Hello all, I have a bit of a strange one. My 2015 Crew cab Lariat with the 3.5 Eco Boost is going into limited boost (6 p.s.i.) after pulling a long uphill grade with my 6K lb. boat and some gear. This seems to happen in higher ambient temps 75 - 90 F. I also get the P0299 low boost code. The truck is equipped with the max. tow package.
If I stop, turn it off and restart, it's fine again till another long pull. I do have a winch and bumper on the front limiting some airflow to the intercooler.
Has anyone run into this and if so, How did you resolve it? I don't really want to remove the winch. What sensor would I watch to tell if it's ready to go into limp mode?

 

From the PCED Manual

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.

 

Thanks for the Quick reply 52merc.
Those were the normal diagnostics that I started with. Short of installing camera's looking at the wastegate action when this happens, I'm not sure what to do next other than pulling the front bumper next time I make the trip over the mountain. Just curious if anyone else has a winch and tows heavy trailers that doesn't have this issue.

 

Can't help you there. I would think if it is related to the CAC temperature being too high due to the bumper, a different DTC would be initiated.

 

That's kind of what I thought. I watch as many P.I.D.'s as I can related to heat and nothing was out of whack that I could see.
About ready to install a Radiator water spray kit to cool the intercooler to see if that helps. Might be next summer before I can test it though. Lakes are getting low here.

 

You tow heavy (weight plus grade) regularly and have limited the factory efficiency of your intercooler that some believe is not that great at heat shedding when towing by adding the winch. I would say an upgraded and relocated intercooler is in your future. No sprayers to worry about, and much improve charge air cooling.

 

What kind of engine and transmission temps were you hitting? They are known to pull boost when higher temps are hit.

 

Engine and Trans. temps never moved from normal. I'm kinda leaning towards JustaV6's comments. When I stopped onetime, I felt the intercooler and it seemed pretty warm. Temps on the intake side never reached 120 Deg. F though, which was a max reading on my data logger. I can't find the limit spec. anywhere. I would think there would be something on that subject right?

 

Which intake temp maxed below 120*F? Granted I'm tuned, but in summer heat and stop/go or parking lot idling (not towing) I've seen temps as high as 130*+ IAT and 150*+ IAT2, without problems or codes or boost limitations. Normal engine and trans temps at the time.

 

I'm assuming it was downstream of turbo/intercooler. I was reading from TorquePro Intake temp. Yeah, I also saw the highest temps. while in traffic.
I'm perplexed. I'll have to research to find the pids for all three sensors. I know there are two downstream MAF sensors. Does the PCM look at the difference between the two? Maybe its just a bad MAF sensor but I'm hesitant to just throw parts at the problem. Maybe that's the answer. Spray and pray?