Hi All~
Just wrapped up a 3,500 mile trip to Montana with my 2017 F150 Lariat and got a hill decent fault 200 miles from home. Stated service required. Shortly after I was locked out of cruise control . Towing an Airstream with a weight of 5,500 lbs loaded and used tow haul throughout the trip. Never ran above 4,000 RPM’s and never had any ‘hot readings’ for engine or trans. Worried this truck is being asked to do too much. Will bring in to dealer tomorrow but somewhat nervous. Any thoughts here??

 

You might need to write down more details about your truck, engine, tranny, package...

I just did a 11 000 km trip this summer from (almost) the east cost to Wyoming and Montana. Got through crazy passes and grades. 7000 lbs 32ft trailer, 5 passengers. 4000-5000 rpm on many occasions going uphill as well as downhill. Mine is a 2018 XLT with HDPP package, V8 5.0, 10 spd tranny, 3.73 diff.

 

The only faults I get on my truck is when I'm towing and the reason is that the sway bars were not lubricated.

If the truck cannot align with the trailer, it throws off some sensors. I will get this shortly after pulling a way from a rest area, or such. It deactivates cruise control, driving modes, etc.

Once I lube the head of the WDH, the problem goes away. Try checking your WDH. I use an Equal-i-zer brand WDH. Where the bars go into the hitch, you need to lube.

Not sure if that's your problem, but that's what solved mine.

My trailer is 8200lbs, not truck issues.

 

I have a 3.5 Ecoboost with a 3.55 axle ratio. Also use an Equalizer hitch and for 2 years everything has been perfect. Keep things well lubed. Wondering if the Ford service center I visit tomorrow can read the fault history as I obviously will not be towing the Airstream to them and there are no faults showing now that trailer is not connected?? This is new territory for me.
Thanks for your feedback!

 

5,500lbs shouldn't cause any problems /w that engine setup. If I had to guess it's just a problem /w the hill decent system and isn't related to you pulling a trailer, just happened to fail while you were towing.

 

I have not had any issues with my 2017, although I have a bit more umph to your model. I'm curious to know what the dealer find out, keep us posted!

 

Did you get an AdvanceTrac error message too, by any chance?

I've seen that once or twice, and there's a thread over in the main 2015+ forum about it, and my scientific wild-*** guess is that the AdvanceTrac and Hill Descent systems rely on a bunch of sensor inputs. When a certain number (possibly one, possibly more) of those sensors aren't reporting something that makes sense to the computer, it throws up its hands and says "I can't do that, Dave" and turns off Hill Descent, Cruise, and possibly other systems that rely on those sensors and computers as a failsafe. I'd bet that a sensor failure, a wiring failure, or a computer failure can all trigger those warnings, and the actual codes are going to be more helpful for diagnosis than the dash messages.

Either way, 5500 pounds of trailer should be well within what your Lariat can handle, as long as you're not also loading the heck out of the truck.

 

It's the electronic throttle body singing it's swan song.