Reduced Power / Powertrain malfunction warning while towing (running a tune)

[Hambone437]

Here is kind of a long story of my adventure this weekend. I have towed my travel trailer several times over the past couple months and this Ranger tows amazingly well!!!

However, this past Thursday I was towing my 3800# travel trailer up a grade while going camping and I got the dreaded wrench warning light and the check engine warning light. I also got a warning on my phone through the Ford Pass app which warned of a Powertrain malfunction and reduced power. Holly cow I definitely felt the reduced power going up a grade! I was flooring it and loosing speed! Luckily I made it over the top of the grade and I limped my truck Into the campsite where we were going.

The Ford Pass App gave a little further information stating that the engine control system has detected that the turbocharger is outputting lower boost then expected. We called the dealer in my area and they said they would not be able to look at my truck for almost a week! Weighing my options, I decided to limp my truck back home without the trailer.

Im running the SCT tune on my truck and I wondered if that caused the issue. Nevertheless, I wanted to restore the factory tune prior to taking my truck to the dealer. Since we were camping on the river only about 18 miles from my house, I limped my truck back home and removed the SCT tune and restored the factory settings. In doing so, it also cleared the error codes. I drove my truck around town for several miles without any issues. We drove back to the trailer and camped the rest of the weekend.

I was able to tow the trailer back home today without any problems on the stock tune. I’m hoping that it was the aftermarket tune that created the error, although I‘ve been running the tune for several thousand miles without a problem. However, I don’t plan on reinstalling the SCT tune anytime soon, if ever...

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[Frenchy]

So where there is a possibility you will have a underboost condition code. If so there is a bulletin already out for that to reprogram the PCM. Good news is you do not have a tune so you don't have to worry about the dealership going and questioning things.

 

[geophb]

Underboost codes are pretty common in the ecoboost and powerstrokes.
You know what code it was? The sct tuner should be able to pull it.
Check all the vacuum lines and intake pipes for leaks. Make sure all the clamps are there and are tight.

 

[tjanok]

With the tune you're running higher boost for longer durations. This caused my factory BOV to develop a very small tear in the gasket/grommet thingy. A turbosmart one solved this issue. I have the same exactly problem (+ a hot pipe coming off) in my Focus.

 

[Vino]

I have also ran into this issue while towing my bass boat and running a tune. All you have to do is turn the truck off and turn it back on to reset the issue for the time being.

note: I was running my performance tune instead of the towing tune when this occurred.

 

[ken91773]

Problem solved!
I got the same indication while towing a 3000# trailer near Vegas in 114 deg heat. Turning it on and off did not reset it. Tried to go straight to a dealer who didn’t care I was stranded and told me they could get me in at the end of the week. Decided to spend the night at a hotel, do some research, and found it simply meant the transmission oil was overheating from towing. Why didn’t it just say so? Sure enough after a couple hours of sitting, I restarted it and the warning was gone but the check engine light was on indicating the underboost condition. I cleared it with my OBD2 reader and continued onto Wyoming without any further problems.

Also if you want your transmission oil to run cooler while towing, I recommend downshifting to a higher RPM around 3000-3500. I used to do this in my F350 Superduty with engine and trans temp gauges and when the engine runs faster and hotter, the transmission runs cooler. However at some point it may all get too hot.

 

[P. A. Schilke]

Problem solved!
I got the same indication while towing a 3000# trailer near Vegas in 114 deg heat. Turning it on and off did not reset it. Tried to go straight to a dealer who didn’t care I was stranded and told me they could get me in at the end of the week. Decided to spend the night at a hotel, do some research, and found it simply meant the transmission oil was overheating from towing. Why didn’t it just say so? Sure enough after a couple hours of sitting, I restarted it and the warning was gone but the check engine light was on indicating the underboost condition. I cleared it with my OBD2 reader and continued onto Wyoming without any further problems.

Also if you want your transmission oil to run cooler while towing, I recommend downshifting to a higher RPM around 3000-3500. I used to do this in my F350 Superduty with engine and trans temp gauges and when the engine runs faster and hotter, the transmission runs cooler. However at some point it may all get too hot.

Hi Ken,

Yep...there is a balance in extremely high ambient temperatures. When you downshift, you increase the speed of circulation of the engine coolant which helps keep the engine cool. It does get to a point, like Death Valley, where we test that the Temps get close to overheating, but if we discover during testing, it is back to the drawing board to increases cooling capability. However, since weather is variable, it is possible to be in a situation where ambient temps exceed the design parameters. Under these circumstances, back out of the throttle and down shift and take it slow and easy are the recommendations if you do not pull over and let things cool down...keep the engine on and A/C running but no load of a trailer under tow. Very surprised your F350 overheated...pretty much bulletproof....What mods if any on the 350. How old as well.

Best,
Phil Schilke
Ranger Vehicle Engineering
Ford Motor Co. Retired

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