Yet another P0420 code

Dirt cheap, I just did both temp sensors a few months ago, BeckArnley , less than a 20spot iirc.

 

Hmm, looks like it's $50-60 using the part number Noah posted here. https://autoparts.toyota.com/products/product/sensor-water-temper-8942220010

 

Beck Arnley. There's your problem

 

Lol, I'll look it up when I get home.
Of course I got them from CockAuto...

 

Oh no, I've had no problems since installing them, they actually fixed innacurate data...
OEM Nazzi!!!!

 

I just don't trust Beck Arnley parts. They're on my shitlist. Prior experience. Twice. Screw me once, screw me twice, yadda yadda. And for anything electronic, I'm trying to go OEM unless it's really a wallet-breaker.

Looking at the list of what's out there, I can't tell who the OEM is on that one. I can't imagine Toyota is making it in-house. I'd expect NTK (subsidiary of NGK) would be the OEM on that part, but clearly the brass body is different. No doubt Toyota is charging waaaay above the "premium" brands (Delphi, NTK/NGK), maybe they actually are in-housing that one.

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$22.32 for the two of them. Working perfectly. I forgot how brittle my Sensor was (randomly dropping signal to ECM), the sender was fine.

 

Where does the dash gauge read for the grey sensor that goes to the gauge cluster?

Got a DMM to check the green one for accuracy? For 2UZ:

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And FSM offers up this process also:

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Thanks for the info Shifty
Yeah the grey small sensor is for the cluster gauge, and Green one is the sender for the ECM.
I have a couple DMMs, I never checked it since installing. But the old one was dropping out on the OBD2 data.
And you can see on the break the only portion that was holding on was the bits of green/freshly severed.
When I finish burping the system ill check the temp on the OBD2, then go right to the sender and check the resistance and see if it's in range.
I've got a laser temp reader at work I could employ too.
EDIT: Originally I though this might be kicking me out of closed loop, and in turn making a rich fuel mixture... leading to the 0430.

 

I decided to take a closer look at my water temp sensor. The plastic housing appears to be cracked. How bad of a crack?..i dunno, but the plastic portion of the sensor is wobbling around a bit on its brass housing. I'm trying to figure out just which sensor is which for my truck. Toyota shows that the 2000 truck uses a different sensor than the 2004. I think it's just the shape of the connector fitting? Rockauto shows that all the 1st gen uses the same sensor...i don't believe them. I'll probably just buy toyota oem so that i don't end up playing (and loosing) at the game of buying the wrong shaped part that's supposed to fit my truck. Me thinks it's this one... https://toyotaparts.ourismantoyotao...9dHVuZHJhJnk9MjAwNCZ0PXNyNSZlPTQtN2wtdjgtZ2Fz

 

What year is the engine?

If you still have the OEM part installed, it should have the 10-digit hyphenated part number on the collar, like you see here - it's best to order your replacement using that number, assuming nothing is really changing, harness is the same connector:

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Engine is a 2000. Engine harness is a 2004. When i did the engine swap i accidentally broke off one of the brittle temp sensors off one of he engines. The only problem is that i can't remember which engine i broke the sensor off in. I think(?) i ended up swapping the sensors between the two trucks. I just took a look at both my old 2000 harness and 2004 harness, and both connector ends look the same.

EDIT: I just removed the destroyed connector off of the parts truck P/N 89422-20010. The only problem is that i don't know which truck that originally came off of (2000 or 2004). I guess i need to remove the sensor off of my 2004 truck and check the part number on it. But i'm not really in the motivated to drain the coolant to get to that sensor.


2nd EDIT: I just got lucky...i cleaned up the currently installed temp sensor that's in the 2004 truck with a toothbrush and lacquer thinner. Using a flashlight and a mirror, i found the P/N 89422-30030...which is a different number from the 2000 truck. I what way i do not know.

 

Actually, I can't be sure, so I'm just wiping my previous comment out. I need to dig more, but stuck on a task that prevents me from digging at the moment.

 

Update: So it's been over a week since the cats were replaced and p0430 came back. Which is odd to me, because p0420 has always come first for this truck. So I'm at a loss. I found an O2 sensor spacer that fits the old oval style sensors. I guess I need to order a gasket or two now.

 

Surprising. Intake/exhaust leak is the next culprit here, I believe. And it's assuming you got the de facto correct part for your ECU. I suppose potentially vacuum also, but I'd expect exhaust leak.

 

I think it's the cheap mystery cats not playing well with the ECU. Supposedly the shop already checked for a leaks a few weeks ago. Granted there could be a leak now since they swapped the cats. Either way I'm about ready to wash my hands of it. I tried to be legit and spent a lot of time and money replacing cats and sensors. Now this is a 21 yr old truck and the state of TX emissions test is due next month. So they can suck it. Haha

 

Im late to this thread but just wanna say a spacer is gonna be your easiest and cheapest thing to try first to get rid of a P0420... sounds like your cats are toast and instead of welding/washing/etc just bolt on a spacer and see if that fixes. If you get a kit with extensions, don't use them extensions, just bolt it up so the O2 sensor's tip is lined up with the exhaust pipe wall and it'll do the trick. The extensions will give you a P0136.
Sorry to all if the discussion is way past this, I barely understood a lot of what you guys are talking about.

 

So what’s the difference between an o2 spacer and an o2 extension?

 

I have O2 wire harness extensions because my long tube headers move the cats back further than stock. So I needed more wire to reach em and these are.plug n play harnesses. I assume that's what an O2 extension is a reference to.

O2 spacer depending on your year model and sensor style is this or this

 

This is what I mean, the red circled part and maybe the blue circled screw on nut for the long-threaded portion (but probably not, depends on each particular kit).
Basically you should do one flange bracket screwed on each side of the double-threaded tube. One flange goes on the exhaust pipe, other side flange is what you'll bolt your O2 sensor into. Thats what I mean by "spacer".
By "extensions" what I mean are the un-circled other hollow tube and the right angle joint pictured, and perhaps the blue-circled spacer nut as well. Dont use those.

You'll have to buy basic cheap flange gaskets as well if you dont have any on hand, I picked up a couple from my local irish-themed auto parts store.
If your O2 sensors dont use the flange bracket style, then you should just be able to direct-thread the spacer into the pipe.

I tried the "extension" parts and it threw a P0136 code on me so this is my own experience telling you to use only the single hollow double-side-threaded tube piece and none of the others from the kit.

 

I think your issue is most likely due to running DIFFERENT ecu. How did you address the difference in the " Accelerator Pedal Position Sensor" when doing your swap. Your 04 motor ECU "APPS" is integrated into the pedal DBW system itself. Just that alone could be messing with fuel trims. Based on logs provided in your post , if you dont have large leak...you leaking voltage or its related to (apps, cts, ckp as mentioned) . With german cars i used to see this exact same issue with cts issues. ...hearing your bed is off it could be a number of things. Is your ckp retaining bolt tight? On a scale of 1-10 how thoroughly did you inspect entire wiring harness. Did you check all your ecu pins ect? Live voltmeter testing is your best bet. Looks like damaged wire or ecu compatability issue at a glance. Gl with fix. Def check your warm upstream voltage readings and see if you can borrow laptop with techstream app on it to capture data better ( what dealerships mainly use) just my opinion.

I would live check it with voltmeter while on jackstands. Sounds like you have done a great job troubleshooting everything else.

 

What i’m curious about is how to go about finding out if there’s an exhaust manifold leak or crack. That manifold is just about 100% completely covered by sheet metal heat shielding. Like even with a flashlight and mirror you can’t see very much of the manifold tubes.

 

Thanks for all that input Bluegrape. Yes i did install a 2000 engine into a 2004 truck. But i installed the 2004 DBW and throttle body onto the 2000 engine. The 2004 truck still has ALL the 2004 computers, ECU’s, body harness, DBW pedal, ect, ect. What i did was just swap the 2004 engine sensors AND 2004 engine harness onto the 2000 engine.

As for how well did i inspect the 2004 engine harness? Well i bought it from a wrecking yard (on fleabay). Though i didn’t check the continuity of the wires, i did inspect the whole harness VERY closely multiple times over. I saw absolutely zero corrosion on any of the terminals. I also didn’t see any signs of the convoluted tubing (what wraps around the harness) crushed or damaged in any way. I then spent a considerable amount of time VERY thoroughly cleaning the 2004 wrecking yard harness (it was fairly clean, but i wanted it spotless). I reinstalled the bed back on the truck last month.

As for the rest of the harness on the truck, i spent many hours on my back rolling around underneath the frame closely inspecting everything...and i mean EVERYTHING. I didn’t see any sort of damage to any portion of the harness. I also didn’t see any sort of previous body damage on the 2004 truck that could have caused damage to the wire harness. I also looked over the inside cab wire harness when i had ALL of the interior removed. I didn’t notice any damage to it. I also have not seen any random errant sheetmetal screws that could have pierced any of the wires.

I did NOT ever check the 2004 ECU pins. I can check them tomorrow.

I’m 100% confident that the ckp retaining bolt tight, but i’m not 1000% sure. I can double check it tomorrow.

I just installed a brand new OEM toyota Coolant Temp Sensor this afternoon..to no avail (my CEL still turned back on).

Checking voltage with the techstream app on a laptop would be a challenge for me. I’d probably have to take my truck into a shop and have them do that.

I’m kinda dragging my feet to buy a replacement catalytic converter. Seems like everything is pointing to it, but my fear is that once i install a new one, it still won’t keep my CEL from turning back on. I’m tempted to just try installing an o2 sensor spacer, but i’d like to get to the root of the CEL problem.

 

UPDATE: my new OEM toyota water temp sensor arrived today in the mail. I don’t know if my old WTS was working or not, but since the plastic body was loose on the brass portion of the sensor, it was definitely compromised. After installing the new WTS the CEL turned back after a 20 miles drive. My next plan is to remove the 2004 left side pipe/cat, and reinstall the 2000 left side pipe/cat. If the CEL turns back on, i’ll look closer at replacing the cat next.

 

You'd hear it ticking.

 

Smoke test is your best option, IMO. While you may not be able to see the exact leak spot behind the shield, it should be pretty obvious if air is passing by, I think? Pass the smoke in at one of the vacuum hoses at the TB for intake, and at the upstream O2 bung for exhaust.

 

During my google searching of smoke machines, i found out that Harbor Freight will be releasing a smoker for sale Spring of 2024. I don’t know any other details than that.

 

I have noticed every once in a while that i catch a tiny whiff of gasoline when i’m getting out of the truck. It’s faint enough that i usually only get one chance of smelling it. Then it seems to disappear. I checked my brand new gas cap, and the smell isn’t coming from there. There’s also zero wet spots at all of the fuel connections. I reinstalled my 2000 left pipe/cat last night. I’d drive the truck around tomorrow morning and see if my CEL turns back on again...which no doubt it will. If/when it does, i’m thinking about welding in a used random catalytic converter that i found in my shop. It can’t hurt to weld to weld it into place. If it doesn’t work, well that means i can remove it and get rid of it so that it isn’t taking up any space in my shop.

I have no idea where the cat came from. I’m thinking it was from a random jeep project that i bought? Check out the all the dingleberries that someone welded to it! Embarrassing to say the least!!





I also took a closer look at the 2004 ECU. All the pins looked perfect and i didn’t see any sort of corrosion or any other red flags. And yes, i check the crank position sensor and its retaining bolt was tight.

 

I would buy a " spark plug fouler" or two of them. Last time i bought one they were $2.99 a pop. So you could basically check your cat for 5 bucks. They work identical to the spacers. Any autoparts store should have them. That way you can cross off (or on) the big ticket item.