Hey viewers welcome back to the self made opportunity. That's a 2003 chevrolet, it's a tracker uh! It's got the big 2.5 in it. I believe, uh. This thing came in the other day with the money light on uh.

The guy has been frustrated with it and he's thrown a lot of parts at it and got it fixed from where it was whatever koji was having some problems with two sensors and then got down to this problem. Uh with this purge solenoid, so i checked it out for him. I told him that the pcm is bad, so i'm going to run you guys back through that it was a pretty quick, pretty easy test. Well, lo and behold he got us a used ecm.

I believe these things are plug and play so we shouldn't have any issue and just want to bring it along, so i've never cleared any of the codes out now. Evidently, these o2 heater codes, so he's got heater codes for all four o2 sensors. He i think he said that he replaced co2 sensors and then found the blown fuse. You can see the only two pending codes.

The two codes that keep coming back are for this perch control valve circuit open. That's because i left the connector unplugged and then this was the kodi who's combating here. The 445 perch control circuit short and that's one we're going to kind of focus on these were all in it. Last time uh.

He came all these stored codes here, we're going to kind of disregard some of those right now we're going to go to this evap purge control and i'm going to show you what's going on so grab a test light here. So the uh canister purge valve is right here. So this is your uh, your purge solenoid that pulls the fuel vapors out of tank, and typically they have a power and a control. So we got a test light hooked to a battery negative here.

One of these is the power wire, so this one is the power wire and then this wire here comes from uh comes from the pcm and when it wants to turn this purge solenoid on it, it duty cycles, it turns it on or off or it can Even hold it, you know full open, so we have power and then we'll check the ground side of it. I'll just grab a t-pin here and technically right now you know kion engine off this should this circuit should be turned off, should not light a test light because it is not being turned on oops. I'm going to get this on here. If i could just move down the battery and you'll see right now that that test light lights up thin, it doesn't light up as bright as you know, as when we're uh, you know going from battery negative battery positive, but you can see 100 billion tesla.

This thing lights up thin and just as the code states, that would indicate a shortened circuit. So now the problem is, you know: is this wire actually shorted to something another circuit, perhaps shorted to ground uh or is it internal in the pcm, and that was pretty easy to figure out? I went inside the car unplug, the pcm. The light went out. Well, that doesn't mean a whole lot, so i took and just stuck power on this wire individually, and you know that was that the wire is perfectly intact and it is not short of the ground.

So therefore it's the pcm and the other thing i did that. Actually goes to pin one of the pcm i just with pcm unhooked. I went to battery positive touch that pin by itself, and it lit up dimly also telling me internally that pcm is shorted, so that was a pretty quick and easy diag. I also believe that this is the cause of the rich coat.

These got rich for both banks, because i discovered that when the pcm does command this because that transistor, the pcm still has control, and it can turn it on when it turns it on and opens it, it stays open. It cannot go close until the key is shut off, so i believe, that's also given him his rich codes uh. What we need to do now or what we can do is we can verify that the o2 heater circuit is still working, so we got our tesla here. Two heater relay is right over here.

If you guys can see that i'll move you, i did check this last time he was in and that's when he told me so we're gon na look to see if we have power. So we have power coming out of both sides of this relay. So that tells me that his o2 heater fuse is good. The o2 heater circuit is still good.

One of these should have power two yep, so we have power on three three legs, one on the control side and both load side. So that tells me that it has not blown a few since he put it in it's been several weeks and likely whatever his issue with the o2 sensors and the heater circuits has been resolved right up under the passenger dash. Here we have the pcm, so hopefully that all makes sense you guys, as far as where i'm at i hate redoing videos, i should have just recorded it the first time it came in, but it's a pretty quick, easy diag um, i kind of wish. I knew what originally happened with his o2 sensors but, like i say he had already sorted that out himself, you know sounds like one of the heaters was shorted blowing the fuse and he just replaced them all.

So i think what we'll do uh before we even take the old one out of the bracket, we'll make sure we're not going to have any issues with the new one here. The used one so keys off right now. Everything unplugged, because this car should not have any security and it's old enough, where the vin number doesn't really matter when it comes to state inspections and such so we'll see if we can't just plug this in okay, let's see if this one first thing. First, all right, no lights.

The key on now we're going to reread the code to this pcm. We should have the 444 for sure, but that short circuit code should be gone. Of course, i don't know if there's any other code stored in this from the other vehicle, but oh there we go. Oh look at that 444.

So that's 100 verified. We should be able to go back in here with the test light. You guys should be able to see that now. Hopefully, we should have a power still obviously uh, look at the tesla that works here, so we should still have a power but so power, but on this side we should it should not light a light when we go back to ground or back to battery positive And it does not so we're on battery positive right now, so anything that we touch that's a ground will light up our light and if you remember that control wire was shorted before and now it's not so that's good.

Now i have already checked this purge solenoid to make sure it is not shorted and as a precaution, he got a different one to put on there in case it was intermittently shorting. You know what i'm saying, because once once you find a circuit, that's bad. Let's say you know: okay, so this thing's burned up the transistor whatever's in the pcm that switches it on. That gives you a little pause.

You're like well, you know what what smoked it um, you know. Was it this purge, solenoid, shorting out and uh. You know caused an overcurrent on that circuit and the original one tested the same as the replacement. I think it was 30 some ohms, so it doesn't draw a ton of current.

However, some solenoid type solenoids can go bad when they're, hot or cold. You know be, you know, as they get hotter. Resistance goes down almost under shorts and the pcm tries to turn it on and poof up in smoke, so just pull the little guy outside now. What i want to monitor, i'm going to take it for a drive.

We're going to look at the purge command and then, as it warms up here. Well, it's it's already warmed up because the guy just drove it here, but um we're in close loop now and i want to see the fuel trims make darn sure. It's definitely not really running rich. I don't think we're going to get any of the monitors to run, but i'm going to drive it make sure the perch is being commanded, make sure we're not setting any pending codes and then we're going to call it good.

I mean i'm very confident in the in the diag in this one. It's pretty cut and dry, so shouldn't be a problem just glancing over at scanda cruising down the road fuel trims, look fantastic, actually we'll! Let the long term get populated here, because we did reset the pcm and then hopefully it decides to pull a purge excited to pull over here. For a minute i pop back into generic obd2 and our fuel trims look great after driving, i'm you know completely satisfied with our short terms and long terms on both banks uh, the purge cylinder was working there. When we were cruising, i could see it pulling vacuum in the tank, we'll make sure we didn't say any pending codes, we'll check and see how many of the monitors set.

So no codes detected, and hopefully it ran a couple of the monitors. Oh well. I ran most of them. Actually, so six of them are complete.

Two of them are incomplete. No engine light no codes success. I kind of wish i brought you guys, along on the on the first time the guy brought this thing in a few weeks ago. I wasn't really sure where it was going to head or if he was going to come back with a you know, use pcm to finish it.

I know you guys like closure uh, but all in all it was relatively easy, and hopefully you guys can learn something from this. You know when you get those circuit codes and you identify it like you know. This wire is definitely short at the ground where, in the box you know or the controller, whatever controls it shorter to another circuit. You got to isolate that then just make the call.

Unfortunately, this thing's pretty old, like i said they, don't even store the vin in these pcm. So these things are plug and play no security, rock and roll baby uh. Why don't you guys rock and roll into that comment? Section questions comments, concerns put them down there. The instinct, the facebook, the wipers just remember, viewers, if i can do it, you can do it thanks for watching.