stackz

06 5.4 3v truck w/63k on the clock.

driving to work this morning over a narrow bridge suddenly I hear a ding. I think its the gas warning but look anyway. it says "engine failsafe mode". then I realize I'm losing friggin speed on this bridge...in the middle lane.

I try to rev it and nothing so I toss it to neutral and turn the key off real quick and back on and nothing. hit my emergencies and get over as much out of the far lane as possible. get to a stop and I toss it in park, turn it off, wait a second, and then crank it up and it cranks like nothing is wrong.

then I finish heading into work in the right lane just in case. no more hiccups.

what is this mode thing and what does it mean? I'm going to try to research it some more today but I'm at work and have limited time so I figured I'd post here first just in case.

lifted07

engine fail safe is where there is an issue electrically with the engine but the computer will put it in that mode so you can limp to a mechanic or figure it out! i love the damn thing! my ecu went to **** and fail safe let me drive around under 40 to get it to the dealership! but unltimantly it is so you arent stuck wherever you are when an electrical part goes out!

Mod (Ret.)

Gotta take time to read your owners manual. As the above post points out, it's a "limp home mode" meaning some sensor or engine device detected a failure or reading causing the PCM (powertrain control module) to allow the engine to run, but without damaging itself.

Explained in the owners manual. Don't have one? Download a PDF for free here:

https://www.fleet.ford.com/maintenan...ls/default.asp

stackz

yeah, just had a chance to look through the owners manual at lunch and its kinda funny how you can have both a check engine light AND an engine failsafe mode as well.

reading the handfull of past threads on here, looks like its mainly associated with the drive by wire system.

I'll put my obd2 scanner on it this afternoon though when I get home. hopefully I get some codes I can go by.

Energy fiend

I had this same problem last summer. I know I got ripped off at the mechanics but he had to replace the throttle body. From what I have read that problem can be cured with a good cleaning on it. That's only if that is the issue with your truck though

stackz

ok, well I hooked it up to my obd II scanner and got no codes.

I also looked at the engine parameters at idle and all seemed well and while I was driving and saw no glitches.

I'm going to see if I can find the PID for the truck online and datalog all the engine sensors but at this point I'm leaning to the throttle body. what all needs to be cleaned on it? the inner bore or the egr passage?

all I know is this is if this is a glitch its one that I dont want happening too often....

Energy fiend

It happened with my 05 4 times before it finally threw a code. I'd say clean all you can in the area including the MAF.

stackz

several months pass by and no problems then 4 days ago...driving to work and suddenly engine failsafe mode and the engine is off again.

I dont get a "limp mode" like you guys are saying. the truck just completely shuts down on me.

I just pulled into the center median as I had nowhere else to go and turned the key off. sat for 20 seconds and it cranked right back up like nothing happened.

again, obd2 scan showed no codes.

its scary as hell when it just randomly does this to me and very irritating that I get no code so I have no clue what is having the brainfart in the engine bay.

D.WRECK

Happened to my 07 HD recently. Paid 400 to replace the throttle body and didn't cure it. Replaced the MAF, didn't cure it. Paid 700 to replace the computer and it fixed it.

Richar Itziar

My 2004 f-150's engine failsafe mode came on, around how much does it cost to fix?