GMC Terrain Complaints (2019)

187 consumer complaints on file.

#11773185October 23, 2026
POWER TRAIN
Transmission leak caused but start and stop accumulator
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11770963October 13, 2026
ENGINE, SERVICE BRAKES, POWER TRAIN
VIN: [XXX] Mileage: Approximately 103,576 Incident location: [XXX] Safety Complaint: While my wife was driving our 2019 GMC Terrain into a shopping center parking lot, the vehicle suddenly experienced a severe loss of braking assistance. The brake pedal became extremely stiff and difficult to depress, and she was barely able to slow the vehicle. This occurred unexpectedly while the engine continued running, creating a serious risk of a collision. Following the incident, I inspected the vehicle using an OBD-II diagnostic scanner, which identified diagnostic trouble code P0016 (crankshaft/camshaft position correlation). The vehicle also displayed an oil-pressure warning. We subsequently had the vehicle inspected by John's Automotive Care in [XXX] on XXX. During the inspection, the technician discovered a significant amount of metallic debris in the engine oil. The repair facility suspects a mechanical failure of the engine-driven brake vacuum pump, potentially resulting in damage to the engine and lubrication system. The repair facility recommended replacing the mechanical vacuum pump and engine oil-pressure switch and performing an oil change. However, the service representative explained that these repairs would not guarantee the engine's continued reliability because the engine was compromised and could fail at any time. We are extremely concerned that a failure involving the brake vacuum pump could cause sudden loss of braking assistance without adequate warning, potentially resulting in a serious accident. We request that NHTSA investigate whether this failure represents a safety-related defect affecting the 2019 GMC Terrain and other vehicles equipped with similar engine-driven brake vacuum pump systems. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11766640September 24, 2026
SERVICE BRAKES, ELECTRICAL SYSTEM, ENGINE
While driving on an interstate, vehicle became sluggish when accelerating. Took off on exit, engine was reduced to 50% power, attempted to drive to large parking lot, lost brakes, got the vehicle stopped in an intersection, would not shut off, go into neutral. Finally shut off, had to call tow truck, holding up traffic in a busy intersection. Was told it would be just $900 to fully diagnose problem, but it appeared the vacuum pump failed, threw broken metal into engine and now will have to be replaced at my cost. NO advanced warning of any type of problem, no warning lights, etc.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11766497September 23, 2026
POWER TRAIN
The contact owns a 2019 GMC Terrain. The contact stated that after pulling into a parking lot, the vehicle failed to shift into park. The vehicle was towed to a dealer where the contact was informed that three fault codes were found. The dealer informed the contact that the transmission needed to be disassembled for a full diagnostic test. The vehicle was not repaired. The vehicle was scheduled for the transmission to be disassembled for the diagnostic test. The failure mileage was approximately 60,000.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11764910September 17, 2026
SERVICE BRAKES, ENGINE
On 9/15/2026, my wife drove her car, a 2019 GMC Terrain, to a doctor's appointment. She reported no known issues with the way the car operated during her drive nor had she or I experienced issues prior to this event. After she finished her appointment, she attempted to start her car and was unable to get the car to start. She also noticed that the brake pedal was stiff and hard to depress. When I arrived, I tried to assist her, thinking that an electrical issue was the fault. However, I was still unable to start the car and I had to have it towed after I couldn't start her car. I had it towed to a mechanic who initially thought the car had a bad starter, however, after attempting to manually turn the engine, he found that the engine was completely seized. He also confirmed that the oil in the car appeared to be without fragments in it and that the oil level was adequate for normal operation. This car is only seven years old, has had routine maintenance, and is about 60 miles over 100,000. No prior issues were noticed before this happened. I'm currently waiting on an engine for the car so we can start using it again.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11762176September 4, 2026
SERVICE BRAKES, ENGINE
While driving my 2019 GMC Terrain with three children as passengers, the vehicle developed a braking/engine problem. The brake pedal became very hard, and the vehicle subsequently became undrivable and would not start. I received no advance warning through the GMC app indicating that the vacuum pump was failing. The vehicle was towed to a GMC dealership. The dealership diagnosed a failed vacuum pump and advised that the engine requires replacement, with an estimate of approximately $11,238. I purchased this vehicle new. I am very concerned that a vacuum-pump failure can result in reduced brake assist/increased brake-pedal effort and major engine damage without adequate advance warning. Three children were in the vehicle when this occurred, and the sudden change in braking created a serious safety concern for everyone in the vehicle. The vehicle is currently at the GMC dealership. I have requested that relevant parts be preserved and am requesting GM Policy Assistance with the repair.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11758591August 21, 2026
SERVICE BRAKES, ENGINE, ELECTRICAL SYSTEM
On Saturday, August 15th we were driving on the freeway when with no warning the check engine light came on and the vehicle began to run poorly, and then the vehicle lost electrical power and it became difficult to steer and the brake pedal became stiff, making it difficult to stop and pull over. The vehicle would not start on command but kept running very poorly, it also became impossible to shut the vehicle off until it seized. It was later towed to a local repair shop, and today, Friday August 21st the shop confirmed that the vacuum pump on the brake assist failed and it would need a total engine replacement.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11758661August 21, 2026
VISIBILITY/WIPER, STRUCTURE:BODY
This is the second time I have noticed storm heavy rain that my car is taken on water. We had an extremely heavy rain in June and no windows was left open. I did not know water had gotten into my car for an entire month when I heard a solution sale when I came to a break, what I did realize is that there was condensation buildup is inside of my car, but it was not sure why. After searching, I was able to locate and discover thatI had at least 3 inches of water standing water in my spare tire, section of my trunk. There was also an extreme amount of water on my floors in the back row once I took out my mats, I found there to be mold back there.Still unsure of how t the water got into the car I used my shop vac to suck out the water. We just had an extreme amount of heavy rain again. We are now in August. We just had extremely heavy amounts of rain and once again there’s water in the well trunk of my car where the spare tire is. I actually made sure to sit outside in my car during this heavy rain storm to see where the water was coming from. It appears that the water is coming from the sunroof, which then leaks to the back on the right hand side where the outlet socket is. I watched it dripped down into the back of the trunk into the spare tire well. I do not understand why this issue has not triggered a a recall yet as I’m noticing this is not just with my car. This is apparently the sixth or seventh car that has experienced this issue and GMC has yet to do a recall on it. This is very alarming and concerning God forbid I’m driving to work or I have one of my children in the car during a heavy rain storm and it hits the electrical wires or electrical panel with something else bad happens.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11757612August 18, 2026
SERVICE BRAKES, ENGINE
The car’s brakes hardened on the highway, posing a life-threatening danger, right before the engine died. Following a tow to the dealership’s service center, an initial inspection revealed a broken vacuum pump and broken camshaft. The dealership stated that there was evidence that camshaft debris may be scattered throughout the engine. No further inspection has been done at this time due to the probability of major engine damage and/or potential repairs.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11755772August 9, 2026
SERVICE BRAKES, ENGINE
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."
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11748359July 5, 2026
ENGINE, UNKNOWN OR OTHER
While driving the vehicle became extremely difficult to stop I was advised that the Vacuum booster pump was broken and it needed to be replaced. This was first completed 09/24/25 by Gateway tire and service center. I was advised that there was a service bulletin for the issue. Then I have had the same thing happen and I returned the vehicle to the same repair shop and I was advised that the Vacuum booster pump was broken and it caused the exhaust camshaft to break, as well as the timing was out. The shop had to replace several things in order to repair and I was responsible for the cost. There was no warning before either of the incidents.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11748117July 3, 2026
POWER TRAIN
No engine lights are on. When at stops it starts chugging and when I accelerate sometimes it does not go like it should. It idles high and feels like it is slipping. I have almost been hit in the rear several times when this happens. One lady did rear end me but the damage was so little that I did not call the cops. This vehicle has not been inspected and it is available for inspection at any time.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11743318June 10, 2026
ENGINE, POWER TRAIN
The turbo went completely out at around 105k miles while I was driving to work. I had to coast into a repair shop because it was smoking and wouldn’t go over 20mph and then have it towed to the place that repaired it. Since then, the transmission is having trouble shifting gears. The car struggles to accelerate and I have to go abnormally slow after coming to a complete stop in order for the car to get into gear. The onstar diagnostic says everything is fine but it is clearly not fine.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11738911May 19, 2026
UNKNOWN OR OTHER
My 2019 GMC Terrain has a faulty back up camera system. It shows a blue screen that says Service rear view camera system, This has been a faulty system for years until it finally stopped working completely. I have researched the issue and have discovered this is a known problem. There was a Service Bulletin 19-NA-076 dated April of 2019. Why has there not been a recall for this safety issue?
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11737591May 13, 2026
ENGINE, SERVICE BRAKES, HYDRAULIC:POWER ASSIST:VACUUM
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11735393May 3, 2026
VISIBILITY/WIPER
I got into my car to head to the store today. Upon closing drivers door I heard a muffled sounding pop. As I looked around I noticed back windshield looked “weird”. Got out and walked around the back to see it completely shattered. It just exploded and every inch has a crack or chip, even all asking the edges of the glass. I lifted the tail gate to see if a rock was thrown by chance and a chunk fell into the car. No rock was found. It simply shattered. The temp today was low 60’s on May 3rd, 2026 here in Ohio.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11733476April 23, 2026
SERVICE BRAKES, ELECTRICAL SYSTEM, FUEL/PROPULSION SYSTEM
My cars breaks failed by a vacuum pump failer and I almost died on the a hill going home
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11732575April 20, 2026
ENGINE
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.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11731108April 14, 2026
UNKNOWN OR OTHER
This is the 4th time my vacuum pump has “broke” my brakes become hard and stiff and my brake assist light comes on. It happens EVERY winter when it drops below freezing. This is the second time this winter it has broke and now my check engine light is on. It is not cheap to fix and a major safety issue. Would like to add I was only backing out of my drive way this last time it happened. I was going maybe 5-10 mph.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0
#11727730March 28, 2026
SERVICE BRAKES
Brake assist light came on and brake pedal became stiff/hard to push. Vehicle struggled to brake. Replaced brake pads and checked brake fluid. Brakes still inoperable. Check engine light came on for vacuum pump. When replacing pump, metal shards and pieces were falling out when original was removed. Once replacement was installed vehicle began hesitating to start and run.
Crash:
No
Fire:
No
Injuries:
0
Deaths:
0

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