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Discussion Starter #1
currently working on a 2002 f250 with a 7.3 in it. customer was driving down the road and truck shut off and will not start since, crank but no start. has edge evolution installed in it and chip says pcm not responding, so unplugged that and hooked up scan tool and still no pcm connection. so made sure there was power to the pcm and also checked ground had both, fuses and relays are all good as well. so we checked idm and that checked out as well. just for fun we tried different pcm and idm off of another truck still no start but our pcm and idm ran the other pickup just fine. so we have been chasing wires all day to see if we could find short or anything of that nature and nothing came up there either.... a bit lost on what to look for now
 

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Fixing Broken Stuff
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No communication with the PCM usually = the PCM has no power. Does the data link have power? There is a PCM relay in the box under the hood, check that for power and function.
 

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Discussion Starter #3
Yes it has power at data link and checked all the fuses and relays and those are all good as well
 

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Make sure there's continuty (sp) between obd port and pcm on data line.
 

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Fixing Broken Stuff
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Ok, you swapped your PCM and IDM and you now that stuff is good,
Do you know for sure which relay is for the PCM? and you swapped it?
Are there any dead fuses in the fuse boxes?
See if you have any dead wires on the ignition switch. with the key on I think all of them should be hot, no grounds go though it.
What codes do you get?
Maybe try I different scanner and pull the tuner off the truck
 

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Discussion Starter #6
I have tried using two scan tools and I get the same response that it cannot connect with the PCM so I can't access any codes and because I can't connect with the PCM it also will not let me uninstall the tuner. Going to check the ignition switch power again just to be sure. As far as the fuses there are no dead fuses at all in the fuse box and tried two brand new relays. We also tried new fuses for the fuses that control PCM power because we heard sometimes they will show power across the fuse sometime but they have to high of resistance and don't let high enough voltage go to the PCM but that didn't help the problem either.
 

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Fixing Broken Stuff
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Ok, you must have a open circuit/broken wire somewhere, your going to need a wiring diagram, then and start checking each wire starting from the data link. That's what I would try.
 

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Rustbucket
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This might help
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Fixing Broken Stuff
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^^^^ Yep that should do it, I'd start with checking the wire between the data link and PCM.
 

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currently working on a 2002 f250 with a 7.3 in it. customer was driving down the road and truck shut off and will not start since, crank but no start. has edge evolution installed in it and chip says pcm not responding, so unplugged that and hooked up scan tool and still no pcm connection. so made sure there was power to the pcm and also checked ground had both, fuses and relays are all good as well. so we checked idm and that checked out as well. just for fun we tried different pcm and idm off of another truck still no start but our pcm and idm ran the other pickup just fine. so we have been chasing wires all day to see if we could find short or anything of that nature and nothing came up there either.... a bit lost on what to look for now
Was there ever a solution to this issue I have the same problem occurring right now. I am lost. Thanks in advance
 

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It is a common problem to have fuel bowl heater short and blow the fuse, which is the same one that supplies power to the pcm. If no wait to start light then check the fuse. I think it's the #30. You can unplug the fuel bowl heater and run without out it.


Sent from my iPhone using Tapatalk
 

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BigRed02
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Is a bad fuse block a possibility? I think there is 2 circuits for the PCM, right?
 

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I have a similar issue with mone. I have no power to the fuel pump no communication with my pcm. No bad fuses or relays on my mine. See if you have any of the same issues
 

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I have been fighting the same (or very similar issue) hope someone here can help out.

Truck ('02 Excursion 7.3) dies with no warning. Cranks with no start afterward. Passive anti-theft light flashes fast, then goes to the 1-6 code which is no communication with the pcm.

First time it happened unfortunately I was 2 hours from home and had to have it towed to nearest ford dealer. Their only fix was to replace the PCM. 6 weeks later i pick it up and drive it home. After about 3-4 hours trouble free driving same issue repeats.

This time I have it towed to a local diesel shop that specialized in powerstrokes. They find no power to the PCM, and diagnose the fuse block as bad. Replace, pay $900 and I am on my way confident that root cause was found.

Drive another 2 days and same problem repeats. It is now back at the same diesel shop.

Any thought from the forum?
 

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I am having the same problem with my 2001 F350 7.3 it just died on me will not start, wait to start light does not come on and I hooked 3 different code readers to it and all said negative or no response from PCM, I checked all fuses and relays and everything is good I'm getting power to the OBD2 port but no response from the ECU the truck will run if you spray ether but when you quit spraying it it will die it's like the computer is not telling the injectors to fire can somebody please please please help me with this I don't know what it would be my email is [email protected] if anybody has found the solution for this problem please email me
 

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I had this happen on my 2000.

Somehow the EBV sensor spazzed out, it was suggested to me to try unplugging it and sure enough PCM back online and could read the truck to see nothing else was up.

Something to consider, I can't remember which member told me to try it or I would credit them :{
 

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Kennedy
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Since this post thread got started back up I will throw another possibility. Previous owner had a aftermarket stereo in mine and I was messing with the battery. I then had the same problem with no response from PCM.

It was because I disconnected the ground from my PCM that was to my drivers side battery.
 

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Im having this problem with a 2002 I just bought at an insurance auction, it was hit at LF fender. Not able to connect to a code reader, no power at the IPR, fuel pump, or inertia switch. Anybody come up with a solution to their problem???
 
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