I was out of town yesterday & stopped at gas station quick and started my truck and started down the road and I got a failsafe mode alarm. I waited a min then it re-started and then I drove 4hrs home non-stop & it ran great. So what's the deal I have never seen that before? Should I be concerned or take it in? I just ordered a tuner from VMP and I should have it soon but am a liuttle nervous about doing anything with it!

 

I've seen two or three reports from others who have had this happen to them. It doesn't seem to be a common thing, and it doesn't seem to reoccur. I wonder if there's possibly a service bulletin out on it? Sounds like something that might be corrected with a PCM firmware update.

I'd certainly ask your service adviser about it the next time you take your truck in for service. But in the meantime, I'd probably not worry about it unless it happens again.

If you DO get a programmer with custom tunes and your PCM is reflashed, the tunes will have to be rebuilt. That's a minor annoyance, but it's something to keep in mind.

- Jack

 

If you take a search of the V8 & 2004-2008 forum for Failsafe mode ( might also want to try Fail safe mode as well in both ) there are a few threads that say the PCM being reflashed, and the TPS ( Throttle Position Sensor ) were the fix for the exact symptoms those members had.

Not sure if the symptoms are 100% the same as your symptoms, I only took a quick read of a few threads ( and had not done the Fail safe mode search ).

https://www.f150online.com/forums/2004-2008-f-150-80/

https://www.f150online.com/forums/v8-engines-24/

I have not seen this myself, so I cannot comment on it.

 

Hey thanks for the info. It seems to be running fine. I did see some of the other posts on line. I am going to contact my dealer & see what they say or if they have seen it before. My tuner is on its way now. What do you mean by my tunes would need to be rebuilt if my PCM is reflashed? Is that if I have a custome tune in it & it reflashed?

 

If the programmer you have ordered is coming with custom tunes already installed, they are built for the HEX code that currently identifies the firmware in your PCM. They would only work with that HEX code. If your PCM is reflashed, it changes the HEX code in your PCM.

But, if the programmer you have coming is currently loaded with "canned" (the more "generic" tunes), then it will work fine after the flash too.

In either case, you MUST make sure your truck's PCM has been set back to it's stock tune before you take it in to the dealer for a reflash. You do this with your programmer. It's actually a good idea to always set your PCM to stock anytime you visit the dealer - they sometimes apply a reflash to correct a known issue without asking you first.

- Jack

 

Well I stopped by the dealer yesterday to ask him about this failure. He told me that if it has not comeback on and I have driven it that much it may have been just a hickup in the PCM or I did fill the truck and it did over fill and that may have tripped it. Like I said It has not comeback on and I have no loss of power at all. So I think I am just gonna keep an eye on it.