I've been pinging a bunch of forums trying to see if anyone has seen anything like this. I went out to start my truck the other day, and got a no crank condition. Theft light is flashing at me, and it says "CHECK BRAKE SYSTEM" "TRAILER BRAKE MODULE FAULT" Won't even let me shift into neutral to roll down my driveway. What's weird is my MiniMaxx buttons aren't working. I've already checked the pertinent fuses to no avail. I have the shop manual, and the pinpoint test for no scanner communication with the TBC seems to indicate that it's a bad TBC. I've tried leaving the Mini disconnected when starting, and it doesn't seem to make a difference. I did leave the batteries unplugged overnight, and it started up normal, but this morning, it's all locked up again. I have noticed that the TBC display no longer lights up when I turn the key on, and it does have key-on power at the plug. Has anyone seen anything like this or had a TBC go bad? I don't want to buy a $300 TBC if that's not the issue.

VID 20130212 210651 - YouTube

 

Moved to the 6.4L Power Stroke Diesel forum.

 

You can unplug the module to eliminate it as the cause.

Below the aux power and the 4x4 switches there are two little pieces of trm that come out with a screw driver. Behind that are one bolt for each side. I think 8mm.

Once you take those out you can remove the entire trim around the radio/hvac/and stuff.

If I recall the module comes out with that. Then you should be able to access the wiring behind it to unplug it.

See what that does.

Possible it is some moisture at the plug by the reciever causing some problems as well so check all your wiring from recieve on back towards the cab.

 

I've tried unplugging it with no luck. I was getting the "Trailer Wiring Fault" message when it rained because the cover to the plug was broken off, but I removed the trailer plugs entirely to eliminate that possibility. I can't find anyone who's had these exact symptoms

 

tough one..I have never heard of what you have either. Perhaps the sensor for the TBC at the master cylinder maybe bad?

 

I swapped in a TBC from a good truck, and still no change. Anyone have more ideas?

 

Just the sensor at the master cylinder.

Check with the tuner people and see what they say.

 

Well, after much frustration and profanity:

VID_20130315_195233 - YouTube

Loose lug off the positive battery terminal clamp. Glad it was simple, but what a bitch to find.

 

Don't you just hate it but love the easy fix as well!