I have a 98 F-150 V8 long bed that I use to tow a two horse trailer. It has 3.73 LSD and all towing options (heavy duty cooling system, alternator, etc). I am towing at the very most 7000 lbs and using a weight distribution hitch, but usually around 5000 lbs. I tow my horse to my trainer's or to a show maybe once a month. The truck pulls this fine.

The last three times I have towed my horse, the "check engine" light has come on. The first time I immediately called the Ford dealer to see if this was an emergency. They told me to bring it in but if all the gauges looked fine and the engine sounded fine that it was ok to drive it. Before I was able to get to the dealer, the light went off. The dealer then told me that unless the light was on, their computers could not determine the reason for the light. Twice more this has happened and the light has gone off on the drive from the barn to the house so we have not been able to get this checked out. I am now getting worried because a friend's 2000 F-250 diesel recently broke down on her on the interstate with her horses in the back. She was told that her cam sensors were not working properly.

My question is this: Has anyone else had this problem? If so, what did it turn out to be? I am always nervous driving with my horse in the back and the last thing I want is to break down on the side of the highway! Thanks for your advice!
keeley

 

the way that i understand the computer stuff is that if the light comes on then there is a code stored in the computer

it sounds like your dealer is not wanting to fix it

i would call another dealer and see what they say

 

It could be your throttle position sensor or one of the lines carrying air(vacuum or PCV). I would look for loose or disconnected lines and disconnect your battery for 5 minutes to reset the computer and try it again. If it comes on next time you tow, the fault codes need to be read cause it will definately have one or some.

 

If you are towing with the overdrive in the "ON" position you will get this problem. It should be turned "OFF" when towing.

 

My 97 XLT 5.4 3.55 towing a 20' camper @ 11,000 GVW.

WOT up a moderate grade at 70 immediately prior to exiting the freeway with 200 yards of no throttle.

Light came on.

No symptoms.

Reset the computer 2 days later (battery cable off - lights on).

Never did it again for well over a year until trading it off.

I suspect that the fuel chemistry sensors got excited about the WOT followed immediately by no throttle.

It has been reported elsewhere on this board that the computer will reset the code if all's well for x on/off cycles.

 

THANKS for all your helpful suggestions! I do always tow with the overdrive "off" so that's not it. Y2K, what is WOT?
keeley

 

Keeley,

I also tow about 7000#. My boat will generaly weight about 7200# depending on how much fuel etc.

Anyhow, I tow with OD on 100% of the time, and I've never had any light come on. The computer will manage the tranny and when and where it shifts. With the mods I've made including the chip, that may be part of the reason I have no problem. When I hit a grade of hill and it does drop into 3rd, it stayes there until conditions permit an easy safe shift back into 4th.

And I agree, it sounds like the person you talked to at the dealer either doesn't know any better or doesn't want to look at it, which wouldn't make sense. If it errors, it's stored until reset. Maybe another dealer?

 

Does it happen only when you're actually moving or does it happen when you sit there in neutral and rev the engine too?

Does it happen even if you don't hook up the trailer connector?

What kind of trailer brakes do you have? Surge, electric, or vacuum?

 

(W)ide (O)pen (T)hrottle

(sorry)

P.S.: The Y2K manual does not advise not towing in Overdrive.

 

Once the light goes back off the code has been dumped from memory and the truck has not experienced the problem that set the code for three cycles of use. It must be hooked up to the code reader while the light is still on. Your dealer is correct. What causes this? Well... O2 Sensors, Throttle Position Sensors... things like that in the emmisions monitoring systems. Could be the situation only occurs when towing and is a slightly sensitive sensor. Might be getting ready to go out. I think 7K is a bit much towing for a F150 though. But I would not be too worried about this as the light does cycle back off. If it becomes more frequent then the light will stay set long enough to get to the dealer while its on. Or borrow someones ODB II reader if you can.

I would bet on the Front O2 sensor first and the TPS second. It will probably pop up both codes when the light is on but it will be the O2 sensor that is most likely the culprit causing the TPS to read wrong.

 

I have a 1999 F-150 with the towing package and the 5.4L
My maximum towing capacity is 8300lbs....
Your truck should be able to handle 7000 with a weight distribution hitch on!!!!

So you are not over limiting it. Pull the trailer get the light to come on and while pulling the trailer take it to the Ford Dealer and have the hook it up to the computer!

Just and Idea



Good Luck

 

Hey there guys, does this truck an aftermarket exhaust or duals?

I have been told if you install dual exhaust and you use your F 150 as a tow vehicle, you need to have your dealer reboot or reporgram your transmission accordlinly.

Maybe this helps, maybe it won't, I do not tow let alone even have a receiver.

ShowYa in Kansas City!

Just a word of advice I have heard around town from guys who have had this problem.

 

My light came on 6-10 times during a 7500 mile trip last summer. I reset it by disconnecting the battery--yes, the dealer can't find the code if the light is off. The last time it came on, I took it to a dealer in New Mexico, and he found a bad oxygen sensor. Since that has been replaced, it hasn't come back on.

 

Just curious, but anyone know why you shouldn't tow w/ OD on? How heavy of a trailer do you need to be towing to have to turn OD off? I've been towing with OD off, but wondering if I'd get a bit better gas milage with it on. The trailer I pull is less than 3500#, which is way below what my limit is.

Thanks

 

Remove the light and you wont have to worry about it!

(Just Kidding)