Hi everyone,

Hopefully I can get some suggestions from the group. My wife and I just got back from camping. We tow a 6200 lb trailer. Easily within my weight range for my 2.7 scab. (I've done the math) Not long after leaving the campground and filling my tank, I got the P0299 code and wrench light. Truck went into limp mode. Pulled over and shut it off. Started back up and it no wrench light. Off I drive. For the next 60 miles, the wrench light came back 4 more times. After the 5th time, we pulled off into a gas station, parked and went inside for 10 minutes for me to cool off. Came back out, started the truck, and off we went. No wrench light for over the next hour until we got gas. Even after getting gas, it never came on until another 45 minutes afterwards. I used Forscan lite to pull the code while on the side of the road. This code comes on at the most random times. I've checked the piping to the turbos and the intercooler. They all look good. Nothing seems cracked or broken. The waste gates work smoothly and the sensor down near the intercooler looks to be in good shape. Here's my questions...

1) which side is considered bank "A" for the turbos?

​​​​​​2) would topping off the gas tank potentially create an underboost problem somehow if the EVAP system was not functioning properly?

I'm working at breaking the habit of topping off my tank since I've read about all the negative affects it has on the EVAP system.

I never get any of this while driving without the trailer and when it does show up, like I said, it's so random. Any help or ideas is greatly appreciated.

 

Bank A (or Bank 1) is the passenger side. Can't comment on your second question.

Possible causes for a P0299 are:

• Damaged TC wastegate regulating valve solenoid
• TC wastegate regulating solenoid valve stuck
• Wastegate stuck open
• Wastegate control hose open or plugged
• Air leak between turbocharger and throttle

 

There is ONLY one sensor (combination pressure/temperature) in the 2.7 system for turbo boost pressure - located in tubing inlet to the throttle body. (It just happens to be labeled "A"). The intake manifold has a separate pressure sensor for PCM intake air/fuel ratio calculations. As 52merc has list the WSM says:
P0299 - Turbocharger/Supercharger A Underboost Condition Description: This DTC sets when the actual TCBP value is less than the desired TCBP value by 27.6 kPa (4 psi) or more for 5 seconds, indicating an under boost condition.
Possible Causes: • Damaged turbocharger (TC) wastegate regulating valve solenoid • TC wastegate regulating solenoid valve stuck • Wastegate stuck open • Wastegate control hose open or plugged • Air leak between turbocharger and throttle
Diagnostic Aids: Check tubing for restrictions, cracks and incorrect fitting connections. Check the turbocharger wastegate regulating valve solenoid for correct operation.

Are the turbo wastegate valves being properly regulated?

 

The regulators for them are working properly. I checked them with a vacuum pump and they opened at the proper psi.

 

Thanks for clarifying 52merc. At least I know which side to focus on.


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OK forget my silly answer. See attached for info and diag process applicable to most all F150 recent turbo engines.

 

I misunderstood what you asked earlier and had a silly question, which I deleted once I understood what you meant. I'll check out that video. Thanks

 

So I'm doing some more diagnosing today due the underboost issue. I pulled my intercooler and found this. It's so slight that I'm not sure if it's an actual leak or just some residual residue from something else. Again, this code only comes up when towing so I think this may be my culprit but I'd like some input from guys who are more knowledgeable on forced air systems. I don't see anything above it that could leak onto this area and cause the residue. Maybe and hot/cold temperature changes cause the plastic and aluminum to flex and separate over time? The rest of the intercooler is completely dry.

 

Looking at your picture, it appears to be oily reside and dirt on the UPPER DRIVER SIDE CORNER. If so, you are correct when saying "I don't see anything above it that could leak onto this area and cause the residue." (Just looked at mine (2015 -2.7) to confirm). Because this is not a DTC that would effect engine damage in the short term - I would try cleaning this area up (spray can brake clean), reinstalling and then drive awhile to see if it re-appears. This would confirm your suspicions.
Another thought.
Is it possible for the bypass valve or bypass canister is causing this (if indeed it is the UPPER DRIVER SIDE CORNER? If it is the passenger side then nothing else is around it to cause the oily/dirtly residue.

ADD comment. By the way, the control of the turbo waste gates on the 2015 2.7 is via VACCUM not pressure as in the video referenced earlier.

 

This is the upper passenger corner. I did think about cleaning and reinstalling to see if the residue comes back. I checked all around the area above it and nothing looks to be close enough to be causing this residue. Radiator isn't losing fluid. Power steering lines are in good shape (even though they're near the center of the intercooler). Air conditioner lines aren't leaking. I guess the only option is to clean and reinstall and check again in about a month when we go camping again. I have another 4 hour drive each way with the trailer say that will most likely be the tell tale. Appreciate your input on this Home 2#7.