All of the sudden my 2004 6.0 Excursion has a no crank no start, I noticed it isnt reading my tuner and or scan gauge. I took it to the diesel shop and he swapped the pcm and it fired up. Switched it back and it pull the fan clutch and sent the pcm into safe mode. Put a new Fan Clutch in fired it up and it all seemed normal. Took it for a test drive and it shut off again, when it shuts off, no fuel pump, no gauges, no tuner, just does nothing. Switched the pcm again and it fired up we test drove it and it seemed ok but still didnt feel rite. Am i headed in the rite direction with maybe a new pcm? Just want to make sure because there like $500.

Please help

 

Inspect the harness. If the reference 5v is shorted it can cause issues like this. With the original PCM in, start it and monitor reference volts.
Can the garage put your PCM in another test truck and see how it acts?

 

Thats a great idea I will ask him, I will keep you posted.

 

After swapping out the pcm the truck would continue to shut off and pull all sorts of codes. We finaly decied to pull the wire loom back off of the wires for the Fan Clutch and noticed that they were all fried. The first code was the fan clutch, so im thinking that must of been the cause. Needless to say I am having to buy a new harness, this has to fix the problem.

 

Thanks for the follow up.

 

Did this end up fixing it?

 

It's been almost 5.5 years and he hasn't been back so I could only imagine it did in his case.
. If you have an issue that even slightly varies, post up and create your own thread.

 

He started a thread, but I think he would have better luck here like you suggested. Hopefully he starts one in this "sub forum".

Here is his thread:
https://www.ford-trucks.com/forums/1...l#post20228629