2004 F550 PCM Problems
 

First off I bought this truck not running, the ficm was missing the engine and fi wiring harnesses were burned. Replaced both harnesses with ones from an 06, installed ficm. Tried to start, would not crank no ground to the starter relay. Pulled the Pcm from my 05 plugged it in and fired right off. Truck will run and idle with the 05 pcm but no throttle. Ordered 04 pcm installed again no crank injectors don't fire. Tried to reprogram the new pcm would not read. Sent it back received 2nd pcm guaranteed "good" this time. installed same no crank no injectors, took it to ford today to try programing this one still no luck will not read the pcm will not take the program. My question is what is the difference in the 04 and the 06 harnesses and is this my problem and not the Pcms? Also where can i find wiring diagrams for the engine harness? Thanks

I believe the harnesses are the same, the PCm on fenderwell and the FICM that sits on top of drivers side valve cover are all interchangeable from 03-07. Make sure the ground on the injector harnessis hooked up, it hooks up on top-back valve cover bolt. make sure the electric connections to the ICP and IPR are in good shape. Whre is the ICP located on this truck? pass side valve cover or behind turbo?

Reminds me of this:

ecm issues.. riddle me this boys and girls - PowerStrokeArmy

Thats it exactly
 

My truck dose exactly the same thing. I was thing of trying a new throttle petal next. But sounds like a wiring problem instead. Is there a diagram showing which pins should have ground to the Pcm?

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Harnesses are not the same the 04 has wiring for the egr throttle actuator and the egr throttle position sensor which are not on the 05 and up. ICP is on the valve cover, all connections are good.

You can just leave those connections unplugged, a lot of guys with the 04's that have the throttle plate just remove it, put an 05+ intake elbow on and just leave that unplugged.

New pedal isn't going to help you. Someone else here just had that problem too I believe. Definitely sounds like a ground issue.

I'll see what I can find for wiring diagrams. Bob probably has one.

Powerstroke 6.0L Technical Intro Manual
Thats the best I can do for you.
You can leave the butterfly connections off, it doesn't hurt a thing, my truck doesn't even have the connector on the wires anymore, it was cut off by a pulley:w2:, and yes the early 04 has the ICP on the back but a later 04 harness would work fine.

wiring
 

I found the wiring digram I think it's page 60 in the 04 manual update. Haven't had time to check anything yet. My wife things remodeling the house is more important. :td:

Update
 

I found the wiring issue with the ground. repaired that still dead with my 04 pcm but now when I put in the 05 pcm it runs and the throttle works. Took it to ford to day to try reprogramming again now the wiring is good, but still no luck no com with pcm. So now I guess I need to find a pcm any ideals?

Junkyard is probably your best bet. Don't see PCM's popping up for sale too much. Try checking one of the big Ford forums though, a lot more Ford specific stuff for sale there. :c:

Tons of them on ebay, for decent prices.