GMC Terrain engine failure problems

Filed Oct 27, 2026 · Brakes · 90,000 miles · OH

The contact owns a 2020 GMC Terrain. The contact stated that while driving 45 MPH, the accelerator pedal was depressed; however, the vehicle failed to accelerate as intended. The transmission then sputtered. The vehicle was uncontrollable, the brake pedal was depressed; however, the vehicle failed to stop as intended. The vehicle accelerated and drove through an intersection and the engine seized. The vehicle was towed to an independent mechanic where it was diagnosed with vacuum pump failure. The contact was informed that the vacuum pump needed to be replaced. The contact was advised to contact the dealer. The dealer was contacted and made aware of the failure. The contact was advised to contact the manufacturer. The manufacturer was contacted and made aware of the failure. The contact was advised to contact the federal safety agency Hotline to report the failure. The failure mileage was approximately 90,000.

Filed Oct 14, 2026 · Brakes, Engine · IN

On XXX while driving my 2018 GMC Terrain SLE 1.5L turbo on the highway at approximately 70 MPH near [XXX]. I experienced a sudden loss of power brake assist without any prior dashboard warning lights or messages. I was traveling with children to [XXX] for a youth wrestling tournament, approximately 5 hours from my residence. The brake pedal became extremely hard to press, requiring excessive force to slow the vehicle while traveling at highway speeds. I was transporting children at the time, creating a serious safety concern. Because I was away from home and needed to get the children to their scheduled wrestling weigh-ins, I arranged alternative transportation through Enterprise. I was unable to have my vehicle inspected by a GMC dealership until XXX, after returning home. At approximately 93,614 miles, Ed Martin Buick GMC diagnosed an internally failed, engine-driven brake vacuum pump. The service advisor confirmed in writing that the pump had come apart internally and explained that a seized pump can strip the exhaust camshaft gear. The dealership documented missing metal material from the vacuum pump and camshaft gear, raising concerns about metal debris entering the engine. Diagnostic trouble codes included P0014, P0017, and P0556. The dealership estimated repairs at $5,960.79 but advised that the proposed repairs might not remove all internal metal debris. The service advisor stated that replacing the engine would be the only way to guarantee complete debris removal. GM has published technical service information, including PIP5835 and Bulletin 21-NA-268, addressing similar vacuum pump failures and associated damage. The vehicle remains unrepaired. I am reporting this incident because an unexpected loss of power brake assist at highway speeds, without advance warning, creates a significant collision risk for drivers, passengers, and other motorists. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Sep 17, 2026 · Brakes, Engine · KY

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.

Filed Sep 11, 2026 · Engine · TX

Vehicle Information:Year/Make/Model: 2021 GMC TerrainEngine Type: 1.5L Turbocharged EngineCurrent Mileage: 155,000 miles [1]Description of Safety Defect:I am writing to report a severe, sudden engine and turbocharger failure on my 2021 GMC Terrain that presents an extreme, life-threatening safety hazard. While operating the vehicle in active traffic, the engine began flashing a severe dashboard warning reading "Stop Now Danger" (accompanied by low oil pressure alerts) before suffering an immediate, catastrophic loss of all motive power. 2-This unexpected stalling leaves the driver completely stranded on active roadways without warning, drastically expanding the risk of a high-speed rear-end collision. A mechanic has inspected the vehicle and confirmed that both the engine assembly and the turbocharger require full replacement, with a repair estimate totaling $12,000. General Motors is currently facing legal actions regarding defective, camshaft-driven mechanical vacuum pumps and PCV configurations on these 2018–2022 1.5L engines defects known to fracture, send metal fragments violently into the engine top, and trigger immediate engine failure and turbocharger destruction. Despite these severe risks, GMC has refused to provide any goodwill assistance or repairs because the vehicle is outside warranty. I request that the federal safety agency immediately investigate the engine-destroying defects inherent to the 2018–2022 GMC Terrain line to protect consumers from catastrophic highway power failure.

Filed Aug 21, 2026 · Brakes, Electrical · PA

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.

Filed Aug 18, 2026 · Brakes, Engine · NJ

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.

Filed Aug 14, 2026 · Engine · WI

The timing chain snapped and caused the engine to seize on our 2016 GMC Terrain 2.4L SLC-1 SUV/Truck. Since this has occurred multiple times on the 2.4L engines in this model from 2012 - 2016, we believe that there should be a recall as this issue could cause a major accident if the timing chain snaps or breaks while traveling. It had 101000 miles on it when we bought it used from Klein Automotive, on April 12, 2024. We have only had it for 2 years and 4 months and kept it in good repair. We took it in for its oil change, brought it home, went to dinner 4 days after and the very next day it wouldn't start. We thought it was most likely the starter/solenoid, but the mechanic said those were both fine and that's when we got the bad news that the motor was shot because the timing chain broke which caused some engine rods to break. The GMC dealer, in Marinette, WI, we brought our used 2016 GMC Terrain to, told us that the timing chain stretched and broke the rods in the engine and therefore both the timing chain and engine need to be replaced. The check engine light was turning on all of the time, and we were told that it was because it needed the 88 fuels (medium grade). As long as we put in the 88, the light check engine light stayed off. We believe there should be a recall for the 2012 - 2016 GMC Terrain SLC-1 2.4L timing chain and engine. We also need assistance with the cost of the repairs because I'm on a limited income and cannot afford the $10,000 cost of getting this repaired, while I still owe $7800 on it.

Filed Jul 23, 2026 · Brakes, Engine · NH

Vacuum pump failure causing sudden and unexpected hard brake pedal and loss of braking coming off the highway. Ended up catastrophic engine failure. This is the SECOND incident with this vehicle of the exact same problem. GMC refuses to address this issue and continues to risk the lives of their customers.

Filed Jul 22, 2026 · Engine · IL

I am submitting this complaint regarding the engine timing chain failure in my 2015 GMC Terrain because I believe it presents a serious safety hazard. Before the failure, the vehicle began experiencing intermittent symptoms, including engine jerking, shaking, rough operation, abnormal engine noises, and an intermittent check engine light. While driving on the highway, the engine timing chain failed, causing the vehicle to suddenly lose power. I was traveling at highway speed and had to safely maneuver the vehicle out of traffic. The unexpected loss of power placed me and other motorists at risk of a collision because I could no longer safely maintain the flow of traffic. The vehicle was towed to an independent repair facility, where the engine was diagnosed with a timing chain failure. I was informed that the engine had sustained significant damage and required replacement. After purchasing and installing a replacement engine, that engine also began exhibiting timing chain-related symptoms immediately after installation, including abnormal rattling noises and unstable engine operation, resulting in additional repairs and the vehicle remaining unsafe to drive. I am concerned that timing chain failures in this model can occur without sufficient warning and can cause a sudden loss of engine power while the vehicle is being driven. A sudden engine failure at highway speeds creates a significant risk of a crash, injury, or death. I am requesting that this issue be investigated to determine whether it represents a safety-related defect affecting other 2015 GMC Terrain vehicles.

Filed Jun 6, 2026 · Brakes, Engine · NH

I am a [XXX] resident. While commuting to work in [XXX], my GMC Terrain experienced a sudden, catastrophic failure of the brake vacuum pump while traveling at highway speeds. When I attempted to slow down for the exit, the brake pedal instantly became extremely stiff and nearly impossible to depress. I realized I had suffered an absolute loss of power braking assist. To avoid a high-speed collision with heavy highway traffic, I was forced to deliberately steer onto the roadside rumble strips, relying on tire friction to slow the vehicle down. This severe near-miss left me terrified and distraught. Because the shoulder was narrow, my disabled vehicle was left partially protruding into the active roadway. Passing cars sped by so close that my vehicle was violently rocking, creating an incredibly unsafe situation. I was forced to call the State Police for emergency assistance. They dispatched a trooper and a tow truck to remove me and the vehicle safely from the highway. The vehicle was towed to a mechanic in Massachusetts. The mechanic discovered that the vacuum pump had internally exploded. This explosion sent catastrophic metal shards and debris directly into the engines oil galleys and oiling system. While the vehicle has 121,776 miles, this is not a normal wear-and-tear component failure. The brake vacuum pump suffered a catastrophic internal mechanical explosion at highway speeds, completely eliminating my ability to stop the vehicle. A mechanical component failure should never cause an immediate, life-threatening loss of brake control, regardless of mileage. This is a known, systemic engineering defect that is currently the subject of active federal class-action litigation (XXX v. General Motors LLC). This defect did not just cause an immediate life-threatening braking failure, it completely contaminated the oiling system, destroyed the entire engine, and rendered the vehicle a total loss requiring a full engine replacement. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552