them, sometimes for a year or more.

But watching my scanner app, the #2 sensor has become much less stable, jumping all over more frequently, and when it is stable, it reads much higher voltage than before.

Being a hack, I'm not really sure what it's supposed to do. I thought #2 sensor was supposed to stay low, and that indicates the catalyst is working. This is what happened post-lacquer treatment, it was very stable around .2v, with only the occasional trip north of there.

I'm wondering if what has happened is, blasting out the top converter has sent a lot of junk into the second one.
So I might pull the #2 sensor tomorrow, and do the same thing to the lower cat, except I'd be blasting backwards into it which is less optimal. I suppose I could drill a hole just upstream of it, and then plug it with a screw, or use the exhaust wrap I have onhand.

I've got enough money into the car, and relatively little money left, that I'm willing to keep at unconventional but old-school solutions to just get a year or two out of the deal.

It just sucks that a car running so well, indeed improving with the cleanings I've been giving it, has an illegal exhaust because of what? I feel doubly abused by not only a dishonest seller, but the unthinking State that would send 35mpg cars to the junkyard and call that "green". :|
2006 AWD, 207k
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

Just went for a spirited drive today, aka the "Italian tune-up".
The #2 sensor has calmed right down, and is a steady .1-.2v for the most part. I think the jumpy readings yesterday were the lingering effects of the seafoam experiment.

I'm just going to drive it for a few days, a little harder than I normally would.

I messed up a little with the lacquer thinner - you're supposed to keep driving it til the lacquer'd gas is mostly gone, then fill it up. I only ran it for 30 minutes @2000rpm on 1/2 tank + 1 gallon thinner, then filled it.

With the o2 sensors seeming to read right, and the car running good, there's still a chance this might clear up over a few days. Meanwhile I'm asking around the local small shops if they will install a direct-fit, OEM exhaust system that the customer has purchased.

If I can't get the P0420 to clear by the end of the week, I'll probably order both manifold/cat and the 2nd cat/pipe together.

I don't think I need new sensors, they seem to read properly now. But with 190k on the car, replacing both sensors myself might be a good move. Because if I end up needing new exhaust anyway, I think its recommended to start with new (or almost new I guess) sensors.
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jolt
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Re: AWD o2 sensor 2 plug - ?

Post by jolt »

Another read for you that you may be interested in: https://www.autoserviceprofessional.com ... -p0420-dtc

You may pick up some info that may give you some ideas. The above talks of Toyota P0420 toward the end of the article, and a Toyota is what a Vibe is. When it comes to the electrical system and sensors on the Vibe, use Denso parts. Denso designed the electrical system and other brands can cause weird issues, ie your oxygen sensors. The rear sensor should be a steady voltage for a given engine load. It should not be jumping or doing the wave if the engine load is steady. The voltage will change as engine load changes. Typical voltage range is 0.0 to 0.8 volts from the rear sensor as engine loads change. That is if the cat is good and doing it's job.

I seen the word extension in the story above showing how not to fix the problem, which it does not, but spark plug extension were used to keep spark plugs from foaling out. O - I am getting off topic now, just read the article above and think about looking for info on Toyota Corolla P0420.
Vulcan
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Re: AWD o2 sensor 2 plug - ?

Post by Vulcan »

jolt wrote: Thu Jul 09, 2020 8:03 pm Another read for you that you may be interested in: https://www.autoserviceprofessional.com ... -p0420-dtc

You may pick up some info that may give you some ideas. The above talks of Toyota P0420 toward the end of the article, and a Toyota is what a Vibe is. When it comes to the electrical system and sensors on the Vibe, use Denso parts. Denso designed the electrical system and other brands can cause weird issues, ie your oxygen sensors. The rear sensor should be a steady voltage for a given engine load. It should not be jumping or doing the wave if the engine load is steady. The voltage will change as engine load changes. Typical voltage range is 0.0 to 0.8 volts from the rear sensor as engine loads change. That is if the cat is good and doing it's job.

I seen the word extension in the story above showing how not to fix the problem, which it does not, but spark plug extension were used to keep spark plugs from foaling out. O - I am getting off topic now, just read the article above and think about looking for info on Toyota Corolla P0420.
Very informative article, thank you! They do show the spark plug non-foulers used stacked together in such a way that the EPA would not like. It doesn't say whether it works, most sources say it does in many instances. It seems from the article that Toyota ECUs, being more stringent on the downstream o2 reading, are the prime target for such "unconventional modifications".
I have even seen where people have , to fool the Toyota P0420, wired a resistor into one of the o2 sensor wires itself, inside the car, to smooth out that voltage reading to the computer. Or physically plugged the sensor with red RTV to get a similar effect.

To answer my own initial question - where is the #2 AWD sensor plug? I finally found that answer. https://www.youtube.com/watch?v=w0WUeDs ... e5w03c010c[/url] on the 1st Gen AWD Vibe, the downstream sensor plug is accessed essentially by removing the passenger front seat.

But anyway, since I'm still trying to fix the problem, and not band-aid it, there will be no "unconventional modifications" as yet. I think these AWD's are rare enough , this one seems to run like a champ and its worth keeping on the road/ investing a bit more. I paid up too much up front, I saw the seller had a disabled kid on the porch of his house, poor/working class neighborhood same as me, and just said efff it, gave him his full asking price in cash. They were able to move on that money.

I thought my attempts at cleaning out the system were unconventional, but it turns out they are recommended by Toyota, and can temporarily fix this problem 50% of the the time! Scotty Kilmer was right again. Looks like I rolled a 51 though :|

The Toyota computer being strict on downstream o2 is probably why the P0420 is still showing despite the same computer reading good on all emissions tests, including "catalyst" is green. That seems like a software failure to me. So I can see why re-flashing the ECU is a Toyota recommended procedure.

In fact it looks to me like the next step is to
check the LTFT's, (+/- 6% )
check again for any other exhaust leaks that might have been hidden by the loudness of the flange one, and the intake side,
check for the slightest misfires/spark plugs,
read the o2 sensor graphs some more, ? pull/replace downstream o2
and finally, update the car's software - scary, but is what Toyota is telling us about their cars, looks like the same general procedure as a firmware update on any other piece of hardware, only the stakes in having a file transfer/reboot error are high. They might have been releasing the firmware updates in response to how the cars are performing "in the field", and as they age, so a 2006 might well have a later version available. And since Toyota is not Microsoft, software updates are probably a good thing.
2006 AWD, 207k
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

Allright well just gathering more data, once warmed up the car is

-7.8% long-term fuel trim at idle, about -2.4% with giving it any throttle. Is the idle LTFT a problem??

the downstream o2 sensor is staying 0.02-0.2v anywhere between idle and 2500rpm, except when you step on the gas, then it spikes momentarily, and takes a while to settle back down but goes down to .2v even with the RPMs maintained.

This is the sensor that was saying it was "low voltage" before the exhaust leak fix.

Spraying bursts of brake cleaner around the intake manifold with it running didn't seem to do anything at all.

Upper heat shield has come really loose, going to secure that and then drive it some more.

I couldn't get anything on the emissions test screen when hooking up to the OBDII this time. battery hasn't been unhooked or anything, so I'm not sure why this is. For codes all it still has is two confirmed P0420 and one pending.
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Mark
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Mark »

The spark plug anti-fouler stack cleared the P0420 code on both a 2000 Corolla I had and also on Frosty at about 185k.
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Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

Mark wrote: Sun Jul 19, 2020 1:47 pm The spark plug anti-fouler stack cleared the P0420 code on both a 2000 Corolla I had and also on Frosty at about 185k.
Thanks Mark, good to know. I may end up taking that route, but not until I've ruled out the sensor.

While the car seems to run great to me, what do I know. I figured a new set of Denso spark plugs (I got the "power" plugs with the 3 blue rings) couldn't hurt. I sourced out some new Denso ignition coils and MAF if I end up needing them, but for now I just want to see what condition the existing plugs are in, and whether they indicate a "lean" condition.
2006 AWD, 207k
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

So yesterday morning, I'm going through the old toolbox, and I thinks to myself, "what the hell did you use this for, Dad?" , being a very long wrench extension bar.

Fast-forward to later in the evening, and I'm about to change the spark plugs on the vehicle (the Vibe I'm working on is my only transport), and that question answers itself. Times like that, you feel like they're still with us.

So what I found was, a set of NGK ("IR", MiJ) plugs in the car, all them with a white haze and a slight blackening on the upper diodes. This seems to corroborate the OBD2's apparently out-of-spec "lean" at idle, -7.8%, and only +2% throttled up. But the haze could also have been from the lacquer thinner and/or Cataclean treatments. They were also slightly worn on the inner diode, increasing gap a little, but I think they'd work fine if cleaned up and re-gapped, so I kept them for now. If the new plugs foul up right away, I might have to clean/regap/rotate between the two sets until any problem is figured out (or learned to live with).

But the new plugs I installed are Denso "power" iridium. I spent several hours cleaning the engine bay before installing the new plugs. On the engine's right side there is still a sticker, I have no idea how they engineer STICKERS that will stay on an engine for 16 years! - that once cleaned off says clearly to only use iridium plugs in the engine. I wanted to clean off the sludgy areas around the valve cover, especially that spot where everybody who doesn't put a rag is going to dump oil right down the front onto electrical connectors, which were so sludged I didn't see at first.

I used mostly brake cleaner sprayed into the rag, not haphazard, on the engine and metal areas, and electrical cleaner to douse the connectors. Then I've also been using Silicone spray on all the hoses, rubber, and plastic parts.

The brake cleaner (idk why but I have 3 cans) was also just the thing to get an ugly sideswipe of paint off the side of the car, and did some small wonders on the headlight housings.

I got the car all buttoned down, then realized I never put the 4th new spark plug in. Doh! Thank goodness I didn't try to start it like that! :lol:

So, I didn't kill anything, it starts right up. To my ear, it does sound just a little bit smoother.
I also installed a new Purolator One air filter. The filter media's "ribs" look about 2mm thicker than the generic one I took out. 2mm x the number of "ribs" = a lot more filter...

Then, I re-organized my toolbox, and put the explosive things like the MAP fuel in the shed. Going to need that stuff to heat up the downstream o2 sensor. And I bet it's great for starting a fire in the fire pit. We had a massive burn the other night, rotted tree fell. It reminded me of drum/dance festival fires in the 90's :mrgreen:
2006 AWD, 207k
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

result of spark plug + air filter change: LTFT improved from -7.8% to -5.4% Now it is within the +/- 6% mentioned in Toyota P0420 article linked above.

Can't tell what is placebo, but going for a drive, it feels much smoother on accelerations, and slightly more power. 8-)

But - additionally, I spent more time watching the #2 O2 sensor, and saw it flatline totally, for several minutes, even when revving up the engine in the supermarket parking lot. Eureka! The sensor, or its wiring, is almost certainly failing after all!
Then when the sensor does come "to life", it's reading 0.02-0.04, even with throttle, its barely responding.
I got it to "flatline" again after driving home.

I don't know why the ECU isn't giving a P0136 again, even with the flatlining sensor it only reads P0420, but they are related , and with a little good luck I might have this code cleared out after replacing the sensor.
2006 AWD, 207k
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

Finally managed to conquer the o2 sensor replacement.

Finding the plug took longer than replacing the sensor. First I unplugged it, and then fed it back down through its hole.

Three long hits of the torch (my first time using one), some PB soaking when still hot (wear a mask!). and then the closed end of a 7/8 wrench hit with a hammer - out it goes

the old sensor was a Denso. But the design was different on the old sensor. It had a different "nozzle" configuration, with far less holes.

This concerned me enough to stop and double-check the new sensor's Part No. , and that it was for AWD. The new one checks out. It's a 14-year old car, maybe the design of the sensor has changed since then.

I re-installed it, and took about a 30-minute evening drive. Light has not cleared, but it wasn't that much driving.
When I got back, I hooked up the iPad, engine still hot.
The new sensor bottoms out about the same , 0.02%. I noticed the graphing seemed more responsive, it will rise slightly with mild throttle, and it will jump a little if you really goose it, then immediately stabilize. I didn't see any dead activity.
I checked the codes, and one thing has changed: there is no longer a "pending" P0420. The two "confirmed" are still logged, but all along it's been also showing a "pending". Which I think means, it's not finding the fault in the current cycle, and the computer may turn off the CEL with a bit more driving. Or that if I clear it, it won't come back on. I'm going to drive it a good bit more and see if it sorts itself out.
2006 AWD, 207k
Caretaker

Re: P0420 , starring a NY 2006 AWD 190k

Post by Caretaker »

Vulcan wrote: Tue Jul 21, 2020 7:07 pm the old sensor was a Denso. But the design was different on the old sensor. It had a different "nozzle" configuration, with far less holes.
This concerned me enough to stop and double-check the new sensor's Part No. , and that it was for AWD. The new one checks out. It's a 14-year old car, maybe the design of the sensor has changed since then.
Yes, that actually is not uncommon. We are all aware of Toyota changing to the orange intake manifold gasket; they also have redesigned the throttle body slightly on the Corolla 1.8 liter engines should you ever need to order a new one.
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

So, this change of design suggests it might have been the original o2 sensor. The condition of the wiring below the car looked so clean, and it was dangling in a haphazard way, that I though it had been a recent replacement. But the condition of the sensor inside, is far worse than the top one was. The top one looked fine.

One more important tidbit I've learned about o2 sensors - the voltage DROPS as oxygen INCREASES. So a consistently low reading when the engine revs up ,means high o2, suggests catalyst failure, and the computer flags it P0420.

So I might not be out of the woods on this, as the new sensor still reads low, but it did remove the "pending" code.

I'm tempted to just clear the DTC, then then take it out on the highway to help the internal emissions tests along. I know that for the previous gen of Toyotas, the computers are looking for 10 minutes of highway speed to finish emission checks.
2006 AWD, 207k
Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

It took a few days for the computer to get used to the new o2 sensor, but I'm right back where I started now.
All internal emissions green, including catalyst, but still stuck with P0420's. Two confirmed, one pending.

I spent over an hour trying to drill out one of a set of spark plug defoulers, to try that remedy. I have a drill bit large enough, but don't have a drill that will accept it. So its just bloody murder trying to ream out enough metal to get an o2 sensor in there.

Realized last night, I've been having non-stop car problems for over a year now. Not 2 days into owning this Vibe, it starts this P0420 BS and I'm 2 months into driving it with an expired inspection.

I like cars and its interesting , but I'm really just sick of it all at this point. Maybe leasing is better than throwing endless hours at these old junkers, even if they're cute and worth fixing up.
2006 AWD, 207k
Caretaker

Re: P0420 , starring a NY 2006 AWD 190k

Post by Caretaker »

If you are in need of some inexpensive wheels and drive mostly city/around town, go get any used Honda Fit. They are indestructible. The OEM parts in the first and second generation Fits are beyond compare and as such, owners who ignored regular fluid changes and beat on their cars still can't break them. I think the added noise insulation was added in 2012. I'd start with that model year for worry free driving.
Mark
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Mark »

Vulcan wrote: Sun Jul 26, 2020 8:36 am I spent over an hour trying to drill out one of a set of spark plug defoulers, to try that remedy. I have a drill bit large enough, but don't have a drill that will accept it. So its just bloody murder trying to ream out enough metal to get an o2 sensor in there.
I've done it twice now and it can be a massive pita. You have to start with a bit just large enough to fit the hole or very slightly larger, and then keep working up until the hole is large enough. I think 1/2" was the largest size I needed, but until I downsized and started gradually enlarging the hole all I did was burn up bits.
'08 Base Stealth, '05 Base Satellite
zbyers
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Re: P0420 , starring a NY 2006 AWD 190k

Post by zbyers »

Mark wrote: Sun Jul 26, 2020 1:16 pm
Vulcan wrote: Sun Jul 26, 2020 8:36 am I spent over an hour trying to drill out one of a set of spark plug defoulers, to try that remedy. I have a drill bit large enough, but don't have a drill that will accept it. So its just bloody murder trying to ream out enough metal to get an o2 sensor in there.
I've done it twice now and it can be a massive pita. You have to start with a bit just large enough to fit the hole or very slightly larger, and then keep working up until the hole is large enough. I think 1/2" was the largest size I needed, but until I downsized and started gradually enlarging the hole all I did was burn up bits.
Agreed. When I have drilled out similar things, that was the exact route I went...After hitting it with a center punch to get started.
'74 Thing, '79 El Camino, '83 VW DoKa '91 Vanagon, '03 Base, 04 GT
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Vulcan
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Re: P0420 , starring a NY 2006 AWD 190k

Post by Vulcan »

my last post was venting frustration, but I don't give up.

I bought a premade o2 spacer from ebay, which took a little extra time to arrive. Spray painted it black, and installed it quite easily, since I'd already removed the old o2 sensor.

About 24 hours later, the CEL went out on its own. :mrgreen: I've driven about 300 miles since. The P0420's are still stored, but the light remains out.

I brought the car in for a new tire, got an alignment (it was waaaay off), and also paid 50 bucks to have them remove all the dented/distorted/destroyed lug nuts, and install the new set I had already purchased. Now I can finally remove the wheels myself, and do some TLC.

Knock on wood, should be "legally" inspected by the end of the week.
2006 AWD, 207k
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