2009 6.0 Hybrid. Electrical issues!

[GHost0]

Hey guys! I just recently bought this hybrid Yukon and have been working through the issues, it’s been a fun project, and when I got it, it had half a dozen error codes, I’m down to two, no matter what I do I can’t seem to find the Solution and I’ve been beating my head against the wall for two weeks now..

I have upgraded my grounds


I have some absolutely weird electronics that are all not working in conjunction... Rear lift gate, windshield wipers, to name a few, etc.

I bought a short circuit tester a few days ago, I believe I definitely have a short circuit somewhere, it does say I do, but I also know those machines can sometimes suck..

I probed for electricity at the rear hatch but got nothing, nothing at the rear hatch fuse under the hood either, this is the same for about 10% of the fuses in the fuse box..

Now I understand the chance of all of these components failing at the same time is slim to none...

I’m beating my head against the wall trying to figure out what is going on here..

Also,

I am getting P0522 (Oil pressure) but I just replaced the sensor.
I am also getting P0108 for MAP (which I’ve also replaced)
I’ve gotten the “oil pressure low turn of engine” message still, BUT the engine oil pressure looks just fine..
I’ve already replaced my evap system, which got rid of those errors.
The oil is all brand new.

Has anybody seen anything like this by any chance...

 

[CaptainAmerica1]

BCM is where I’d start

 

[GHost0]

BCM is where I’d start

Thanks! Do you know if they are all interchangeable? Or if there is a way to test?

 

[BG1988]

Thanks! Do you know if they are all interchangeable? Or if there is a way to test?

no they are not it's specific P0108 says an open ground
What is an open ground? An open ground is when you have a receptacle that is not connected to an equipment grounding conductor

disconnect the 12v+ battery (both posts)

DO NOT manually ground the map sensor,( this can cause a surge of power to that ground point and may damage wires etc...) find the open ground and fix it

Check the ground wire behind the inverter box and engine grounds
first one is near cylinder 1(drivers side) and the other is in the back


it's chain linked check the one going to the engine block and then from the engine to the chassis there is another one connected from the chassis to the inverter hidden behind the inverter


also another one to check is near the radiator support i think it's on the drivers side

there is also a few ground wires on the frame rail drivers side

 

[GHost0]

no they are not it's specific P0108 says an open ground
What is an open ground? An open ground is when you have a receptacle that is not connected to an equipment grounding conductor

disconnect the 12v+ battery (both posts)

DO NOT manually ground the map sensor,( this can cause a surge of power to that ground point and may damage wires etc...) find the open ground and fix it

Check the ground wire behind the inverter box and engine grounds
first one is near cylinder 1(drivers side) and the other is in the back


it's chain linked check the one going to the engine block and then from the engine to the chassis there is another one connected from the chassis to the inverter hidden behind the inverter


also another one to check is near the radiator support i think it's on the drivers side

there is also a few ground wires on the frame rail drivers side

Thank you very much BG1988.

I have the battery fully disconnected. MAP sensor is not manually grounded. The ground wire behind the inverter box is snug and still flexible still. The ground wire near cyl 1 is there but was showing a poor connection earlier. I have since run a secondary ground connection frame to block and the connection is perfect there.

I've run a voltmeter over the ground connections I've seen so far and have a solid connection.


Im not sure if this is going to help or not, but I just purchased a "short detector". I believe it is showing a short to ground on one of the three power cables, but nothing looks frayed or damaged at all. When I run the wireless detector, there are like a dozen different fuses that all show as being shorted. I am also not getting any power to those same fuses normally when plugged in.

I'm going to hop under the truck again and see if I can see anything, but so far, all of my grounds appear and test to be in good shape.

I'm missing something somewhere...

 

[BG1988]

Thank you very much BG1988.

I have the battery fully disconnected. MAP sensor is not manually grounded. The ground wire behind the inverter box is snug and still flexible still. The ground wire near cyl 1 is there but was showing a poor connection earlier. I have since run a secondary ground connection frame to block and the connection is perfect there.

I've run a voltmeter over the ground connections I've seen so far and have a solid connection.


Im not sure if this is going to help or not, but I just purchased a "short detector". I believe it is showing a short to ground on one of the three power cables, but nothing looks frayed or damaged at all. When I run the wireless detector, there are like a dozen different fuses that all show as being shorted. I am also not getting any power to those same fuses normally when plugged in.

I'm going to hop under the truck again and see if I can see anything, but so far, all of my grounds appear and test to be in good shape.

I'm missing something somewhere...

check the positive connector on the lower fuse box looks like it would be easy for it to ground out....

 

[GHost0]

check the positive connector on the lower fuse box looks like it would be easy for it to ground out....

Thats in good shape. I've attached a photo of where I am currently at, and what Ive had to disconnect to just have the wire short light turn off.

Im looking through wire looms at this point, but everything is looking good and clean..

 

[GHost0]

BCM is where I’d start

I just removed my BCM entirely, I am still getting the red light for a short.. Still possible its the BCM?

 

[swathdiver]

Hey guys! I just recently bought this hybrid Yukon and have been working through the issues, it’s been a fun project, and when I got it, it had half a dozen error codes, I’m down to two, no matter what I do I can’t seem to find the Solution and I’ve been beating my head against the wall for two weeks now..

I have upgraded my grounds


I have some absolutely weird electronics that are all not working in conjunction... Rear lift gate, windshield wipers, to name a few, etc.

I bought a short circuit tester a few days ago, I believe I definitely have a short circuit somewhere, it does say I do, but I also know those machines can sometimes suck..

I probed for electricity at the rear hatch but got nothing, nothing at the rear hatch fuse under the hood either, this is the same for about 10% of the fuses in the fuse box..

Now I understand the chance of all of these components failing at the same time is slim to none...

I’m beating my head against the wall trying to figure out what is going on here..

Also,

I am getting P0522 (Oil pressure) but I just replaced the sensor.
I am also getting P0108 for MAP (which I’ve also replaced)
I’ve gotten the “oil pressure low turn of engine” message still, BUT the engine oil pressure looks just fine..
I’ve already replaced my evap system, which got rid of those errors.
The oil is all brand new.

Has anybody seen anything like this by any chance...

You really need a Tech-2 and the online shop manual to work on this efficiently. Your issues seem to point to a bad BCM but a bad cell in the battery (not the big one) can also cause these kinds of gremlins.

 

[CaptainAmerica1]

If you’re near dfw I’ve got a tech2 and could help….