2004.5 6.0 Good fuel pressure and ficm volts. All fuses good. No prior problem.
Started truck in cold and snow, it started rough so I let it warm up to a strong idle. Tried to drive but no power and engine light turned on. Tried to scan but no communication but can talk to ABS and SRS. Once warm engine sounds good with throttle response, but in gear has almost no power or rpm in gear. I disconnected the egr and other sensors but still no com. The DLC test out ok but between 6 and 14 I do not have 60 ohm like the book I'm using says it should, it measures 1M ohm+. For the first time in decades I'm unable to fix my own truck, old age is not for sissys, if I could just read the codes and live data I could probably fix it. Please help if you got an idea, thanks.

 

You might want to look at this thread. The OP is dealing with similar issues.
https://www.ford-trucks.com/forums/1...t-the-dlc.html

 

For sure testing in the correct pin locations -- 6 and 14 ?
Those wires go straight to the PCM
.
.

 

Tried getting codes by key. Many different things that happened. Dlc on key is d262? Not able to get any more codes. Turned key and truck started normally with no cel. Tried to drive it and it drives! Afraid to actually take it anywhere I turned key off and restarted and cel came back on but not yet derated. Engine sounds fine, fuel pressure 51lbs. Tried the key trick again hoping to turn cel off but no luck. Still have no comm to pcm.

 

I'm thinking that leaving the batteries disconnected was why my cel turned off temporarily. Wish I could get more codes off the key and that I understood all the info it was telling me. The resistance test for 6 and 14 is not in my book and forgot where I got it. My book says check for ground at 6 and 14 if over 10,000 ohms, and I do, to check voltage key on, and is 2.5 to 3.5 for both and then the book ask if I have ANY volts and I do. Next step is repair circuit WTF? If I could read ALL the codes I could probably fix this myself.

 

That means time to get the DMM out and trace wires and look for any damage. One other step is to unplug
modules and see if the issue clears. Then if all else fails start replacing parts.

 

Ok, part of my problem is too much info out there not specific to my truck. There was a lot of info by pressing the trip meter and turning the key on. Is there anyway to read more than one code off the key? It seemed to show some live data as well. No mention of key diagnostic mode anywhere to be found so far.

 

Pin 14 is CAN High -- should be slightly higher than pin 6
Pin 6 is CAN Low -- should be slightly lower than pin 14
both together should be about 5.0 volts on an normal system

The 60ohm reading should be from pins 6 - 14
that is the buss terminators -- 120 ohms each, when combined equal 60
one terminator is in the PCM, I am unclear if the other is in the instrument cluster or ABS module

PCM, ABS, Inst, and TBC are on the main buss -- so if you are getting no ohms across pins 6-14, then the voltage is coming from one of the other connected modules -- that to not contain a terminator
that means at least one of the buss wires to the PCM is broken

Reference this thread for some info on the CAN buss system
https://www.ford-trucks.com/forums/1...-no-start.html

 

Just what are you using as a scan tool?

 

Thanks, I knew I saw a resistance test for 6 and 14. Im getting 1m+ ohms key off. Thanks for the help. I have things under my dash that are not shown in my book. I have unplugged almost everything, not sure about all the modules. I would think that I have created many codes yet my truck started on one crank and warmed up without a CEL. CEL does not turn on until I start to drive. Engine does not seem to be derated now and pulled a small grade at idle. Totally not going to drive it till I can comm with the PCM. Truck is in good condition but there is some small wire damage under the hood from repairs, critters and years, just like me...
Thanks for staying with me. This all happened after a long park in the snow, no problems or check engine lights since the egr and cooler was replaced 60k miles and many years ago. It totally surprised me when it instantly started this morning and warmed up. Accelerator did not respond at first but came to life as the truck warmed up. There was a lot of info on the key diagnostic test that I couldnt understand. I am going to remove the air filter again and look for more damage on the harness. If I could communicate with the truck I believe I could fix it. Having some problem posting my text. 2 kind of long messages I wrote to you did not post. Operator error I'm sure. Im using an Innova that I used yesterday to scan and clear codes on a friends truck, his tester will not comm to my truck either. Thanks again.

 

The pinouts on the PCM are different for 2004 and 2005 models, not sure which one yours is

the CAN buss -- pcm body connector
on 2004 is 32 and 44
on 2005 it is 13 and 14

you would need to ohm the wires to the data port to confirm

 

I am going to try and see if I can find some pinpoint testing that covers the networks in your 2004 1/2 6.0L.

 

The truck seems to be more like an 05 than an early 04. My book does not cover the throttle body on the front of the engine. Im going in to check harness tomorrow but am suspecting throttle related parts as well.

 

Here is the VSM location.

Also the Vref is used for the throttle. So you should watch the Vref voltage because if it drops out you will loose the throttle.
One place that is very prone to cause the Vref to drop is the EBP sensor. Take a close look at the connector and look for any
damage to the wires. I had issues with one of my trucks and found the damage by looking the connector over with a 10X
magnifying glass. I was able to repair the connector and fix the issue.

 

Sorry for off topic, but there is a 6.4 door mod in the above video: