2019 GMC Terrain: sudden loss of power

Filed Aug 9, 2026 · Brakes, Engine · MI

While driving my 2019 GMC Terrain on local roads, the vehicle suffered a sudden and complete failure of the braking system. The brake pedal became extremely hard to press, and the dashboard displayed a critical error message stating 'Engine Power is Reduced.' during this frightening safety incident i felt lucky to bring the car to a stop without an accident. The vehicle had to be flatbed towed to a repair facility. This sudden loss of power braking is a known, documented defect matching the engine-driven brake vacuum pump failures currently subject to federal class-action litigation (Thieme v. General Motors). I am requesting a formal safety investigation into why the GMC Terrain was excluded from previous GM vacuum pump recalls despite posing an identical, life-threatening risk to occupants."

Filed May 13, 2026 · Brakes, Engine · 76,000 miles · MI

The contact owns a 2019 GMC Terrain. The contact stated that while stopped and attempting to turn to exit a highway ramp, he observed a loud banging noise emanating from the engine compartment. An "engine reduced power" message appeared. The vehicle then went into limp mode, and when the brake pedal was depressed, it was stiff as a rock. The vehicle coasted while he continued attempting to depress the brake pedal, and it eventually slowed down. The vehicle was steered to the side of the road and turned off. When the vehicle was turned back on and he attempted to depress the accelerator pedal, the vehicle did not accelerate. The vehicle was taken to his mother's residence approximately 100 miles away in limp mode and parked. The vehicle was not diagnosed or repaired. The contact stated that his brother, during an inspection of the vehicle, removed the vacuum pump and noticed that it was broken with numerous pieces that had gone into the engine. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 76,000.

Filed Apr 20, 2026 · Engine · ME

Engine breakdown 1.5turbo in 11/28/25 with 16820 miles on it. It is not available I heard a bang and smoke out of back lost power while driving on the high way damage was confirmed buy a dealer goodwin chevrolet in brunswick me yes buy gm dealer. No there were no warning lamps or other symptoms before failure. Car was check on 3/30/2023 at 10383 miles for shaking and losing power.car did come out it took it to lee gm dealer in auburn me could not duplicate problem.

Filed Nov 11, 2025 · Electrical, Engine · MA

Vehicle has had check engine light and engine reduced power flicking on and off for months, randomly reducing power on highway or nearly causing accidents. Brought car to GMC dealer, they said it was underboost code and needed new turbo. Paid over 7,000$ for repair. Next morning, same issue still was happening. I believe my vehicle has EMISSIONS recall issue “N192271200 Charge Air Cooler Disconnect at Throttle Body” but GM has not properly attached my vin number for this recall repair. I have poured thousands into repairs out of pocket and the same issue still persists. I believe strongly the recall emission issue is the problem and should be on my vin. Vehicle has been to dealer 3 times in the past 2 weeks, issue has not been fixed. Improperly diagnosed, random repairs made not fixing actual issue.

Filed Jul 8, 2025 · Brakes, Transmission · PA

Accelerating from a stopped position into a busy intersection heard a loud clunk come from engine bay resulting in immediate "Reduced engine power" warning and stall condition. Was able to push vehicle onto the side of the road. Engine would not restart and a tow truck was called. Vehicle towed to local dealership who discovered that Vacuum Pump had failed resulting in sheering off of the exhaust camshaft. Dealers recommended fix was to replace vacuum pump and camshaft at around $4,000 but could not guarantee no debris had gotten into valve body resulting in engine failure so stated they could replace with used engine for 8500. Second vacuum pump to blow on this vehicle, first at 35k miles and replaced under warranty, this incident at just under 80k miles. Could not afford repairs and vehicle has sat for nearly 2.5 years. Contacted GM many times over that time period to get no assistance, only the offer of a small discount on a new vehicle. This incident could have proven fatal if happening at highway speeds since it stalls engine out and makes braking nearly impossible. Both GM and the NHSTA have really flunked on this one, should have been recalled during first complaints in 2020. I will continue to file complaints here on NHSTA and with GM until the cows come home.

Filed Apr 22, 2024 · Brakes, Engine · MA

Vaccumm pump failed and broke metal shavings off into engine resulting in “engine failure”. I was driving on the highway with my 6 year old child in back seat, car completely shut down and shot a “reduced engine power” message while on a busy on ramp heading onto highway. This created an extremely dangerous situation for myself and my child as many cars almost smashed into the vehicle. I’ve seen many other complaints of this happening, the same exact parts and issue happened to the Chevy Equinox which resulted in a recall but they have yet to recall the Terrain, which is having the exact same issue. I am a single mother, with 20k still on my loan. This mistake made by gmc has now costed me over 5,000$ out of pocket for something that is not my fault and completely out of my control. Even after all of the money poured into this repair, I still feel unsafe in my own vehicle as there is no guarantee this issue will not happen again. I’ve kept up on all oil changes and maintenance of my vehicle. The issue was confirmed by a GMC mechanic which cost 500$ out of pocket for diagnosis as well. I also had to spend 1000$ on a rental out of pocket because of this. I have seen many others complaints of the same issue happening to their GMC terrain and am appalled no recall has been discussed after the reaccuring issue. I should not be having to pay out of pocket for an issue GMC has yet to fix or issue a recall on. I had to miss days of work, and it really was a huge inconvenience. I do not feel safe in my own vehicle even after the repair, cause I have no guarantee this won’t just happen all over again.

Filed Apr 22, 2024 · Transmission · TX

First the car started jerking while drive over 50mph, next day driving down the street and the car shut off, stating loss of power. I replaced the battery, it was giving battery low codes, only to get a certified mechanic say the timing chain was out. Just purchased the car in March 2022.

Filed Mar 29, 2024 · Brakes, Engine · PA

While driving on 95, I lost all engine and power breaks with no warning. A message came up on my dash stating that I had lost engine power. Fortunately an exit was up ahead so I was able to get there and coast down the ramp. I attempted to make a right turn to get out of the way but ran out of momentum. Dealership stated my vacuum break pump failed and went into the cam shaft. They had to replace those and the solenoid actuator and value. They also conducted an oil change. I received it back yesterday, started the car today and the check engine light was on. They found more debris and replaced another point and said if the light comes on again it's the timing chains in the engine. I went out leave and the check engine light was on. They are now keeping it to repair the timing chains. I am fighting with GM to cover the expenses since I see this is an issue in previous models/years of GMC and Chevy vehicles.

Filed Aug 18, 2022 · Brakes, Engine · MI

Our son and two daughters were driving on the highway at approximately 70mph when a message came up to say the engine was in "Reduced Engine Power". Although nothing seemed to change. The instruction for such and error message is to "get vehicle to a dealership within the next day." So they slowed to 60mph and continued on their way. About 8-10 minutes later another message popped up that said "Service Brake Assist", at which point they immediately tested the brakes and they worked. But 2-5 minutes later they tested the brakes again and the brakes had completely failed! Zero brakes on the highway! No matter how hard the driver pushed the brake pedal there was 0.0% response. So luckily they were able to coast down to about 10 mph with hazard lights on. But at that point they lost everything. No power steering, no engine, and zero brakes. Thank the lord that they were able to have enough room to slow down and get over to a shoulder prior to the loss of power steering and that they had enough room to coast to a stop. Please help, as we were extraordinarily lucky that day that 3 of our children were able to walk away from such a catastrophic vehicle failure. I just do not want that to happen to anyone else.

Filed Jul 10, 2021 · Electrical, Engine · MI

*Check engine light on, Reduced Power Light is on, and Vehicle is surging up and down. *Driving on highway and Engine power is reduced, cars behind me honked until I could get over into the right lane because I was losing power. *Yes, confirmed by LaFontaine of Ann Arbor, MI *Yes, inspected by LaFontaine of Ann Arbor MI Customer states check engine light on, reduced power light and the vehicle did have reduced power. Vehicle is surging up and down at an idel. GM assistance, submit for DMA approval to deviate on PET per Scott S DMA. N/C to customer per DMA, If an FSE is needed please submit request. Found air duct not connected to throttle body and throttle body is cause. Inspected and found air duct loose on throttle body. inspected to find throttle body edge is wore and is cause. removed and replaced throttle body to address fail code P0101. 4021510 0.8 and add 1.0 diag *yes, Engine Power is Reduced light and Engine light was on

Filed Aug 19, 2019 · Acceleration, Transmission · 17,000 miles · TX

Tl* the contact owns a 2019 gmc terrain. While driving approximately 40-70 MPH, the vehicle lost power and independently decelerated. The vehicle was taken to shamaley buick gmc (located at 955 crockett st, el paso, tx 79922, (915) 231-4000) where it was diagnosed that the transmission needed to be repaired and the power train control module needed to be updated. The vehicle was repaired; however, the failure recurred. The contact stated that the vehicle experienced the failure on four separate occasions. The manufacturer was notified of the failure and provided case number: 95389790118. The approximate failure mileage was 17,000. The VIN was invalid.

Filed Jun 12, 2019 · Acceleration, Engine · 11,000 miles · IL

I purchased a 2019 gmc terrain VIN: [xxx] on jan 17, 2019 at rizza buick gmc 8415 w. 159th street, tinley park il, 60487, on january 17, 2019. This was my first brand new car and I was excited. I traded in a 2014 gmc terrain in the process, knowing I would be upside down on the loan. I had the first service done on april 23, 2019 at said dealership. At that visit I explained that I was hearing a noise on the passenger side vent even when the HVAC was not running. I was told nothing was detected and my vehicle was fine on may 24, 2019, I drove my vehicle to memphis tennessee with my family for memorial day. On may 25, 2019 the check engine light came on, I was losing power to the engine. That same night customer service towed my vehicle to sunrise chevrolet buick gmc, 1800 covington pike memphis, tennessee 38128, a nearby gmc dealership and set up a rental car in the area for me to drive. Because it was the holiday, enterprise was closed, and I had no vehicle to drive for two days. This was an inconvenience to me and my family, I had to alter my trip plans that were made back in february 2019. On may 27, 2019 I was told by [xxx] the technician at sunrise chevrolet that air box tube was loose and not properly installed and could have been done during my service I had done april 23rd. I was assured everything was okay and I was good to go. On may 31, while traveling back home the check engine light came on again. Same message on the dash and it was raining at 3am. I was close to home and was able to make it to the dealership that I purchased it from. My vehicle has been in service since may 31, 2019 and I am just finding out that I have a part that is on national back order. I am not satisfied with my experience an I am reaching out to you to resolve this matter. Information redacted pursuant to the freedom of information act (foia), 5 u.s.c. 552(b)(6).