Help identifying wire disconnected by firewall, back of manifold.

2013 GMC Yukon XL 5.3L vortec

Hey y'all. I would really appreciate some help. I can't seem to identify this wire by the back of the manifold. It's part of a harness coming out by the firewall. I've included a picture.

Recent history of the situation : Yukon is throwing evap codes. I had it at a garage about a week and a half ago. The codes started after that along with a ticking noise that sounded like a lifter.
This particular garage is a ways away from where I am now, so I wasn't bringing it back. I started investigating the evap system. They left the hose coming from the purge valve disconnected in the back of the engine. I reconnected that. While I was back there I noticed this wire that was disconnected. I've looked at diagrams, I've been fishing around looking for the mail connecting piece. Can't find it. Any help would be appreciated, thanks in advance.

Eish12 said:

2013 GMC Yukon XL 5.3L vortec

Hey y'all. I would really appreciate some help. I can't seem to identify this wire by the back of the manifold. It's part of a harness coming out by the firewall. I've included a picture.

Recent history of the situation : Yukon is throwing evap codes. I had it at a garage about a week and a half ago. The codes started after that along with a ticking noise that sounded like a lifter.
This particular garage is a ways away from where I am now, so I wasn't bringing it back. I started investigating the evap system. They left the hose coming from the purge valve disconnected in the back of the engine. I reconnected that. While I was back there I noticed this wire that was disconnected. I've looked at diagrams, I've been fishing around looking for the mail connecting piece. Can't find it. Any help would be appreciated, thanks in advance.

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weird I personally can only guess it is supposed to be connected to something down lower, normally right there is where the oil pressure sensor is but that connector is a 3 pin
what kind of work did you have done? i wonder if that harness goes down under somewhere....
no check engine light?

vlom?

j91z28d1 said:

vlom?

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Looks like it might be that. Sus.

Looks like the VLOM connector
Do you have your afm/dod disabled ????

Doubeleive said:

weird I personally can only guess it is supposed to be connected to something down lower, normally right there is where the oil pressure sensor is but that connector is a 3 pin
what kind of work did you have done? i wonder if that harness goes down under somewhere....
no check engine light?

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At first I thought it plugged in next to the oil sensor, the clip looked like it had a spot for it, but it it doesn't fit next to it.

I cleared the two codes that were there. One was an evap code, the other is a catalyst system code p0420.
Now that I plugged that evap hose back in, the EVAP code did not come back, however, the catalyst system code did come back, p0420.

Yukon went in to the shop for them to put the deactivation solenoid in for the fuel management system couple weeks ago. Only for them to tell me that it didn't need it because it didn't fit. So they took the manifold apart to put the solenoid in, that never went in. I got the vehicle back with this situation.
I'd already used my Diablo scanner to deactivate the fuel management system, as it's a newer engine.

History:
I had a new engine dropped in just over a year ago. Same garage did a bit of a rush job, and with that they failed to program the fuel system, to deactivate the fuel management.
When I went back in and they realized they hadn't done it, they tried to pass it off on me by saying they told me that I was supposed to deactivate it. At the time I just assumed they did it, and they never mentioned it. So then they wanted me to purchase a deactivation solenoid. Which I did, as long as they did the work. Then they tell me the solenoid won't work.

yep goes on the vlom, I don't think that is the reason for your cat code though

Doubeleive said:

yep goes on the vlom, I don't think that is the reason for your cat code though
View attachment 451405

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That's it .. thanks!

j91z28d1 said:

vlom?

Click to expand...

Foggy said:

Looks like the VLOM connector
Do you have your afm/dod disabled ????

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I disabled the AFM with a Diablo scanner. It's the second engine in the Yukon. The scanner came with a crate engine, it was pre-programmed to disable the AFM.

Eish12 said:

That's it .. thanks!

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Yep, I agree that it's not likely to be the reason for the cat code