Today on my way up to go dirt bike riding my truck went into engine fail safe mode and the check engine light came on while driving about 25 mph down a gravel road (barely on the gas). The truck was driving just fine before this happend. After my ride I got the codes read in town at Oil Can Henry's. Their reader didn't give the actual code, which I thought was strange, just a description. The codes are:
1. camshaft position
2. camshaft position
3. MAF A circuit malfunction
4. sensor heater circuit malfunction bank 1 sensor 1
5. sensor heater circuit malfunction bank 2 sensor 1
6. evap emission control system purge valve C fault
7. evap emission control system vent circuit malfunction
8. system forced limited power

I am assuming that one problem threw all these codes since it all happened at once and just want an idea of where to start. I was thinking maybe a cam position sensor went bad, but really have no idea. #8 is just the engine fail save coming on due to one or all of the other codes. the forced limited power is the only thing that is noticeable but it could easily be masking one of the problems, I wish I could force it off somehow.

Oh, and I have a 2004 Screw with the 5.4 and just over 70k on it.

Thanks in advance for the help.

 

Do yourself a favor and buy a code reader. They can be bought for as little as $30. sometimes. Plenty of help on the net as far as looking up the definition of the codes. CANCEL the current codes (if they haven't already been) and see what comes up FIRST when the light comes back on! Whenever you have a flurry like that, you have to cancel and give it's brain a little chance to come back to earth, Scotty. You might even want to cancel THAT code and see if the same thing comes up again, and how soon. THEN you have something to work with, right now you don't.

http://www.obd-codes.com/ Find your way around this site. A LOT of good information there. Make sure you check out the WHOLE site!

 

While a code reader is handy, you don't need one for this problem.

Assuming a "new" 2004, you probably blew fuse F32 in the central junction box (CJB). That fuse supplies power to a number of devices , all of which are named or related to all of your fault codes.

If it were warmer weather, you would also have notice that your A/C isn't working since the clutch coil also is fed by that fuse.

Verify if that is the problem. If so, we can go into the likely causes.

 

I was going to swing by autozone on my way home from work and borrow a reader from them so I can get the actual codes, but if I see one for $30ish I will probably just pick that up. I had the codes cleared last night when they were read, but they came right back on within about 30 sec of starting the truck so I had them read them again and it was the same eight codes.

Wow projectSHO89, I really hope that is the problem! I do have the new 2004 style so I will check that tonight right when I get home unless I can get the wife to check since she is home (doubtful though, she probably couldn't find the fuse box let alone the fuse).

 

You've got a LOOOOOONG way to go to break the record. I've pulled nearly 30 from a Land Rover DiscoII (yes, it was still driving), and Land Rover Range Rovers store more than 20 fault codes when everything's working exactly right.

Click this & follow the link in its caption:

 

projectSHO89, you were exactly right! Fuse 32 was blown so I put another in there and it blew right away upon starting the truck. Any insight as to what could be causing this?

 

So I just checked the actual code numbers and they are:
P0010
P0020
P0102
P0135
P0155
P0443
P0446
P2106

 

Don't worry about the codes, they're not relevant on this problem now.

Most common would be an upstream O2 sensor harness that is laying on the exhaust, or, if a 4x4, on the front axle. If that's not it, you'll need to run the wiring harness looking for chafes or pinches that are causing the power line to short to chassis ground. This will NOT be easy unless you get lucky! The subject wire is RED/YELLOW and goes to a variety of sensors and actuators under the hood.

 

Yeah, I just unplugged 3 of the 4 o2 sensors and it still blew the fuse. I have one more fuse until I have to run into town to get more. Gonna try to check all the wires now before I use it. Wish me luck.

 

I think I found the problem... just not sure how I'm going to fix it. Its above the upper passenger cat, there's a plug that seems to have melted to the exhaust. I know the pic sucks but I put as much light on it as I could and the flash was useless since there was a bunch of stuff in front of it. That gray piece in the middle is a plug that has melted to the exhaust. Now I just gotta figure out if I need to take the exhaust off to get to it. If I go through all that then this better be the problem.



Thanks for the help projectSHO89! I'll be sure to post my progress once I have made some.

 

I got it zip tied up and away from the exhaust and it seems to be fine. Codes aren't coming back and no more engine fail safe mode. The real test will be the drive in to work tomorrow morning.

 

Upstream O2 sensor harness! Get it sealed against corrosion and secured away from the exhaust and you should be good to go!

You may have to remove the RF wheel and fender liner to really get in there.

 

I got it away from the exhaust, but didn't seal it. I took off the RF wheel and was able to get my arm up under the inner fender and was just barely able to reach it. It's zip tied and wired up away from the exhaust, but I didnt seal it as I would have needed to remove the inner fender and I didn't want to do that again. Last week I took the inner fender out to put the elbow on the AC condensation drain out of the firewall to keep it from soaking my passenger side carpet. I figure I must have pushed this wire down near the exhaust when I was doing that and didn't notice. If corrosion becomes a problem I will just order a new harness and remove the inner fender and replace it, but that was more work than I had time for last night.

The drive into work was uneventful and everything seemed back to normal.

projectSHO89, you must have had this same thing happen to you or something because you knew exactly what the problem was from my first crappy description. Either that or you are an F150 god. Thanks again for your help, I would still be trying to track this down without it.

 

Glad it's working out for you.

Too much credit there, I'm none of those. I'm just a guy who was well trained (Army) a long time ago to understand and diagnose complex electrical, electronics, and electro-mechanical systems. The missile systems and test stations I learned on were a bit more complicated than trucks, although these trucks have become literal "networks on wheels". Working on my Fords is just an "activity" to keep from paying someone else $100/hour for something I can do myself.

 

Not to HIJack but I had almost the same codes, same situation. Thanks for the good lead "projectSH089" right on the money, and thank you for your service.