2020 GMC Terrain Engine Problems

Catastrophic engine failure; no warning lights,etc. took place on or about end of January 2026. Car completely died and would not start. Car towed to dealer (GMC Blaise Alexander, Hazleton, PA) Vehicle inspected by dealer master mechanic and others. Engine completely disassembled. Unable to repair. No warnings, lamps, messages or other symptoms prior to failure. Tremendous expense had to be incurred by us over this incident. We had to purchase a new car. Terrain had been meticulously maintained by dealer since purchase. We still had over one year of payments remaining. Expected car to last closer to 200,000 miles. A new engine could have been installed, but cost was too expensive. We lost all of our equity in the vehicle.

From a complete stop my car refused to accelerate no matter how much I pushed the gas pedal. I was pulling into traffic and was on a hill so my car rolled forward naturally into the road but would not respond to the gas pedal. The RPMs didn't move, the car had power, I tried putting it in reverse and then back into drive. Nothing worked for a solid 2 minutes at least. Then all of a sudden it registered and worked. I was almost t-boned from a car coming through the curve but luckily, they were able to go around me in time. This put me and my small daughter at risk of being severely injured from a malfunction that I can't recreate to show the technicians. Since this incident, it has happened several times randomly. Sometimes I'm at a red light, or backing out of a parking spot, or pulling out into traffic. When it happens, there are no codes thrown to show any engine malfunctions, but it WILL NOT MOVE! I've noticed more and more the lack of power when driving. Almost as if the transmission is slipping or losing power as well. I bought the car new, only have 38K miles on it, and service it every 5k miles at a GMC dealership. This is going to end up killing someone. The mechanic told me to trade it in, but I just paid it off and it's only 5 years old. There are multiple complaints about this same thing happening with tons of Terrains and there isn't a recall yet.

First problem was when the ac went out which affected the starter 2 weeks after that while I was driving something popped underneath the vehicle the vehicle completely stopped working when I checked underneath the vehicle there was leak ish a broken crankshaft car would not turn back on….

While my wife was driving on [XXX] speed (60 –70 mph), the engine suddenly seized without warning. This created a dangerous situation, especially at that speed. Upon inspection, it was confirmed that a camshaft end cap detached, causing catastrophic internal engine damage. I believe this may be due to a manufacturing defect or insufficient part durability, and poses a serious safety risk to myself and other drivers. Please investigate this issue for broader safety concerns and potential recalls, especially if other owners report similar failures. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The contact owns a 2020 GMC Terrain. The contact stated while driving 45 MPH, the vehicle inadvertently lost motive power. The contact was able to pull over to the shoulder of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was towed to the dealer, who determined that the engine had seized. The contact was informed that the engine needed to be replaced. The vehicle was repaired, but the failure reoccurred. The vehicle was again towed to the dealer, who again diagnosed a failure with the engine. The vehicle was not repaired. After investigating the failure, the contact related the failure to NHTSA Campaign Number: 25V274000 (Engine and Engine Cooling); but the VIN was not included. The manufacturer was notified of the failure, a case was opened, and the contact was referred to the NHTSA Hotline for assistance. The failure mileage was unknown.

This message concerns a persistent engine light that activates and generates engine code P0299, indicating an engine underboost issue. There have been several occasions where I am driving over 55mph on the highway and my 2020 Terrain SLT fails to pick up speed over 60mph in traffic. I took it to my GMC dealer earlier this year for them to diagnose, and they discovered that the charge air cooler tube had collected moisture. Once that was fixed, the vehicle was fine for about a month when the same thing happened. I took it to another GMC dealer and found that the turbocharger wastegate actuator had to be replaced. Once replaced, I had no problems until it began to get cold where I live. Now the vehicle is doing the same thing. Now what happens is the engine light will come on and give the engine underboost message but goes away after a week of driving. I have taken it to 2 dealers for diagnosis, only for the engine light to disappear before they can figure out what the problem is now. This continues to be an issue, as I frequently drive on the highway over 55mph for work, errands, etc., and presents a potential hazard if I have to pick up speed and can't on a major highway.

Car was very well maintained 2020 GMC Terrain, no warnings prior to the issues. Car started shaking while driving, would not allow me to accelerate without chugging, multiple lights came on including flashing check engine light. Somehow the whole motor and engine needs replaced.

The contact owns a 2020 GMC Terrain. The contact stated that while his daughter was driving at an undisclosed speed, an unknown warning light displayed on the instrument panel. The vehicle started losing motive power and the vehicle shut off while in a parking lot. The contact was notified of the failure and a tow truck was contacted. While waiting for the tow truck to arrive, the contact's daughter was able to restart the vehicle and drive to the residence. The dealer was notified of the failure the following day and the vehicle was towed to the dealer. The contact stated that a diagnostic test was performed, and the contact was informed that metal shavings were found inside the engine and the vehicle was diagnosed with engine failure. The manufacturer was notified of the failure but offered no assistance. The contact was referred to the NHTSA Hotline to report the failure. The vehicle was not repaired. The failure mileage was approximately 67,000.

The vacuum pump locked up and sheered off the end of the cam shaft and made the cam skip timing and destroyed the motor. While driving no check engine likes till after i lost power. Luckly i was able to roll to a stop The pumps have been a problem the car is only 4yrs old and has 71000 miles.

This GMC I just purchased in October 22 2022 and have been complaining since December 9,2022 the vehicle emergency braking will activate when I'm driving down the interstate or local roads I could be doing 70 and brakes will just lock up throwing me and my son forward , this has happened 4x , Gas Pedal when taking off at red light or pulling out the vehicle is hesitant and will not go this has happened on 3 different occasions. I called roadside on star they said there is a problem with the on star saftey feature will not work properly this was towed 2x to different shops, Also while driving this vehicle it will just ingage itself in park while driving called on star they did diagnostic there was all kinds of Coded for Transmission and Engine as well as Emissions this vehicle is a safety hazard.. And I have tried to take back to dealership where I purchased they keep making excuses to not see this CPO with lifetime Warranty and still under warranty from GMC vechle Mileage was at 29k when problems stared vehicle only has 31k I can't drive this vehicle due to my son's and myself along with others saftey this is ridiculous and also GMC just informed me the Vin # they have for my vehicle and whats on it are two different numbers! Yet nothing is being done I'm paying for a vehicle that I can't drive I have proof GMC knows about the fraud from dealership but GMC says its a sales thing This vehicle has been flooded two mechanics have confirmed and GMC is aware so why not do something I don't know exactly the history and GMC doesn't either please someone contact me GMC this is crazy and you know it's a safety issue with this 2020 GMC Terrain you even said so

The contact's friend's son owns a 2020 GMC Terrain. The contact stated that while her friend was driving at an undisclosed speed, the brake pedal went to the floorboard while depressed. The brakes failed to immediately stop the vehicle. Additionally, the vehicle made grinding sounds while driving. The vehicle was taken to the dealer, where the vacuum pump, exhaust camshaft, and valve cover gasket were replaced; however, the vehicle lost motive power while driving. The vehicle was towed back to the dealer, where it was determined that the engine needed to be replaced. The vehicle was not repaired. The manufacturer was made aware of the failure and informed the contact that there was no recall associated with the VIN. The failure mileage was approximately 48,552. The contact stated that additionally, the check engine light came on without cause. The contact is unsure why that is because a diagnostic test had just been performed.

I just purchased this vehicle about 2 weeks ago, and was driving through the fog/cold weather and my check engine light came on. Went to O'Reillys and had them check the code. Came up as P0299 (My car was telling me that the engine power was decreased) I had a loss of power I could feel while driving as well. The code said turbo under boost. After I got back into town and the weather was warmer and no fog was present, the turbo started working again. I brought my vehicle into the dealer where I bought it from and they took it to their mechanic and supposedly performed an "update". I will see if I continue to have the same issue in cold weather as I live in Idaho and go to the mountains often.

The contact owns a 2020 GMC Terrain. The contact stated that while driving 50 MPH, the vehicle lost braking power. The driver was able to pull over safely. There were no warning lights illuminated. The vehicle was towed to the local dealer, where it was diagnosed that the vacuum pump had shattered. The vehicle was repaired, but the failure recurred. The contact reached out to a GMC engineer, who informed the contact that the failure was due to the camshaft reluctor. While driving, the vehicle lost engine power. The vehicle was towed to the same local dealer, where it was diagnosed that the throttle body needed to be replaced. The vehicle was repaired, but the failure recurred. The vehicle was towed to the local dealer, where it was diagnosed that the turbo code had a mass air flow sensor failure. The vehicle was repaired. While driving at an undisclosed speed, the check engine warning light illuminated, and the reduced engine power message was displayed. There was blue smoke detected from the exhaust. The vehicle was towed to an independent mechanic, who informed the contact that the throttle had failed. The vehicle was towed to another local dealer, Power GMC Chevrolet of Newport (1422 N Coast Hwy, Newport, OR 97365) where it was diagnosed that the air pipe charge and air cooler needed to be replaced. The vehicle was repaired. The manufacturer was contacted and referred the contact to the local dealer. The failure mileage was approximately 50,000.

The engine cutoff while driving through a major intersection in 3/2022 with no warning lamps, messages or other symptoms of the problem prior to the failure. Dealership replaced the fuel pump module. Subsequently, the engine cutoff while driving in 5/2023. Dealership replaced the fuel pump module. Each of these occurrences placed my life, my passengers life and the lives of others on the road in danger as an accident could have resulted if I was not able to coast out of harms way. GMC has an existing recall on the fuel pump module for 2021 - 2022 Chevrolet Equinox and 2022 GMC Terrain vehicles. Why did this happen a second time after replacing the fuel pump module? Are they using a module included in the recall? I was charged $ 591 dollars for the repair in 3/2022 and no charge in 5/2023 as they stated it must have been a faulty module. I have no confidence in my safety and the module they used in 5/2023 is not faulty.

The engine will never go into 9th gear! What's the point of GMC doing a 9 gear transmission to help with fuel, if it never actually goes into the 9th gear?

loss of oil due to engine defect and need new engine. engine and car at dealership. engine has not been torn apart to find cause. occupants could have died because of engine stoppage... GM wants owner to pay over 15,000 for new engine and instillation. car under new car warranty has 24211 miles. no early warning lights of low oil.... Owner took car in immediately when warning lights appeared 9-27-21 and GMC dealership improperly serviced . on 10-14-21 same warning lights reappeared and taken immediately to same close dealership. Now told new engine needed.