So my 6.7 left me hanging the other day, went to start nothing. Towed it into town started. Went to start it couple days later nothing. Jump the plug by right battery starter turns. When key is turned to run no glow plug light, no fuel pump prime. Tested ignition switch good. Tried 2 new Batteries nothing. got power on fuse 52, continuity from fuse 52 to pcm connector. Fuse 49 and 50 also have power. Took all 3 connectors at pcm out and blowed air through and sprayed W.D nothing. Even tried with connector on transmission. Scan tool will not communicate with pcm.
Codes after cleared:
instrument cluster
uo100 lost communication to pcm
u300a-64 ignition switch...
transmission:
u0294 lost communication with pcm
Body control module:
u0100-87 lost communication with pcm
B10f1-14 key in switch short to ground or open

 

Have you tried re-seating the PCM connectors under the hood? Maybe remove them, spray with WD40 and re-seat.

 

Do you use the parking brake often? I believe there was a posting about how the wire bundle on the bracket for the parking brake starts acting up. There is a posting about it. Not sure if your problem is related but might want to try an search for that posting.

2005 Ford F250 Crew Cab 5.4l 3 valve

 

Try this link.

https://www.ford-trucks.com/forums/1...ont-start.html

2005 Ford F250 Crew Cab 5.4l 3 valve

 

Thanks guys. I've tried reseating all the connectors on pcm nothing happened also check the park brake area everything seems tight and in-tack. Ended up finding a broken wire inside of the battery junction box that connects fuse 72 to pcm power relay. repaired the break and started up no problem

 

Thanks for the update.

 

will have to keep that in mine. Thanks for the report.

 

Last year my truck got struck by lightning. It would start but shut off immediately.
a week at a dealership in Florida and $3500.00 later it was good to go.
They replaced three of six "computers". The tech said he was talking to Ford all week to get the right boards replaced. Insurance did cover this. Glad yours wasn't this problem.

How would that wire get broken?

 

 

 

Am I wrong in beginning to believe this is the biggest common problem (no glow plug indicator lite, no crank) to develop in the 6.7? I notice it because last year I had the same problem with my 2014 6.7. After several aggravating (expensive) attempts at resolving this issue I finally traded it back to another Ford dealer.

I do hope this problem has been addressed/ corrected in my 2018; if not I will be off to the Chevy dealer next time. For me it doesn't matter if its warrantied or not, its the aggravation/ fear of being stranded out of town with a fifth attached.

Note: my local Chevy dealer currently has several very Sexy dually's on his lot. I need a cold shower.

 

Can anybody go into more detail on this repair? Picture of the wire that was repaired. It seems like a very similar problem I am having

 

Mine was a bcm connector for ignition switch with pins that were enlarged causing poor connection. Ford installed new connector and pigtail

 

could you give more detail as to where this connector can be found?

 

2011 F250 6.7 King Ranch, 348k km

So I had this same problem happen to me suddenly. Parked my truck after towing for a few days, went to start it a week later and I couldn't ( all -----.- on the odometer, lots of warning chimes, no crank or start, no PCM communication.)

process:
- Batteries charged and charge hooked up to keep voltage up for tests
- I checked out my OBD connector, proper 60 ohm reading on high and low speed bus, voltages good
- I ran forscan, and I could contact all the modules except PCM.
- looked under the dash, did the wiggle / reconnect of the cable down in the driver's side, unfortunately I wasn't that lucky
- Fuses 33, 34, 36, 37 (PCM related) all showed only 35mV - not 12v, so they were not getting power.

lots of other checking, but let's get to where I found the problem:

Battery Junction Box (fuse box under hood). There was no continuity between fuse 72 and pin 3 of the PCM relay. The relay would click (getting signal on pin 1 and 2), and it was opening the main current coil, but there was nothing to pass.

Because the PCM relay is way in the back of the battery junction box, it was not properly tested until last when I had the bolts off to the BJB so I could pull it forward and tilt it up to see/reach it with a probe.

I can see the contact pad inside the BJB for pin 3, I can probe it with my multi-meter, no continuity from fuse 72, which is what feeds it.

When I jumper power to pin 5 (other side of pin 3), or any of the other PCM fuses (33, 34, 36, 37 are all fed from the pcm relay) then i can get access to the PCM, and actually start the truck, but it will cough and die after 2-3 seconds, which isn't a big deal, I expect fuse 72 powers other things that are probably unpowered right now because of the break inside the BJB.

Fuse 72 does have 12v, so for pin 3 of the PCM relay to not have power means it's a break inside the BJB. Feeling around the back, I see it's a rather thick yellow wire with a red line on it. I see a bit of a pinch in the wire, and the usual green corrosion color, so I bet there's a break someplace thanks to corrosion, and sometime last week was my lucky day for the rain to finish me off..

In case anyone else is having an issue, it could be this.

Now I have to see if I can pull that thing so I can check the underside, I can't see the connectors that release it from the main harness, but perhaps a new day will help focus me.