Oh, it's a frosty day for a Chevrolet What? this thing? 2500 HD 2001 Oh, that didn't sound good. Oh, door just fell down a foot. she's a little loose. Let's see how many miles are on this Pig 145 and apparently it runs like poo when it's warm.

Oh boy, it's got the Chevy manifold, tick the broken gas gauge, the ABS light. Well, let's bring it in and let it warm up and see what happens. Let's see what we have under here. The big SE All looks like it's already got the new plugs and wires and a new coil.

So it's got at least a new coil or a couple new coils from the looks of it. Well, actually, maybe all the coils. Yeah, it looks like all the coils are brand new. Um, new wires anyway.

so who knows if the plugs are new, probably would be my guess. All right. Well let's uh, get some cold data just off the scan tool, see if there's any stored codes in it, and then, uh, then we'll let it warm up and see what happens. cuz apparently it runs really poorly.

When it's warm, it's getting chilly out so you guys will have to deal with the uh, furnace running. Oh okay, engine missfire detected and then that's for our broken fuel gauge. So pretty common. Um, well let's just look in live data here and just see what things look like like I Say well, it's still cold I'm just going to take and poke through here.

Actually, our our best bet would be to poke through some generic data just to check like you know, temp your pids and stuff. Um, so that's what I'm going to do I'm going to poke out I'm going to jump in some generic data, make sure everything looks normal. Uh, the reason you don't want to use OEM data is be just in case there's some kind of substituted value. The the generic OBD data is loaded up and I see an anomaly right often right here.

Bank One longterm fuel trim is at 25% longterm on bank 2 is pretty close to zero. So so that's going to tell us what our our problem is right there we're running lean on One Bank Okay, and what we'll do is we'll fire it up here and we'll look at some stuff. I'll get some O2 sensors pulled up here. Um, we want to look at 1 One we want to look at 21 wherever that little guy is.

Output voltage right here. so it looks like we have some O2 sensor issue going on here. We'll get them and then let's look at our fuel Trims and we'll get Coolant Temp and find an engine. RPM All right, well let's go ahead and start it.

2111 problem is on bank one, so let's go ahead and fire this thing up and see what stuff looks like as it warms up. Classic manifold KCK So like I say you can see somebody already shotgun all the coils at it. That was an expensive guess. let's let her warm up here and see what's working and what's not working so you can see we're trying to compensate fuel right now on bank one and it's not responsive I Don't know if this reading for Bank the Bank One Sensor 2.

If this is correct, you can see our bank 2 is stuck in its bias voltage and is trying to pull fuel away from bank 2. Yeah, it's it's. going to have our fuel trims maxed right out here pretty soon, so it's a safe bet to say the Bank One Sensor One action sensor is DOA I Think our downstreams are are likely telling the truth. Okay, so let's let's just look at it like this: Um, uh, I guess we can get rid of.

uh, we get rid of our long terms, just kind of clean up our screen here here. Uh, our mass air flow is over reporting like crazy, but it's still cold so I'm not going to sweat that too much. Um, so our short-term fuel trim right now is Peg Right out running super rich and the Upstream oxygen sensor is is not being responsive. The downstream, however, is saying that it's rich but not not pegged out either.

So that's kind of bizarre. And then our bank two is trying to take away fuel. O2 sensor is stuck you know, at its bias voltage, but the downstream is full lean. Oh, just went into open loop.

that's probably a pit I I Just heard the engine changed tone. it said hey, I'm broke let's see fuel status. Yeah, fuel status went back into open loop. It is super rich I can smell it even though I've got an exhaust tube on it.

Uh, let's go ahead and shut this thing off here. Yeah, you can tell it's rning super rich. I'm going to give it a couple rev up tuneups to see if any of these O2 sensors become responsive. All right.

Look like Bank two censor one starting to come to life I think one sensor two is functional. All right. Well, we've got some dead ones all right before we get affixiated. Let's uh, let's go underneath there and see if these are the OG 20 2-year-old O2 sensors or what's going on.

Let's see, make sure it's not going to fall on her head or she rotted. Oh boy, wow is he crusty. Oh know man, look at that. the OG Nice original O2 sensors yuck yucky yucky Downstreams: I'm not super concerned about they don't play a huge role in fuel strategy on these older sheves.

Uh, the Upstreams however, do. And the reason for the season and the fact that they haven't been changed uh is because it hasn't thrown codes for them. so people only uh change parts that they that the AutoZone tells them to. Wow, Dude, this thing is rotted.

No breakes Yeah boy, you got to know a guy to get a sticker for one of these babies. Brake hose is just hanging. Uh Welcome to New York Son I've got the O2 sensor unplugged here on the passenger side so it's going to be the bank two sensor one. Uh, I've used the scan tool and I've turned on the O2 heater for us.

We need to make sure that our heater control circuits good. Let me get a different test light. We got a uh, just a 194. Now the heater control is going to be the one that has the two wires that are the same color and in this case they're both black on the shorter part of this triangle.

So both of these these two top I've got the O2 heater turned on. This should light a test light if the power and ground here is good. Oops. and if if my eyes can see here, let me move you over a little bit know you're not in the optimal viewing angle.

but it's better than looking at the back of my head I assume. So I'm going to very gingerly that connector. It's got a little bit of corrosion in here. Okay, so there that is our O2 heater.

We should be able to turn that off with the scan tool. Oops. You guys can see it so it's off and that's on. So we've got power and ground going to our heater and this test light here will carry about the same amperage as an oxygen sensor heater.

Uh, the front ones here are are PCM controlled. but I do see a little bit of an anomaly here and I don't know what to think of it. So somebody's poked this wire here. the green with white stripes, so that's our that I think that's our positive side of the Uh heater control.

PCM controls both a highend side. Yeah, so look at that. Somebody poked a hole in. it.

looks pretty fresh too cuz it's still copper. It hasn't turned green yet. Um, but the anomaly I see is I have both O2 sensors unplugged. sorry about that.

Turn that down. So the anomaly I see I have both O2 sensors unplugged Bank One Sensor One is biased at you know, 450 Mt and Bank two. sensor 1 is at 1.1 volt. so that's kind of bizarre.

Um I don't know why I don't know why that is and I don't think I'll find the answer to that in service data. Let's see what we'll do is we'll take our test light on the signal wire here and see if we can pull it all the way to ground. which we should be able to. Uh, let me.

Focus you guys on the scan tool got it highlighted there. Bank 2 Sensor One: Let me come in here and find the signal wire. It's not going to be whoops. Let go my test light.

Hang on. Get over here. It's going to be one of these bottom two wires. We'll try this wire first, not that wire and try it that way.

There you go. 0 molts. Okay, so now to make sure that the uh, censor ground is good. I'm going take the test light.

I'm just going to jumper this across the sensor ground, not the heater ground, the sensor ground, and the signal wire there. and that should also pull it to zero. So I'm just going very gingerly. front probe here.

get it in there and there we are. 0 volts. So we have sensor ground, we have sensor signal and we have the heater control. Uh, so that tells us that we have everything there that it needs to make this thing work.

So let's just go check the other side. This one's way trickier to see. Stick the light there. uh I guess first thing first, let's see, we know that the uh, short side of the triangle is the heater wires.

I Know you guys won't be able to see much, but we'll give you the play byplay if we can get my hand up here. I'm going to jumper across the heater ground and the heater power. Well, maybe there's that one. There's that one and our test light is lit.

We should be able to turn it off so that's off and that's on. That's for for the heater control. Okay, on the scan tool, we're at 450. Ms is I'm going to check these bottom two wires.

One of these will be okay. Oops, it's that way right there. Let me Focus you guys on the scan tool again here so you can see we're at 450 molts there. I'm going to short it out with a test light or at 0 volts.

So that tells us where. going to the PCM is good. Now I'm going to jumper the test light across the censer ground just like we did on the other side. get my probes to stay in there.

there's one and then there's two that sensor ground and it's at 0 volts. Why are the bias voltages different on that one and that one? That's pretty curious I don't know the answer to that for you folks and I'm not going to pretend to know. but I do know that it appears that the wiring to the PCM is good. It has heater control, it has ground, and the signal wires both seem to work.

Um, I Don't know. For some reason I Thought open circuit voltage on these was 450 MTS I could be wrong. We could unplug a back one I Unplugged Bank Two Sensor 2. So R2 yeah, and 450 MTS is the open open current or open circuit voltage, so that's pretty peculiar.

I'm not sure what to make of that just yet. So now now that we know that, it makes me wonder if the signal wire a bank 2 sensor one is is shorted uh, to some sort of voltage. That's the only thing that makes sense cuz like I say when we unplug them, they should be around 450 and give that a thought in the beginning. Um, let me think about this folks.

So how about this? um I'm pretty sure we're going to find some corrosion or something here. The other ones like I say when we open them are 450 Mws which if I like I say if I remember that is that is correct on these older GMS We're going to take a regular voltmeter and we're going to measure voltage across sensor ground. so from sensor ground which we know is good because it has the ability to pull this signal all the way to ground and then we're going to see how many volts we actually have on this. Now your scan tool is only going to read 1.1 We could short this right out to 12 volts and it's only going to go to 1.1 So let's just see what we're looking for here.

see if it gives us any kind of sense of anything. Yeah, so look at that 2 point. Wow, about 2.8 volts so that's that's wrong and it's climbing. I'm going to turn the heater on.

We're going to see if we're as I turn the heater on. Nothing really changes, but yeah, the voltage is going up. So about 2.9 volts. so I think we're probably dealing with there's some kind of cross voltage action going on here.

CU Typically on an O2 sensor, you can kind of lick your finger, touch it across the signal in the ground wire and it will pull them to ground. Now this one doesn't So that voltage that's in there has the ability to carry a little bit of current. Not much because we we can short it with a test light, but this does not change our data pit. Well, it does barely 100 thousand of a volt.

So um I can show you that on the other side probably. So you're going to be looking at this one. So I'm going to use the old lick the old pinky finger, get her a little wet right on the tip. Reach in there best.

you can touch the ground and you see how we're pulling it down to 200 molts. Just just like that I release my finger back to 450. So these S I Guess what? I'm getting at is these circuits are very sensitive even with a high impedance meter. Like if I measure this one see I'll measure the voltage across these shoot.

My leads are pretty short here. Let me see if I can get this up here. I think even with a high and pedance meter it's going to pull down that signal I guess So what what I'm getting at is just that these these circuits are very very very sensitive. Let's see, we're at 450.

MTS Let me just measure across these I'll tell you when I'm on them. Okay on. yeah, you see that even the meter pulls it down to 400 molts. Take the meter off, we're back to 450.

So and then the meter. You guys couldn't see it but was reading uh, 400 Ms also. So we definitely have a short in this in this. O2 sensor in that harness.

Awesome! And and it's probably corrosion. so I'm pretty sure I'm right. I'm going to do some poking along here. Uh, I Got to get out the old creaky step stool, let the furnace run, let things warm up here.

Uh, these were pretty failure prone to have corrosion of. ECM I'm just going to bring the scan tool over here and kind of just wiggle the harness and stuff and see if anything changes. Uh, we know it's not shorted to the heater circuit. It's not shorted the ground like I say I'm pretty sure we're dealing with corrosion.

It's getting some stray current or some straight voltage. uh, from something. And and that's it. I Mean that's that's what the answer is.

It's on the signal wire that's picking up stay voltage. However, it can't carry current because we stick a test light on it. you know, drops it right to zero. So that's why I Feel that we're dealing with corrosion.

That's my final answer. and if I'm wrong, well, we'll delete the video and pretend it never happened. So what I'm doing right now is I'm going to pull out pin number 66. that is the uh signal wire.

hopefully I get it out of here without, uh, do any damage to anything else. Lock is right there. I was thinking I was thinking about just cutting the wire the signal wire to see if it if it corrects the problem. That'll 100% tell us if we're shorted.

Uh, I'm going to sit here I'm going to try to depin it I mean I unplugged It got the cover off. Usually these things pop right out. Um, let me. uh, let me fiddle with this.

We get that unplugged and we can plug it in. That'll tell us for certain 100% without be on a shadow of a doubt cuz I've looked Pride P wiggled and I can't get the data pit to change. so I don't know where this corrosion can be. um or if I'm just chasing a ghost here I Got p 66 is is now removed.

We'll plug the connector back in here on the computer. ever so gingerly turn the key back on and this will tell us. Got to go back to engine Data One: We got to find our Ction sensor. Bingo Bango! think two.

So there now it's open circuited at 450. Ms We 100% for certain have a problem. Let's grab our uh meter here. Okay, let's go uh me grab this wire here that we just unplugged from the PCM and same thing we had down there.

we are two .8 Vol So that's that Now now we got a problem. same problem we had before. it's just for some reason. I I Doubted myself.

just got to find out where. it's just so bizarre because like I say according to according to service data, there is no other connection between here and there. and man, I don't want to go just opening up piles of wire loom. I'm going to do some more looking, but uh, we definitely definitely have a problem.

as you guys can see, so that that just proved it. So hopefully this all makes sense by unhooking this wire here out of PCM So this is essentially just the signal wire and some wees it's picking up stray voltage somewhere is through the harness. um I hate leaving stuff like this alone and just you know, just running a bypass even though the truck's you know, completely rotted. you know will'll never pass inspection in like a million.

oh sorry, it's got a brand new inspection sticker on it. Um, but would never pass inspection in a million years. The smart thing to do would be just cut it and bypass it. but if there's a big green puss set growing somewhere, that would be kind of nice to know where.

Uh, because it's going to affect other wires too. And I think this is the first time in all history I Got one of these wire covers off on a GM and didn't break one of the six tabs. all of them came off. It's L ticket time I've got our meter hooked up up top.

it was at 2.9 now. I'm down here fiddling with wires I just had like a little little something something happen. So let me set you guys up. I'm fiddling oddly enough with the wires here going this direction which should just lead to this rear.

O2 Yeah, that's all they do. They just lead to the rear. O2 I Would have thought these would have turned the corner here and headed straight up. So let me fiddle around back here see if I can get these voltages to change.

It's kind of bizarre. Oh yeah, look at that. look at that boys. I'm going to wiggle I'm down here I'm just behind the connector.

No kidding. Okay, you see that? of course you do. I got you super enhanced. It's time to open up some tables son cuz now it's down to uh.

8.8 Vol So 850 Mt Yeah, it's something. It's something right here cuz it's going all over the place I could see where somebody I think we mentioned. Did we mention earlier in the video there's a hole right here that somebody did the Hokey pokei but that's in the uh, that's in the heater wire. that's in the heater power wire.

Let's see what we got going on now. Yeah, the voltage is all over the place. It just spiked up. Uh well.

p Volts Now it's down to nothing. but we've got to kind of keep going here. Let me unhook the O2 sensor connector. Okay, get that out of the way.

we're going to open this up in here. Yeah, the voltage is still just going kind of rampid over there. There's got to be some corrosion or something. This appears to be Factory tape though.

I Thought that's what it looks like. could be wrong sometime. The old black tape can hide a lot of sin. What the world? Because remember the the end of The Wire that we're hooked to this purple wire.

It should be completely open. Right now. it should be a completely open circuit. and right now I'm just trying to isolate exactly where I'm wiggling.

Move this whole harness frak me. Right now it's down to zero volts. Wait a minute. Wait a minute.

I might see some green. P Let me move. you guys. pull this whole stinking harness open all the way up Here in this wire is perfect.

You want to know what it is? It's this wire right here. So this this is our O2 heater wire. Kind of funny. See got to be an open in this too.

So this let me explain this. So this is our O2 heater. uh this is the one that somebody had already poked. It's green with white.

It has a bias voltage on it also. Okay so this has you know just for circuit. Integrity uh you know 12 volts or whatever is on this 5 volts. Uh we could probably check it and the little bit of corrosion on it or I should say not even really the corrosion but where somebody had poked this and the corrosion.

There's also an open in this purple wire because if I touch this wire our meter at zero and then if I touch this wire it goes off the chart goes above 5 volts. If I touch the wire here nothing slide my hand down me go Bango above 5 volts. Unbelievable! Let me get the meter here for you. I don't know if I can.

Hopefully we can hang this here somewhere so we can still still see see everything. I was going to say I'm filling with this wire and it's like spiking really high voltage and I'm like right down here again. so let me let me see if I can't get this set up where you guys can see it. hopefully I can get it where we can see everything.

So right now I'm touching the uh heater wire. Let's see you guys are just going to have to believe me at some point. Uh I'm touching the heater wire now I'm going to touch the signal wire and look at that. Let me put this.

uh, get it on a digital display. It'll be easier for you to see. Kind of a first for me. I Barely even seen that pin hole.

So uh, my hand's touching the heater wire. I'm touching the insulation on the signal wire. just the insulation Now, mind you. I'm not even touching the hole.

just the insulation insulation above it, insulation below it. Okay, I'm carrying 5 volts uh through the insulation of the wire. I'm not not touching anything bare. The only bare metal I'm touching is the bias voltage on the heater wire.

The heater is turned off currently. I'm touching the outer insulation above the connector now. I'm going to touch the insulation down here. Okay, we got what/? Qu Volt 2 volts 3 volts now.

I'm going to touch the bare spot and there we are. We've got 10, 10, and 1/ 12 volts. No kidding. jez uh.

long story short, it needs an auction since connector. Um, because it's carrying stray voltage through a light amount of corrosion through a pinhole prick that somebody put in it. uh, with a needle. And if I just take these two wires, let's just let's just touch the insulated portion of these two wires.

Uh, together. So this is the insulated wire. I'm literally touching two pieces of insulation together. Let's see.

Can you guys see that so insulated? This is not even the opens insulated insulated touching it together. and you can see down there. we're getting a quarter of a volt just through dirt dust. Uh, salt dust.

You know, going up the wires and migrating in that little tiny hole that somebody poked in it. So that gives you an idea. and then like if I touch the frame of the truck, we'll pull it the other way. Okay, so that's that's your problem lady, Somebody that was meddling.

So you got to be careful just poking a wire like that. You wouldn't think that voltage could go up through the insulation over top of the insulation like up up here. Like if I touch it up here. you know, not as well.

Let me get the Just Insulation insulation. So two non-conductive materials touching each other. Okay, I'll do it way up here just to kind of show you guys. Not too bad.

Bad there. We get closer to that opening, hold it there. Not too bad. The closer we get to it, you get at just the right spot where all the dust and everything lines up.

We might be wiping our fingers across it too much now. Yeah, it's starting to clean it up a little. but basically, uh, there's voltage being passed. No current, or almost a measurable amounts voltage being passed through the insulation.

because if we took like rubbing alcohol, we clean this all up. maybe even doing it with our fingers just wiping the salt dust off. It Probably not, because now our fingers are all covered with Shmo touching it together. there? Nothing.

Yeah, so our fingers still have, you know, some conductivity to it because we can touch this one and then touch this one and just through our body we're carrying. you know, a couple volts just hanging onto these two wires only on their insulated portions. Okay, I'm not touching any any poke hole not touching the bare metal. So that's why I was sending us on a wild goose chase.

I'm going to shut the camera off, flip at the bird and see if we can get us a connector. I Hope that makes sense to you guys what we've uh, what we've done. So think about this. your your oxygen sensor on these has four wires, you have a heater so that that accounts for two of the wires.

You got the essentially the heater ground and the heater power. and then we have a signal wire that goes to the Cm and then the signal ground we'll call it. So uh, you know, sensor high and sensor low. When we unplugged it out of the computer, we've seen that completely open.

which it should be. It should be just a piece of wire that goes from here to there. So we should have 0.00 volts in a perfect world. But we ended up having that 2 whatever.

it was 2.8 2.9 And that's when we knew that it was shorted to another circuit. There's you know, there's corrosion involves, there's something. but we also know that it's A. It was a short that can't carry currents, a short that can't light a light bulb.

It's a short that you know when we, uh, touch it with a test light, it goes to Z volts. So we knew right away that we're looking for corrosion. uh, or looking for some kind of connection there that doesn't allow it to carry current. You know, not a complete short.

We'll say so. and that was really interesting. and that's a really good uh. demonstration to show that it doesn't have to be.

you know this direct short Copper to Copper short. It can be carrying voltage across salt, across anything conductive across, you know, water. if this thing is wet or the customer's like oh, Every time I Go in the car wash, it does this. Um, depending on what circuit it is, some of these work on very very low current and just voltage.

we'll say I Know it's kind of oversimplifying it, but that's kind of how an O2 is as you saw on the other side. By just you know, licking our fingers and sticking them acrossair super high resistance. We can still pull the voltage down or using a, you know, a a Hi impedance meter I don't know what this one is. Probably 10,000 Mega ohms or whatever.

Uh, using a high impedance meter. Even just checking it with your meter takes it from 450 MTS down to 400. Uh, so that's that's some things to keep in mind. Uh, so that's it.

Long story short, it just needs a connector and the reason it has a problem is because somebody did the Hokey pokei. somebody put a hole in in those wires at some point, which is kind of peculiar because they're not green and um, to be honest with you, I was actually just going to, you know, throw some tape over the one and you know, ship it. Just given the overall condition of the truck. But that's it.

Hopefully it makes sense if it doesn't. Uh, leave a question. In the comment section, there's a ton of super smart people uh in the comment section that are oftentimes answering questions. Uh, and that's super helpful cuz there's really some you know, really intelligent people there and they always, you know, help me answer questions and stuff so questions, leave them down there.

Let's get some parts. he.