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5.4L Fail Safe Mode

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Old 10-09-2009, 10:38 PM
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Default 5.4L Fail Safe Mode

3 times in the last 6 months my engine went into fail safe mode for no apparent reason. Each time, I pulled over, shut the engine down and restarted it. No problem thereafter. Anyone have the same problem, and, if so, what is the cause?
Old 10-10-2009, 01:43 PM
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Are you getting a trouble code? If so, what is it?

Fail safe or "limp home mode" is usually because of a significant sensor failure (I.E. MAF, low fuel pressure, etc.). There should be a code stored.
Old 10-10-2009, 08:09 PM
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I'll put the Actron on it tomorrow and see if it has any stored codes. Thanks for bringing that up. It scares me to have this intermittent problem because if it occurred during a close quarters pass, it could be quite interesting!!!!!!
Old 10-11-2009, 01:06 PM
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Put the Actron CP9125 tester on the truck today and it showed 0 codes!!!! Anyone have another suggestion? Thanks.
Old 10-27-2009, 06:01 PM
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Next time it happened, I left the truck running and put the Actron on it. Got 3 codes and gave them to my dealer. They said I needed a new throttle body. That has been done so i shall see if the problem is solved.
Old 01-28-2010, 02:11 PM
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hi my 04 screw went in to fail safe mode as well then the low oil pressure displayed on the screen. i drove it about 10miles home and it used almost a half a tank of gas, does any one no what could be the problem. getting codes read tomorrow. thanks valleyboy

as ive been reading other threads ive noticed bucko is quite knowlegable on this topic.
Old 01-29-2010, 11:36 AM
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A coworker of mine owns a 2005 5.4 that had this issue, I have this issue with my 5.4L. This morning in 4F weather, truck stalled twice on me, wrench light came on first time, check engine the second. Sounds like if it happens twice with in a 15 minute span, throws the check engine light codes. Turns out that he went in and cleaned the throttle plate and the issue went away. I just did that, I will see how it goes on my drive home today. Sounds like it should work.
Old 01-29-2010, 11:52 AM
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Originally Posted by formakos
Next time it happened, I left the truck running and put the Actron on it. Got 3 codes and gave them to my dealer. They said I needed a new throttle body. That has been done so i shall see if the problem is solved.
Drive by wire gets another victim. Sad thing is, everything is drive by wire now. I thinks it's a dangerous design. What if someone is entering a freeway and the thing goes into idle and won't accelerate?

Mechanical begets electrical sometimes.....
Old 01-29-2010, 10:45 PM
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reset the comp

1. disconnect the neg battery lead.
2. tap the brake pedal(to drain any power in the system by lighting up brake lights)
3. wait 30 sec. or whatever long..
4. re connect the battery..

tthat should do it
Old 02-01-2010, 08:46 AM
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Update: After cleaning the throttle plate friday lunch time, the truck has not stalled out into failsafe mode at all. This morning it was 7 F here in Detroit...had I not cleaned the plate...would have stalled. Seems as though this may work...

I also talked with a few others over the weekend who go in and clean their throttle plates every oil change or every 30K miles are so...


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