While driving the vehicle which only has 68,000 miles the reduced engine power warning light appeared. As quickly as was safe the car was pulled to the shoulder. It was towed to the dealer who states the Vacuum pump seized causing the camshaft phase actuator locating pin to spin. Originally they stated a new camshaft and vacuum pump were needed at $3,500, but now state the entire engine is damaged and must be replaced at cost of $12,000. The vehicle was well serviced and this manufacturing flaw lead to the vehicle be stopped on the road putting both the occupants and others around at risk.

- Ontario, CA, USA

Rear side windows in hatch area leaked filled up spare tire compartment with about 3-4 gallons of water. Now navigation doesn't want to work, sunroof not working, electric systems are not working right

- Willits, CA, USA

The 2018 GMC Terrain has the AutoStop feature but does not incorporate a switch to defeat AutoStop. In heavy stop and go traffic or when fast acceleration from stop is required, the response of the engine in having to restart creates not only a nuisance condition but a severe accident hazard. It not only hesitates from stopped, it lurches forward after hesitating, which could cause a collision with a vehicle in front. I have had several other vehicles equipped with AutoStop, and all of them have a defeat or cancel AutoStop switch to allow the operator the opportunity to turn AutoStop Off. My 2018 Terrain Denali is now on its third battery. Having a dead battery in traffic also constitutes a safety hazard as does the inherent danger of using jumper cables. I have asked my dealer for a way to defeat the faulty feature, but they either cannot or will not do it. There must be a software code to easily allow this that the dealer can perform or a slight hardware modification to allow the operator to defeat AutoStop when it creates a safety hazard.

- Magnolia, TX, USA

Driving 2,5 hrs from Binghamton, NY towards Long Island on Saturday. We took a short break and after that I got onto the highway and not even hit the 50 miles/hour speed I received -??engine power reduce-?? alert on the dashboard and car stalled. I was able to pull the car off the road. I was provided a tow truck by the state police and moved to closest GMC service, GRAND PR?ZE GMC Nanuet, NY. This car has only 30,309 miles and it-??s 2018. The car has been fixed by replacing 5 parts, oxygen sensor, pcv tube, air inlet tube etc. We ended up paying $1,460 just before the Holidays. Rightfully, we are very upset with this unexpected event driving a basically brand new car, in 30000 miles. This car has been mostly driven by my wife who is in 60s in local streets not exposed to harsh enviroments. There is a recall I noticed online for 2019 models and almost from the same area of throttle body, but nothing for 2018. Now, my wife and I hesitating to drive the car. Are we going to get stuck on the road again?

- Lindenhurst, NY, USA

There is an has been an issue with my electrical system says I purchased this car in 2017. Myself believe that the issues have not been documented until 2020. When my racy begins to run out, my engine light has been coming on and I-??ve been getting the same code P1101 I took my vehicle to GMC and they told me that the engine light came on because the tape came loose. I brought this vehicle and there-??s no way there should be no tape on it. The service tech also told me that if the problem continue to bring it back and I will have to pay $120 or whatever the label rate was for them to research I contacted GMC to file a complaint and I received the whole bunch of calls from a guy named Kevin. I believe he told me that he had been contacting mike haggerty and no one returned his call and that he was sorry he couldn-??t help me. This is my report number one of them from GMC. sr:9-6167743153. Everywhere I take my car they tell me that they have a lot of customers with the same issue and they tried to replace what the code is matching which is the mass airflow sensor but that does not help there is some type of problem with the engine or the electrical system with this vehicle. I am not the only consumer that has had this problem. I don-??t know what to do. I have two kids I cannot afford to keep pay and label rate for them not to find the problem. I am also attaching the typical email that GMC sent out when they are working with the dealerships because I have been in contact with them and the person that was calling and then they sent me this email.

- Chicago, IL, USA

Last year this time brakes went out at 50 mph power brake module imploded from inside out. The part was on national back order. Second incident car stopped immediately while traveling 40 mph no warnings or anything both incidents could of been horrible. Not sure on second incident the issue yet car is in shop. Both incidents are safety concerns for myself and others. Driving at average speeds and something malfunctioning is a great concern of mine. I contacted GMC no one to talk too just chat and the person on the other side told me it was no concern of theirs all was dumbfounded by the conversation but until I said I was putting on social media and bringing to everyone attention her entire tune changed in regards to part and service. So I researched locally and luckily I found the part they had one left and I was told by dealer that it is an issue on these vehicles. Both safety incidents have been within a year of each other 2022 and 2023

- Georgetown, OH, USA

The vacuum pump started leaking and the car was parked immediately. When The pump was pulled out to be replaced, the reason for the leak was identified. The vacuum pump had busted into small pieces which are now in the engine.

- Point Pleasant , WV, USA

Catalytic converter went out at 101,650 miles and the dealer has no replacement part. This is the diesel engine, almost every other year was recalled and they extended the warranty to 100,000 miles. And they stopped making this engine. Seems like they should at the least have a replacement part for a car 5 1/2 years old. They also said the 2017 were recalled, this vehicle was built Jan 2018. The vehicle currently will only go 5 MPH so it cant be driven. There was no warning of the failure.

- Oak Hills, CA, USA

In mid traffic my 2018 GMC terrain just stopped with no warning, no check engine lights, no smoke from the vehicle, nothing. I was in Charlotte traffic, driving, with my family in the vehicle, the car stopped right in the middle of driving, and I had to quickly and sharply turn the wheel to got into a median to avoid hitting the car in front of me and avoid being rear-ended. The dealership informed me that the vacuum pump in the engine cracked (broke) causing another part in the engine to malfunction. There were no, none, warning lamps, messages, or other symptoms prior to this incident that would of indicated a problem so that I can proactively service the vehicle and keep my family safe.

- Belmont, NC, USA

I was driving my vehicle, there was no indication that the vehicle was in need of servicing or that something was wrong with the vehicle, no check engine lights were on. The vehicle stopped in mid traffic, just completely shut down in active traffic. I had to serve my vehicle in to the curb/median to stop if from hitting traffic ahead of me.

- Belmont, NC, USA

I was coming to a stop with my vehicle and the brakes would not work. I carefully got my car home and to a shop. It was determined that the break booster pump broke which caused metal parts to go into the engine. Now my engine is blown! Bought my car brand new in 2018 and kept up with regular vehicle maintenance has 90k miles.

- Lima, NY, USA

The dealer has not been very familiar with the diesel option in this vehicle. Dealer has found nothing wrong with the engine in this regard. Now the car is out of warranty and will be very expensive to fix according to outside mechanics. The car is experiencing severe BLOW-BY When the oil filler cap is removed while the engine is running, the pressure coming out of the engine is very high. I understand this is a very bad thing to be happening. The car has an engine light on, and it will not go out.

- Corpus Christi, TX, USA

Camshaft failed during driving causing vehicle to become disabled in the roadway and almost hit many times. The camshaft is being repaired by ase certified mechanic at an independent service center. A reduced power notice cam on a few minutes prior to the failure.

- Winter Park, FL, USA

When driving the car at low speeds, or right after having been stopped for a few moments. Upon, acceleration, the car will sometimes go into a limp mode. On the DIC, will be displayed a warning about how the car will have the speed reduced after 175 miles and to check the emissions system. The speed has already been reduced at that point. Also displayed maybe a warning about how the power has been reduced. USUALLY, if I turn off the car and wait about a minute, I can restart the car and drive at a normal highway speed again. But not always. The warning on the DIC, will usually turn off if the car does return to normal speeds after about 5 - 10 miles. However, the check engine light may still stay on for several days. This problem can be a daily occurrence. I've had the car in the shop several times, and they have been unable to fix the problem. The car can be unpredictably unsafe, when speed is instantly reduced to 30 mph!

- Corpus Christi, TX, USA

I have a 2018 GMC TERRAIN which I bought brand new from General Motors. In May 2022, the vehicle started jerking/hoping and trying to stall when the speed gets to 55 miles per hour or higher. I have taken it to the dealership on three different occasions for repair and I still have this issue. General Motors engineers were involved in every step of the repairs. They just do not know what is going on with the car or fix it and they are too stubborn. The dealership told me today that they cannot do anything else to the car. They also said they had a code from the engine last week and General Motors said they do not know what that code means. They are forcing me to accept/drive the car in this unsafe condition. I have contacted them multiple times and they do not care.

- Toledo, OH, USA

Beaverton GMC did repair work on my vehicle. During the inspection they said they found the radiator leaking from a number of spots and it needed replaced. It has never leaked and did not need replaced. Why did they do it? I as for the parts but they tossed them and would not give them to me.

- Newberg, OR, USA

Catalytic converter failed when driving damaging the engine. Vehicle undrivable and waited for repair at shop for over 90 days. Engine warning light keeps coming on with error code P1186 that the GMC dealer can not fix.

- Newberg, OR, USA

My auto started leaking some kind of oil.not sure what kind but I can see accumulation on driveway concrete pad. Had motor oil & filter changed in case it was a O-ring or not tight enough. It continues to leak.

- Goliad, TX, USA

My 2018 GMC Terrain has major issues that almost caused me to hit a wall on the expressway due to a brake assist issue that other owners have a issue with and GMC has done nothing to help the buyers, where can we the buyers get help with issues GMC is well aware of??

- Park Forest, IL, USA

Recall on the engine block heater. The dealership is unable to get the part to replace. I took in over 6 months ago and still have nothing.

- Farmington, CT, USA