brooksse, I work with data busses and I spend alot of time analyzing data which is transferred on various types of busses. Our trucks all have CAN networks in them and almost every sensor and electronic device in our trucks contributes to messages which are transferred over the CAN bus. If one of those devices dumps a bum message onto the bus, it can create havoc with the system. I suspect that this is indeed a software bug and it is causing a bad message to be sent across the CAN bus. That in turn causes the speedometer to crash. It will take a CAN network analyzer to confirm this. Of course, somebody who is good with a logic analyzer could probably debug this too. My gut feeling is that this problem exists in all the 2005 and newer 6.0L diesel trucks.

 

The dealer replaced the speed sensor and I was able to immediately make the problem reoccur. The dealer is not sure what to do next, I am waiting to hear from them. I believe changing components is not the answer based on Whalerron's experience. Can't they snapshoot some live data and send it to a Ford computer tech to troubleshoot? That's what I would do.

Whalerron, I think you might be right it could be the same for all trucks, it's just people don't normally drive them like this so they never see the problem.

 

Yes, somebody could fix this if they would put a CAN data analyzer on the CAN bus in our trucks. Only FORD will have that equipment. There is no way that the dealer would have this. The question is, can we get Ford to ante up to the problem and fix it?

 

Finally, I have an appointment scheduled with a Ford engineer on Monday, Sept 29. He is going to take a ride in the truck with me and look at the problem. This should be interesting.
brooksse, if necessary, do you mind if I mention that your truck is having the same problem? Maybe he would want to talk with you too? I am hoping that Ford recognizes that this is a problem in all of the Diesel superduty trucks and maybe they come up with a real software fix for it.

- ron

 

Hi.

Did you guys ever solve this problem? I have exactly the same problem and I read from your other thread that you where told to speed up once in a while. Like you I don't have that option
(https://www.ford-trucks.com/forums/7...tic-truck.html)

I use my truck to drive around the highlands of Iceland in deep snow where I need both the low range and all the power I got frequently and this problem is killing me

The truck I have is F350 6.0 automatic, SCT livewire with innovative tune.
46" tires and 5.13 ratio. New VSS, no ABS lights or other warning lights and no mods on the speedo.
Here is a 45sec video you might like
Ford F350 46" in Iceland - YouTube

Hope you got some answers from Ford :/

Ivar

 

Sorry, but I don't have good news for you. I drove around with a Ford Field Representative and he told me exactly how to reproduce the problem. We drove around and he could make it happen "at will". That proved he knew what was going on. Then, he told me that Ford would not fix the problem. It is a bug in their software for at least the 2005 diesels and a fix was simply too expensive to implement.

The problem occurs in a high torque, low speed, relatively high RPM situation. The software gets confused and it causes the speedometer to die.

This is a big issue for me too because it happens when I have a full load of firewood in the truck and I am crawling out of the woods. The "limp" mode really kills the power of this engine!

I am curious. What year is your truck?

- Ron

 

Sorry, I forgot to put that in
It's a 2005 (or 12/2004 but '05 MY)

This is not good news :/ But like you say, low speed, high rpm, low range is what is happening.

Have you tried maybe truespeed or some similar device and make it show 10x your real speed? Maybe that will solve the problem.
I should also ask Eric at Innovative diesel if they can write tune that reduces this or even buy some stand alone system if it's available.

But thank you for this answer, then I will stop looking for bad wire or replace the vss again.

Ivar

 

What is "true speed"? I haven't heard of this. Let me know if you hear anything from Innovative Diesel about a tune. The Ford rep told me that the computer generates a speed data message which is sent over the CAN bus to any device that wants it. In our trucks, that message is consumed by the radio and the speedometer. The speedometer only reports the data that is in the message.

- ron