So I posted this over a year ago and never figured the issue out. Like all things, it went a way for awhile, I forgot about it and then when I least expected it, the problem came back.

2005 5.4L F-150 SCrew Lariat

My truck will randomly go into Fail-Safe mode. It happens at all speeds: on the freeway at 80-mph, in residential neighborhoods at 25-mph and cruising through a parking structure at a near crawl while searching for a spot. It seems to happen when it is cold out. When I mean cold, I mean Southern California cold, like < 50 degrees or so. It never happens > 60 degrees. My Edge spits out the following trouble codes:

P2104 Throttle actuator control system - forced idle
P2111 TAC system - stuck open
P2112 TAC - stuck closed

I run Level 2 programming with zero modifications and 89-Octane. I've been running these settings since I bought the gadget back in 2006 or so. This problem just started a little over a year ago. And like I said earlier, it only happens when it's cold out, so sometimes I'll go months without having an issue. Now that it is Winter, the problem has returned.

Anybody else having these issues or know any possible fixes? I'm well out of warranty, so taking it to the dealer is a last resort.

Thanks in advance!

 

Had it happen once about one year ago I think and again earlier this week. Do not know the codes and do not see any commonality in conditions other than I was in a 45mph zone at the time. Both times pulled over, turned off, waited several seconds, and cranked back up. First time dealer said unless it is a frequent problem not to worry. Got that general response from other threads as well. I am headed there now for something else and will inquire again.

 

Just an update...

The cold and rainy weather that we've been experiencing the last couple weeks would have surely reproduced the problem I was having. However, I had already removed my throttle body and gave it a good cleaning with some TB cleaner and all has been well since. So hopefully, this issue was simply to due to a dirty TB.

 

When i had this problem, after weeks of the dealership looking into it and even changing the TB, it ended up being 1 of the speed sensors on the tranny, along with the wire harness that connects them. When you said that cold and rain makes it act up, maybe you have a corroded sensor connector or damaged wire that is effected by the moisture. Just a thought. You should have been with me when mine decided to do it. I have a heaping load of firewood in my truck and pulled out of the feild i was in onto a road that was going up hill, and as soon as i got the truck straight from turning it took a dump. That was a long crawl up that hill with a line of traffic behind me!

 

Mine was doing the same exact thing. It died 3 times in the last 4 months. Finally got it into the dealership. They said the Throttle Body has an internal failure and must be replaced. Now they tell me no one has the part in staock and they need to speacial order from Ford. All this for just $659.00 Nice way to go into the new year.