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6.0 Wiring Harness Issue

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4.8K views 25 replies 4 participants last post by  MtnTallPaul  
#1 ·
hello. i have a 2005 6.0 Lariat Powerstroke & i can move my wiring harness while the truck is running & it misfires & runs rough. i can be driving down the road & go to get on the truck a little & the wrench light & the check engine light come on & it starts to run rough & misfire but then i go to turn it off & it it back on & it’s perfectly fine, all codes & lights are gone. does anyone know the part number for the ficm wiring harness? i already have the engine wiring harness. thank you for your time
 
#3 · (Edited)
The Livewire is a poor code reader (it does not retrieve all of them). Great for PIDs, but not so great for codes, ie not thorough.

Every 6.0L owner needs a good scan tool that reads codes. ForScan is the best value, then Torque Pro.

Since you could read an ICP code, posting the code number itself is the best thing to do. Anyone that knows their "stuff' on the 6.0L will know what every code number means.

A bad ICP will not cause a wrench light. Also, you may not even have a bad ICP because if you try to start with the ICP unplugged it will throw a code without anything actually being wrong.

You could have a bad FICM, or the FICM plugs might not be firmly installed, etc.

If you are just dead set on spending money on an injector harness, the '05 injector harness is 5C3Z-9D930-A
 
#5 ·
The Livewire is a poor code reader (it does not retrieve all of them). Great for PIDs, but not so great for codes, ie not thorough.

Every 6.0L owner needs a good scan tool that reads codes. ForScan is the best value, then Torque Pro.

Since you could read an ICP code, posting the code number itself is the best thing to do. Anyone that knows their "stuff' on the 6.0L will know what every code number means.

A bad ICP will not cause a wrench light. Also, you may not even have a bad ICP because if you try to start with the ICP unplugged it will throw a code without anything actually being wrong.

You could have a bad FICM, or the FICM plugs might not be firmly installed, etc.

If you are just dead set on spending money on an injector harness, the '05 harness is 5C3Z-9D930-A
okay thank you for your time! isn’t the engine wiring harness for the 6.0 5C3Z12A581H or what would that part number be if that isn’t the right one?
 
#4 ·
I would try and pinpoint the exact location where you can wiggle the harness & make it misfire, and then open up the harness to inspect the wiring. You can probably find the issue and fix it, rather than just spend the $$ for a new harness. Problem solved & money saved = WIN/WIN!

-jokester
 
#7 ·
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#12 · (Edited)
I do not know the date or serial number cutoff between old and new '05 harnesses. Just couldn't find it. I do know that most of the changes were made simply to reduce chafe points and provide more secure connections.

Also, the VGT connector was specifically changed (improved).


EDIT (just had to think a bit more):

Also, some '05's had a MAF sensor, and some didn't (the early ones didn't). So check for whether or not you have a MAF sensor. That MIGHT be an identifier between early and late!


IMO either harness would PROBABLY work, but the later one is the better one. If you have a MAF sensor, you really need a MAF sensor plug in the harness. I just don't recall if the early harness eliminated that plug or not - I seem to recall that the plug itself was not actually eliminated for the early harness (ie people have reported having that plug just hanging down and "capped").

EDIT again - The MAF was deleted in the mid 05 production (in Nov 2004), and added back in late 05, after February (estimated) of 2005. So the earliest '05's and the latest '05's have a MAF sensor! With that information, I do not think the harness change involved the MAF sensor "back-and-forth".
 
#15 ·
Early 05's with the IAT1 sensor in the air intake still have the MAF connector. It just dangles off to the side alone, hanging out like a nerd at a frat party... 🤣

-jokester
 
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#16 ·
I do not know the date or serial number cutoff between old and new '05 harnesses. Just couldn't find it. I do know that most of the changes were made simply to reduce chafe points and provide more secure connections.

Also, the VGT connector was specifically changed (improved).


EDIT (just had to think a bit more):

Also, some '05's had a MAF sensor, and some didn't (the early ones didn't). So check for whether or not you have a MAF sensor. That MIGHT be an identifier between early and late!


IMO either harness would PROBABLY work, but the later one is the better one. If you have a MAF sensor, you really need a MAF sensor plug in the harness. I just don't recall if the early harness eliminated that plug or not - I seem to recall that the plug itself was not actually eliminated for the early harness (ie people have reported having that plug just hanging down and "capped").

EDIT again - The MAF was deleted in the mid 05 production (in Nov 2004), and added back in late 05, after February (estimated) of 2005. So the earliest '05's and the latest '05's have a MAF sensor! With that information, I do not think the harness change involved the MAF sensor "back-and-forth".
FWIW, here is what is probably the MAF sensor connector on my truck, which has no MAF sensor.

Image
 
#18 ·
So you probably have an early 05.

Do you have a connector as pictured in my photo above?

Is it capped off, or plugged into a sensor?

In any case, the post from @bismic above seems to indicate either early or late 05 should work for you.