Check Engine Light P0299 - Turbo Underboost

[G-556928]

You are Lucky LuvMyEncore.i bought my 2014 Buick encore in January 2019. It's been in the dealer for turbocharged problem 6 times in February,in March, in April now may. I took it in May 6 and "they fixed" today May 16 same problem. I will be taking it in tomorrow for the same problem. It's been 5 months 6 times.😡 Let see what they will say tomorrow. This car it's been a totally a nightmare. I'm worrying about my son safety. Because the turbo keep failing and is afraid being in the highway where he have to change lanes and the car don't accelerate to pass to the next Lane. Sometimes he have to pull over till traffic slow down. I had been in the ER due to the stress level been so high this car is driving me insane 😡 I pray everyday that my son is safe Everytime he drives the car. 6 times in the dealer for the same problem is ridiculous. GM should do something about it. I can't sell it and someone else to have this problem or get hurt. It can cause a pail up in a highway. Very dangerous problem.

Have u found the issue tho. Was it turbo forsure i have same issues only when its hot outside tho

 

[G-909117]

Just heard from the dealer. They contacted GM, GM said to replace the turbo. Of course no parts in stock but should have them tomorrow morning and have it finished tomorrow afternoon. And, they gave me a 2015 Verano as a loaner until it is done. 🙂

Did they charge you for the work?

 

[G-356277]

2017 Buick Encore with 35,000 miles error code P0299.Let's hope it's not too bad.

 

[Again]

I just repaired a Cruze with this code. It had just come from the dealer with a $300 bill. It turned out the underboost code was caused by 2 separate leaks. One was at the throttle body the other was at the entrance of the intercooler. I removed and cleaned both hoses and re-installed and tightened clamps. The guy said his Cruze never worked so good. I made myself a little gizmo to check the intake to see if it held pressure, it works perfectly.

 

[G-726375]

2013 Encore with 56,000 miles.

Got the check engine light last week, took it into the dealer, they inspected the turbo, declared it healthy, reset the check engine light and sent me on my way. 2 days later, check engine light is on again, OnStar verified the same P0299 error code, back at the dealer today... 🙁

This has happened to me this week

 

[Again]

Start by disconnecting the inlet hose to the throttle body and cleaning any dirt that may lay at the bottom of the rubber hose. wipe clean the throttle body neck. Slightly grease the inside of the rubber hose and re-install. Tighten clamp good. If 50% of the time this is where your leak is, the other 50% is at the inter cooler inlet, a bit harder to get at so do the throttle body first. Engine light should go away after 3 start up if you don't have means to clear the code at the port.

 

[Outtolearn88]

Start by disconnecting the inlet hose to the throttle body and cleaning any dirt that may lay at the bottom of the rubber hose. wipe clean the throttle body neck. Slightly grease the inside of the rubber hose and re-install. Tighten clamp good. If 50% of the time this is where your leak is, the other 50% is at the inter cooler inlet, a bit harder to get at so do the throttle body first. Engine light should go away after 3 start up if you don't have means to clear the code at the port.

Would you by any chance have a picture to show where.
Thanks in advance for your great information here on the forums. 👍

 

[Again]

Sure let me go to the garage and pop the hood.

 

[Again]

Red arrow points to clamp in question. I recommend you do not just tighten, remove and clean inside hose and re-install.

 

[Outtolearn88]

Red arrow points to clamp in question. I recommend you do not just tighten, remove and clean inside hose and re-install.

View attachment 31839

THANK you so much for clear explanation with picture 👍

 

[JCollazo]

02
I replaced turbo and 02 sensor on my 2015 Buick encore. Code 0299 and 0420 still did not go away. A couple of days later replaced catalytic converter and both codes went away.

Hey Joeyencore: Which catalytic converter did you replace? I'm having the same reoccurring P0299 code, but I just replaced the turbocharger in 2019; so I doubt this is the problem. I'm hoping that replacing the catalytic converter will make this curse go away for good!

 

[asdx1234]

There are 2 cats on these cars. Before I replaced the turbo I removed the second cat and had a piece of pipe welded in. This did remedy the P0299 code, but I still changed the turbo.

First cat is directly after the turbo where the First O2 (upstream) sensor goes. It is a round sort of balloon like canister that would not be fun to replace. I have not replaced this one, but I imagine it is not cheap. I can tell you that this first cat is responsible for making the car quiet. After replacing the turbo the clamp broke that holds the turbo to the exhaust pipe and the car was VERY loud driving it home.

The second cat is underneath the car about the middle of the car. There is also another item there which I have been told is a flame arrestor. I removed both of these items from my car and it did not really make it any louder but again it did fix that Po299 code.

I have also replaced the throttle body, and all of the sensors on the turbo.

Both of my O2 sensors have been replaced. I have an optima battery with new cables. Also a new alternator, starter, and water pump.

I still get a check engine light with Po420 stating bank 1 sensor 2 which is the downstream o2 after the first cat. The wiring all looks fine, but the guy at autozone told me he has seen this code many times before, and on the printout it states this sensor shows no activity which he said is most likely the wiring.

I can unhook the battery and the light goes off, but comes back on within a few engine starts.

I may go back to the shop that replaced the downstream sensor since it has been less than one year and still under warranty, but I doubt this would fix it, but worth a shot since it would not cost me anything.

The car runs fine does not miss has full power starts right up doesn't make any weird noises, but the gas mileage is not as good as it is with the engine light off. I will probably just live with the light, or I may drill a hole into it and turn the thing off. This would make a tiny hole in the instrument cluster, but the satisfaction of having the light off for good would be worth it.

I just hit 100k on my 2013 encore.

 

[dmeagles]

Engine light on and off for weeks with noted lack of acceleration when the engine light is on. Reliable, trustworthy mechanic diagnosed broken turbo booster. $1800 to replace. Since leaving the garage after diagnosis, five days have passed until my appointment tomorrow to have the repair done, the engine light has been off and no trouble with acceleration. Do I proceed with the repair? Is something loose rather than broken and needing to be replaced?
Thank you

 

[asdx1234]

Mine was the same. Engine light on then it would turn off the next day or couple of days. Sometimes it would be off for several days and I would think hey great but then yha back on.

 

[MaxxyJD]

Received a check engine light on my way out to go xmas shopping. Called Onstar for diagnostic and its a P0299 error ... to do with my turbo. I just got this 2017 Buick Encore in end Sept with about 80,000 km on it. How much is this going to run me...to diagnose and fix. Seems labor costs are out weighing the actual part itself now days and seems like they take longer and longer to fix. With hardly any garages open on weekends, and i have to lose a day of work to even get it checked. no one loans out cars anymore nor take less than a day to diagnose and fix...is this something i can do myself. If so what do i need to check to fix.

 

[Busted33]

Received a check engine light on my way out to go xmas shopping. Called Onstar for diagnostic and its a P0299 error ... to do with my turbo. I just got this 2017 Buick Encore in end Sept with about 80,000 km on it. How much is this going to run me...to diagnose and fix. Seems labor costs are out weighing the actual part itself now days and seems like they take longer and longer to fix. With hardly any garages open on weekends, and i have to lose a day of work to even get it checked. no one loans out cars anymore nor take less than a day to diagnose and fix...is this something i can do myself. If so what do i need to check to fix.

These problems all appear to be very similar. My daughter has a 2016 Buick
Encore with the LE2 engine. She has 47k miles and the PO299 code has started since ~April this year. It comes on, runs like shit then goes off on its own for a few days, then repeats. I took it to a local dealer while the light was on and he stated there is nothing obvious so he wanted to start with replacing the MAP sensor for $400 and see if that works. I told him I can get the sensor from Rock Auto for $32 and spend the 5 minutes to replace it myself. He said all they can do is start throwing parts at it until its fixed. So far I have replaced the MAP sensor in the intake and today I removed the front bumper to replace the Turbo boost sensor in the Intercooler outlet pipe to the intake. My plan is to remove and clean all the turbo hoses and retighten them to see if that helps. Seems like GM doesn't know how to properly diagnose these failures if the dealer response was to "throw parts at it until it gets fixed".

Not happy with GM on this one.

 

[Again]

You're on the right path. Don't change parts. Remove and clean the hoses on the intercooler since you have the bumper "OFF". You will probably find sand and grit at the bottom especially at the outlet side. Put a little bit of grease or vaseline on the "O" rings and reassemble. Do the same at the throttle body. Make sure it's tight. Also check the hose at the turbo outlet. Guaranteed you'll have a totally different Encore once done. You may also want to check how free the gate lever is, situated under the manifold shield.

 

[Busted33]

You're on the right path. Don't change parts. Remove and clean the hoses on the intercooler since you have the bumper "OFF". You will probably find sand and grit at the bottom especially at the outlet side. Put a little bit of grease or vaseline on the "O" rings and reassemble. Do the same at the throttle body. Make sure it's tight. Also check the hose at the turbo outlet. Guaranteed you'll have a totally different Encore once done. You may also want to check how free the gate lever is, situated under the manifold shield.

^^This gives me some hope. The clamps on the intercooler hoses are strange looking things. Do I need to break these off and replace with hose clamps or are these reusable? I can turn the hose relatively easy on the intercooler outlet so I am thinking it is a little too lose.

Thanks for the feedback!!

 

[Busted33]

Actually I just figured out how to remove the hoses as they have a compression style fitting with the wire retention clips (similar to what I have seen on automatic transmission coolant lines). My question is are these connections known to fail and should I replace these with some other style of clamp?

 

[Again]

I always reuse the original so far without a problem, but you could possibly have a bad one. Most important is to remove all the dirt that got caught between the bottom of the intercooler neck and the hose. This is cause by multiple freezing and thawing cycles where frost opens the gap and lets dirt accumulate. All you need a is a grain of sand and you're leaking like a basket. Maybe interchange the clamps if they are the same size. Add some plastic safe grease, this will delay water from getting in there and make a better seal.