P0351-0353-0355-0357 coil pack problem

[08z71bgm]

So before we go down this road. I’ve swapped the whole bracket packs and harness for another and code is still there.

My question is where are the grounds for this bank of coil packs off the main harness? Is it behind the cylinder head?

I have a feeling the ground broke off somewhere and is shutting down the whole bank of coil packs. Just don’t know where it is.

 

[Fless]

It might be more efficient to verify which circuit (ground or power, control) is missing. That will let you focus your diagnostics. When you test the input to the harness, what do you get?

 

[Doubeleive]

So before we go down this road. I’ve swapped the whole bracket packs and harness for another and code is still there.

My question is where are the grounds for this bank of coil packs off the main harness? Is it behind the cylinder head?

I have a feeling the ground broke off somewhere and is shutting down the whole bank of coil packs. Just don’t know where it is.

just ground that side to the frame
that will get you running in the meantime till you hunt down the break

 

[Doubeleive]

the upfitter guide may show it or maybe @swathdiver has the diagram handy

 

[08z71bgm]

Checked all the fuses. Voltage. What’s odd is nothing showing OL. So why is the whole bank dead?

Engine runs without a main harness attached to the coil pack harness the same as if it was plug in. Makes no difference.

 

[08z71bgm]

Upfitter doesn’t show the ground locations

 

[08z71bgm]

It was definitely ground. Jumped it out and grounded it.

And still no one knows where the factory ground stud is for it? Which was my original question still not answered!

 

[Fless]

I'm sure that AlldataDIY would have the wiring diagrams for your truck.

So you had ground at the harness connector when you tested before? Weird.

 

[08z71bgm]

Yup. I have tons of spares and I spliced one out and ground it to the firewall and boom idles smooth. Which was my whole huntch from the getgo.

 

[08z71bgm]

No one has digital service manual here? Hard to believe. You guys should upload and sticky these docs for people.