2020 GMC Terrain complaints

Brakes stopped working while driving. Yes it has been reproduced by mechanic. No it has not been inspected by manufacturer. “Service Brake Assist” message populated after failure.

The contact owns a 2020 GMC Terrain. The contact stated while reversing, the rearview camera screen displayed a blue image. There was no warning light illuminated. The dealer was notified of the failure and informed the contact that a fee would be charged for a diagnostic test. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure and referred the contact to the NHTSA Hotline. The failure mileage was approximately 104,000.

The contact owns a 2020 GMC Terrain. The contact stated while driving 20 MPH, while attempting to slow down, the brake pedal was depressed; however, the brake pedal felt abnormally stiff. In addition, the vehicle hesitated to come to a complete stop. The contact became aware that the driver's side and passenger’s side struts had failed. The check engine warning light was illuminated. The vehicle was taken to the dealer where it was diagnosed that the brake vacuum pump needed to be replaced. The brake vacuum pump was replaced, and the vehicle was repaired. The manufacturer was notified of the failure and referred the contact to the dealer for assistance. The approximate failure mileage was 17,361.

My vacuum pump went out. my brakes went out at 86k miles. very pour design.

In September 2024 i was driving down the freeway and my car shuttered like the transmission was slipping. I then proceeded to get over into the right hand lane incase i needed to pull over thankfully, because then i lost use of my breaks, and then my ability to accelerate and steer. Then my car just shut off and would not stop. My vacuum pump just broke with no warning, it has been replaced and my car still won't start, it's going on 5 months now and they still can't figure out why.

The engine in my 2020 GMC Terrain is consuming oil at an alarming rate, burning through a full supply within one hour of operation. This excessive oil consumption has repeatedly caused significant damage to the coils and spark plugs, rendering them ineffective within 24 hours. The issue has led to multiple cylinder misfires, poor vehicle performance, and a transmission stall, posing a serious safety risk while driving. The GMC mechanic at Jim Ellis Buick GMC diagnosed the problem as internal damage to the pistons, which they state requires a full engine replacement. They also confirmed an internal oil leak within the engine, which is contributing to bad emissions and further degrading vehicle performance. This defect not only compromises the reliability and safety of the vehicle but also raises significant environmental concerns due to the excessive oil burning and emissions. I am requesting a thorough investigation to address this issue and determine whether it is part of a broader manufacturing defect affecting similar vehicles.

No warning, the brake pedal went stiff as a board. No brakes could not stop doing 35 on a residential road. Had to coast to a stop in neutral.

The brake system failed. No warning. When the brakes failed, driver ran the car into a tree to stop instead of hitting pedestrians or other vehicles

Every time it rains, the floorboard of my car is soaking wet. I took it to the dealership, and they stated the leak is coming from inside the firewall. I have only had this vehicle for 2 years and just recently moved to a house without a garage. Now that I am just now noticing it, I am wondering if it was like this when I bought it, but I am only noticing it now that I do not have a garage. They want to charge me over $1,000 just to take apart the dashboard to find the leak and that is just insane. There is no telling how much mold, rust, etc. could be in my car from this leak.

My car sunroof drainage system is not draining properly and GMC won’t see me for a month. There’s an excessive amount of water that’s pooling in the rear passenger floorboards buckets of water.

The contact owns a 2020 GMC Terrain. The contact stated that rain water had leaked from the sunroof drainage into the vehicle causing the floor carpets to become saturated with water and mold had developed inside the vehicle. The contact also discovered a pool of water inside the spare tire well. The vehicle was taken to the local dealer who replaced the sunroof motor and sunroof liner, unclogged the sunroof drainage assembly and replaced the carpets. The contact indicated that later the failure had reoccurred although the sunroof drainage assembly was consistently unclogged each time the vehicle was in for service. The contact had also experienced respiratory illness due to the mold present inside the vehicle. The manufacturer was notified of the failure but no assistance was offered. The failure mileage was 12,300.

Vehicle has not recently been inspected, backup camera has recently gone out leaving only a blue screen with "service rear vision system" to my knowledge nothing has happened to the unit that would cause this. Regular day to day driving, there was nothing that would have given me any notice that this would be happening.

The contact owns a 2020 GMC Terrain. The contact stated that while his wife was driving 5 MPH and exiting a parking lot, the vehicle inadvertently stalled. There was no warning light illuminated. The vehicle failed to restart. The messages "Low Battery" and "Start the Vehicle" were displayed. The contact stated that the brakes had seized. The vehicle was towed to the dealer, where it was diagnosed and determined that the fuel pump and the fuel pump driver control module needed to be replaced. The vehicle was being repaired. The manufacturer was notified of the failure and informed the contact that the vehicle was not covered under warranty. The failure mileage was 45,175.

My Terrain has a light that has been coming on for a couple months. Service Brake Assist. I took it to the dealer after my brakes locked up and about $800 after getting it fixed the light continues to come on. The forward collision light comes on every time I start the car. More the check engine light came on and says engine electrical system. What the heck is going on? I love this car and take very good care of it but I feel like the $800 that I just spent was a waste. I fear that I will get in a wreck like when the brakes totally locked up and I couldn't press on them.

The contact owns a 2020 GMC Terrain. The contact stated while in reverse(R), the back over prevention camera displayed a blue image on the screen. The dealer was notified of the failure but offered no assistance. The manufacturer was also notified of the failure and referred the contact to the NHTSA Hotline to report the failure. The vehicle was not repaired. The failure mileage was approximately 58,000.

Slowed down from coming off of the highway to turn into the gas station and couldn't slow down. The brakes FAILED. Was trying to pump them and was able to come to a forecful stop, nearly colliding with the car in front of me and then again at the gas pump. Car had a failed vacuum pump at 65,000 miles. If this happened during normal rush our, my kids and I would have been sandwiched between two cars. Fatal flaw that clearly GMC already knows about. The Terrain should be included in the recall.

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.

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.

While driving reduce engine power light came on and the brakes gave out. I weigh 250 lbs and took all my strength to get brakes to stop car. I tow it and mechanic showed me vacuum brake pump blew up and went into engine. He replaced that and timing chain but still needed work. Towed it to dealer and it needs a new engine $11 000. The dealer informed me they see this alot. ! Why has GM recalled some on the vehicles that has this pump but not the terrain. This is dangerous. If my daughter was driving she couldn't stop this car. It's now junk.

While driving I had to push the brake to the floor and a light came on saying reduced engine power. I pulled over right away and had my car towed to mechanic. The vacuum brake pump exposed and parts went into the engine. The mechanic got all the parts out but now engine has low compression and needs a new timing chain. This is over $3,000 so far. Gm recalled other vehicles with the exact same pump ? Why not the terrain.

The vehicle is a 2020 and should not already be having electrical issues. The vehicle repair is over 5k for needing a starter motor, water pump and drive belt. A starter should last up to 100k miles and water pump should last 10 years not 4. This vehicle is a lemon and should not have so many issues.

Incident happened August 9, 2020. Brakes suddenly stiffened and unable to stop vehicle. There were no warning signs or indicators. Thank goodness I was going at a lower speed and was able to coast into an area to stop. Ended up being the vacuum pump. This needs to be recalled ASAP. This could have been a fatal accident. I have kept the old vacuum pump as well as the pieces that were thrown from it that the mechanic had to dig out.

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.

As I was driving, brakes became very hard to press. I was barely able to slow down to bring the car to a complete stop. Brakes became very stiff and required a ton of force to come to a complete stop. This came with no warning signs or alerts from vehicle. It was only after this occurred that the Service Break Assist light came on.

On Wednesday, June 26, 2024 my 2020 gmc terrain unexpectedly malfunctioned and failed to restart. The engine light came on and I attempted to restart it for nearly 2 hours with no success. Fortunately, it finally started and once I got it home my fiancé plugged the car up to the code reader. P129F “Manufacturer Control” were the results. After further researching, this is for the fuel pump/fuel pump control modular assembly. In January 2023, NHTSA released a notice for my exact vehicle for this very scenario I experienced. And as of June 6th, 2024 a class action lawsuit was filed against gmc for this issue as well. My vehicle is not able to be repaired due to 1) my vin not being included on the recall list and 2) all the parts that were in inventory are also deemed unsafe due to the lawsuit documents shared online and this has caused a nationwide back order per my conversation with 3 gmc/chevy dealerships. At this point my vehicle is unreliable and unsafe to transport myself or my children.

Purchased Vehicle brand new- Beck & Masten Buick GM - Houston, TX [XXX] Performed rout maint regularly. Last oil change 1-5-2024 before catastrophic failure and complete engine seizure. Towed to Wiesner GMC [XXX] 1-12-2024: Mileage on car roughly 99K- had no issues no check engine light, no mechanical failure or indication that anything was running other than normal. No Start on [XXX] PM after work, tried to return next day with battery , changed out battery, engine still would not start, after new battery installed and we attempted to start, that is when engine started making loud shaking motion while attempting to start, windshield wipers came on randomly. First initial diagnostic: Found all oils & fluids in check, could not identify cause of failure, would have to break down and take apart. Had to authorize the tear down at a 1800.00 cost, 2/2/2024: Broke down engine, found that the crankshaft would move one way , but not other, removed the engine from transmission and now crankshaft moves freely. Now the AC comp is locked up (excessive play on magnet & clutch) , tech still unable to identify what caused the failure, they advised that they found traces of metal in oil pan, scored cylinder walls, starter shorted as well. They still could not indicate where these metal pieces came from, how or that it was due to owner negligence or manuf defects. Again this is a vehicle with 99K Miles and now we were looking at a 15K price tag for a new engine, turbo, AC, starter on a car th

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.

This Saturday morning driving my family to Bradenton as I was coming off the hwy to my exit when I experienced a brake fail I thought, brakes got real hard and I couldn't stop the car on time like I wanted to, so I had to press the brakes pedal harder to come to a complete stop, three different places no one knew what could be the problem until I took it to GMC dealership they can only give a code P0556 / U0401 SERVICE BRAKE ASSIST, seems it was too late to checked out they where about to close , something to do with the busters not sure yet but it's getting checked out tomorrow morning, I was driving on cruise control at a speed limit when this happened, will let you know what's the result of my situation.

While driving my vehicle, check engine light came on. Then, my car proceeded to flash about 4 warnings on the dash, Fuel Level Low (had half tank of gas), Engine Power Reduced, Service ESC, and Service Transmission. My vehicle shut itself off while driving 55 down a main highway and put itself into park. Forcing me to pull over and be stranded on the side of the road. In the way of other cars, with no way to get out of the way. I then had to shut car off, wait, and start it back it up. However, after the first time this happened, I cannot drive my vehicle more than 15 to 20 minutes without it doing this to me over and over again. To make matters worse, I am 37 weeks pregnant, and the last thing I need is to be without a car. I also had just gotten my vehicle inspected and an oil change the week before, with no issues to show. The only thing I did to my car before it did this, was remote start my vehicle, which I do every single morning and have for the little over a year I've owned this car. Also, my car has less than 60,000 miles on it!! The mechanic who is currently working on fixing this issue for me, has concluded it to be a throttle body, or the actuator of the car.

Brake booster failed with no warning. Brake pad was hard to push down as I exited the freeway. I came close to hitting the vehicle in front of me which would have resulted in a bad car accident. There were no warning. This is extremely dangerous and is a risk to not only the driver but also to vehicles in the path of a vehicle that cannot stop. This needs to be a recall along with the other vehicles that have a recall for this part.

Heard a ticking noise coming from the engine compartment. I opened the hood to investigate which I first check oil level as sounded like a lifter making the noise but all fluid levels was normal. I drove home and 3 miles later ticking noise went away and my adaptive brake assist came in and the brake pedal was hard to press. Luckily I lived another mile down the road so I got the car home and safely parked it. One of the symptoms is hearing a ticking noise from engine when a braking component fails. Further learned could be a vacuum issue which needs a software update which makes no sense. Had I been traveling highway speeds when this happened this story could have a had a very different tragic ending. Car has less then 53000 miles on it

The contact owns a 2020 GMC Terrain. The contact stated that while at a stop, there was an abnormal burning odor coming from the vehicle, with the service brake assist message displayed. The brake pedal became firm, and the contact used excessive force to stop the vehicle. The contact pulled into a gas station and restarted the vehicle while the check engine light was illuminated. Despite the failure, the contact was able to drive the vehicle to the residence. The contact inspected underneath the hood and discovered an oil leak as well as black soot that had covered the entire engine. The dealer was notified of the failure and provided the contact with a diagnostic fee for an inspection. Upon investigation, the contact discovered NHTSA Campaign Number: 20V668000 (Power Train) which was linked to the failure. The manufacturer was not notified of the failure. The vehicle was not repaired. The failure mileage was approximately 57,000.

On 4/10/2023, I took my vehicle to a local GMC dealership because it was stalling and didn't have any power. Upon accelerating the vehicle it would stall and take off at a high speed. The dealership has had my vehicle periodically from April 2023 and it presently sets at the dealership because they ain't getting a code, But after the dealership drove the truck for over 200 miles, they were finally able to duplicate the stalling yet are not able to diagnose the problem!! This vehicle is very dangerous to be on the road and I have almost gotten hit twice and I'm not driving the vehicle anymore at this time. I have previously reached out to you all and I would be most thankful if you could get in touch with me. Thank you

Driving down the road at 40mph when the car shifts to park, the brake and steering wheel lock up and the car won’t accelerate. I had to pull over because I almost crashed due to the abrupt shift. Once pulled over I tried to restart the car but once off and back on it wouldn’t allow me to shift or drive it. The steering wheel and brake remained locked. It has happened several times over the past week.

Driving down the freeway and all of a sudden got a service break assist notification and without warning I was unable to stop the vehicle. I was able to coast my way off the freeway and upon my exit I tried to pull into an empty parking lot but there was a fire fence I ended up crashing into which is probably what brought the vehicle to a complete stop. This is very dangerous and I have read numerous complaints from other 2020 terrain owners who have experienced the same problem. Mechanic stated I need need vacuum pump for brake booster which of course my warranty doesn’t cover. Something seriously needs to be done about this. My accident could have been a lot worse

I was driving on the interstate when my brakes went out. I was able to get off at and exit and pull into a gas station but had to put on the emergency brake.

GMC 2029 Terrain Our car broke down three times after a new engine was put in. After one week it had to be towed again to put in a third new engine. It has been fixed since Aug. 1st but GMC has yet to reunite us with the car 2000 miles away. We’ve made car and insurance payments for almost three months with no vehicle in our possession. It was under warranty. No loaner or rental car has been issued to us. Nobody calls us back. Terrible customer service by GMC.

2020 GMC Terrain Engine stopped working. Put in new engine. After one week new engine blown. We were 2000 miles away on vacation. I need a free rental I was with no car for a month and after only one week again for 3 weeks. Compensation request: Lost wages Hospital visit Extra hotel nights Gas Food car and insurance payment

After heavy rain the backseat of the car was flooded as well as the rear wheel well likely due to the sunroof not draining properly. This led to electrical failure of the sunroof mechanism and potential to damage other electrical elements. This will be looked at by the dealership but have read that this is a known issue.

While on highway service brake system warning light came on,brake became hard to apply almost causing an accident. Vehicle had to be towed to a repair shop(dealer).after paying over $1600 the problem was not resolved and found there are numerous complaints about issues with the terrain and no recall issued.are they waiting til someone dies before a recall?

My vehicle begin stalling when accelerating (mostly after stopping) June 2023. My vehicle has almost cause me to have two accidents because it intermittently stalls when I try to cross an intersection. This is my fourth time taking my vehicle to the GMC dealership, and they tell me they can't find anything wrong if there is not a code. I have reached out to Corp, and I'm waiting to see if they can help get to the bottom of my problem. My car has been sitting at the dealership since June 30th 2023....I call the dealership periodically, and they never reach out to let me know what's going on. I am afraid to drive my vehicle at this time because next time another car may not be able stop and give me time to get across the road. I'm filing this complaint because I seriously think someone is gonna get killed.. Thank you

2020 GMC Terrain SLE Elevation Package 83,000 miles and needs complete engine rebuild @ cost of $10,700 per Dealership Service. Was told “I drove the vehicle with low oil” which Inturn is the cause of needing engine rebuilt. I have had this vehicle serviced, oil changed regularly etc NOT ONE TIME has the oil pressure/low engine oil nor anything related to oil illuminated on my dash. CEL yes after it apparently was too late and damage was done which showed code P06DD And P0324 through OnStar Diagnostics. There are also other complaints with same issue, and no notification of oil /oil pressure issues with relatively low mileage that have led to engine rebuild. I still owe on this vehicle through GM Financial, and a $10,200 engine rebuild on top of that… Not what I would expect out of GMC~

I was driving approximately 75mph on the interstate. 3 hrs into my trip I started feeling hot so I turned the a/c up. In my peripheral vision I saw orange and thought a car was beside me on fire. Immediately I realized it was my vehicle. I immediately slowed and came to a stop. I put it in park and opened the door. By the time I started to exit there were flames higher than the rear windows. A car that was behind me stopped. They said about a mile back there was a spark under the car by the rear tire. Then it went up in flames.

My 2020 terrain is now at 33k+ miles, I have had repeated instances with my car not accelerating properly. I would be at a full stop try to start to accelerate and not move push down a little further on accelerator and start crawling forward. I would move approximately quarter mile before the vehicle would jerk and accelerate very quickly to a speed well over where it should go to. I.e. I know because I’m starting in traffic I’m not trying to take off at thirty but when the jerk happens I can be jolted to 40-45 mph. The other issue is people behind you don’t realize what’s going on and I have been hit almost twice thankfully they were able to avoid me by going around. No warning lights have come on. This last insistence not only could I not accelerate, but cruise did not want to turn on, the emergency brake didn’t want to work, and the air conditioner was loosing power. I plan on having an independent service center inspect the vehicle, my husband was able to repeat the issue so I’m sure they will also. The first incident was in May and I have had 5 but thankfully I don’t drive that much.

Screen system prompts to accept terms of service while moving. This is unsafe and the system should know it is in motion. Unsafe programming, require manufacture to only prompt when system is at reset. Require OTA reprogramming.

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 somethin

The contact owns a 2020 GMC Terrain. The contact stated that while attempting to restart the vehicle, the vehicle failed to start. The vehicle was towed to the local dealer who diagnosed that the fuel pump was faulty and needed to be replaced. The vehicle was not yet repaired. The manufacturer was not yet notified of the failure. The failure mileage was 42,000.

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.

I was driving down The expressway. The traffic in front of me came to a stop. When I went to apply the brakes I had no breaks. The pedal was as hard as A rock So when I realized I couldn't stop I swerved over into the breakdown lane. And continue to pass cars at a high rate of speed until I got the car to stop. There were no check engine lights on Then I had the car towed to the Dealership Where they tell me is a break vacuum pump. That has damaged The Cam shaft. Pistons and rods in the engine. Totaling $7200. In damage. No one seems to care and I still owe 20000 on the car. Car has 71000 miles on it.

The car has been in the shop for the turbo being over boosted four times and is getting hot, so they put thermo tape on the part, and now what if the car catches on fire? This is an electrical issue that needs to be solved.