The contact owns a 2018 GMC Terrain. The contact stated that while driving at approximately 35 MPH going over a hill, the brake pedal was depressed but was firm and failed to depress as needed. The engine power reduced message was displayed and flashed on and then off. The brake assist warning light was illuminated. The service transmission message was displayed. The contact continued to depress the brake pedal until the vehicle responded as needed. The driver was able to pull into a parking lot, and the vehicle rolled to a stop. While driving, the engine misfired. Additionally, the vehicle failed to fully shutoff. The vehicle was towed to the local dealer, where it was diagnosed that the brakes had locked up and that the vacuum pump needed to be replaced. The contact was also informed that the cam shaft had fractured inside the engine. Additionally, the fuel injector, fuel line, and fuel pump needed to be replaced. The vehicle was not repaired. The contact related the failure to NHTSA Campaign Number: 19V645000 (Service Brakes, Hydraulic) and 23V013000 (Fuel System, Gasoline). The manufacturer was contacted, and the contact was informed that the VIN was under recall. The failure mileage was approximately 30,000.

- Chicago, IL, USA

On 9/3/23 I was travelling down interstate 94 in Illinois when all of a sudden my check engine light came on. Not knowing what the issue was, but knowing that the car still seemed to be OK and I was only a few miles from home I decided to drive home and figure out the issue from there. At this point I had no idea that the brakes had completely locked up. Once I realized what was happening I did my best to slow the vehicle down by decelerating, frantically pumping on the locked up brakes, and then finally slowing enough to take an exit and roll in to a gas station. Frankly, it was the most terrifying moment of my life travelling 70 MPH without the ability to stop. Upon inspection, the independent service tech informed us that the vacuum pump had exploded (yes, exploded) and that he had never seen anything like it, especially in a car with less than 70,000 miles. What component or system failed or malfunctioned, and is it available for inspection upon request" The vacuum pump failed and unfortunately it completely exploded so there were only a few pieces left inside of the engine. How was your safety or the safety of others put at risk? My brakes locked up completely on the interstate, with my family in the car, and I was unable to stop. Has the problem been reproduced or confirmed by a dealer or independent service center? Yes. The independent service center where I currently have the vehicle has confirmed, and spoken with GM. Has the vehicle or component been inspected by the manufacturer, police, insurance representatives or others? No, GMC refuses to do anything about it even though there is a prior recall for the same part on other GMC vehicles during the same time frame. I'm told it's the exact same part. Were there any warning lamps, messages or other symptoms of the problem prior to the failure, and when did they first appear" Yes, roughly 1 minute prior to the breaks locking up the "check engine" light came on.

- Gurnee, IL, USA

Driving on highway and all of a sudden I could not break - the car breaks failed to operate - had to slowdown by it self and pull to a McDonalds, I had the loss of effective braking with no warning whatsoever. We found out that the Break Booster Pump was destroyed without any warning from the electronics of the SUV.

- Mahwah, NJ, 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

The contact owns a 2018 GMC Terrain. The contact stated while driving 45 MPH, the check engine warning light illuminated. The contact stated while making a left turn the brake pedal was depressed but failed to stop the vehicle. The contact was able to continue driving without proper braking response to her residence. The contact stated she used the parking brake to fully stop the vehicle. The contact's husband took the vehicle to the local dealer, where it was diagnosed with needing an unknown pipe and vacuum pump to be replaced. The vehicle was not repaired. The manufacturer had not been informed of the failure. The failure mileage was approximately 79,000.

- Oswego, IL, USA

Driving home from our local town 4/15/2023, the brake pedal became to hard to push down. Check engine light came on as I got to my driveway, and that is 1 mile from the main road. My kids were scared to tears as was my girlfriend. Run a scan and dtc p0557. Come to find the vacuum pump on the top drivers side of motor is the part that is bad it broke inside the valve cover. Looking up the issue and find out it is a known problem and no recall. I have kept the parts and all receipts for the repairs, I have to do myself cause the repairs are way to much for me to pay out of pocket. This is a serious issue for this car and year and GMC needs to address the issue. Why has nothing been done yet"?? I am making payments on this car with no warranty for the car so I'm stuck fixing the car. But GMC knows that this is a problem and does nothing?!? I remember when American cars were good cars what happened to that time ?? And what happened to company's being responsible for the product they put out to customers" Guess that time is gone, I won't buy another American car again, unless it's a old Detroit built car.

- Barstow , CA, 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

Brakes go to floor an brake peddle starts to vibrate, (lost of brakes ) Brake assist light comes on. Vehicle has 27000 miles. Problem started at 6000 miles an was brought to GMC service centers 3 times for same issue. They replaced 3 different parts at a total cost of1600 dollars. Brake system is being replaced one part at a time at my expense, GMC has no clue what problem is. Will not admit there is an issue? Just got vehicle back for 3rd time an 3rd new part.

- Wildwood, NJ, USA

Vehicle stuck in emergency assist mood. Without warning I couldn't slow down/stop without putting alot of my weight on the brake breaks were so hard to press down.

- Follansbee, WV, USA

When trying to brake, brake pedal became extremely hard to push and Repair brake assist notification and check engine light came

- Knoxville, TN, USA

Vacuum pump went out brakes hard to push and I know gmc had a recall for this issue on other vehicles as well previously.

- Adel, GA, USA

Brake has to be pushed all the way down HARD to stop, brake assist warning comes up. I-??ve had the car for less than 2 years and it-??s way too new for anything to go out. Undriveable unless it-??s fixed.

- Harker Heights, TX, USA

While getting off the interstate, the brakes failed with no prior warning, or issues. The brake pedal became extremely difficult to depress and stopping distance was greatly increased. Could not come to a complete stop without using the emergency brake. We drove home (about 2 miles from the interstate exit) and about a half mile after the brake failure, a "service brake assist" light illuminated. Vehicle was towed to dealership the next morning. The problem was the vacuum pump exploded and caused vacuum to the brake booster to be lost, making the pedal difficult to push. Luckily this happened at 11pm and there was nobody in front of us, there definitely would have been a collision.

- Channahon, IL, USA

6/3/22 I went to the grocery store which is on a four lane road. When I left the store I had no brakes. On a four lane stop and go road. The was no warning just nothing peddle to the floor and now check engine light is on. I am reading this same problem repeatedly. I love this car but this is a serious hazard and needs to be addressed. We are all driving around practically rear ending people. I was an inch from the guy in front of me thank God the light changed as I was coming up on him or I would have hit him.

- Alliance, OH, USA

I was driving out of town (2 hrs from home) with my 2 small children and my mother, when I tried to slow to come to a stop my breaks did not work and I almost rear ended someone. It was sudden, there were no signs that my breaks were going to mess up. When I tried to look up recalls, there were none for my vehicle BUT there were MANY statements of people who drove gmc or gm vehicles that had the same issue with the vacuum boost for the brakes around 50k miles where the breaks just quit or were hard to use. It seems to be a common issue and is VERY unsafe. I cannot afford to fix the issue and I don't feel as though I should have to if other terrains have been recalled, except mine which I do not understand.

- Claremore, OK, USA

The contact owns a 2018 GMC Terrain. The contact stated that while her husband was driving 50 MPH, the brake pedal was depressed and went to the floorboard. The service brake assist warning light was illuminated. The vehicle was not taken to a dealer nor independent mechanic to be diagnosed or repaired. The manufacturer was notified of the failure. The failure mileage was approximately 69,000.

- Deer Park, TX, USA

The brakes are extremely hard to engage while driving. All 4 rotors are pitted with less than 30k miles. Doing some online research this is a common problem and should be addressed. I just did my first set of brakes at 100,000 miles on my truck.

- Windham, ME, USA

The vehicle experienced a sudden loss of braking and displayed a -??brake assist -?? fault message. The check engine light has illuminated. The sudden loss of braking was in a residential neighborhood traveling at 35 mph. I was turning during the loss of braking and was able to narrowly avoid collision with the cars at the intersection because I could not slow to a safe speed. The fault codes have not been read by the dealership yet nor has the repair been completed.

- Niceville, FL, USA

The "Service Brake Assist" issue in other 2018 GMC SUVs is happening in the 2018 GMC Terrain, but it is not part of the recall. Our brakes became EXTREMELY difficult to press right as we were turning onto the on ramp of an expressway. Thankfully we were smart enough to pull over and not get on the highway. Had we done so, I may not have been here to type this complaint. The brakes be come extremely difficult to press and that message shows. Dealership is going to charge me $400 to replace a vacuum pump - they were not interested in the information I have around this issue in other GMC SUVs since it isn't a formal recall on the Terrain. I could have died yesterday due to this braking issue. I've owned this car for 3 months.

- Redford, MI, USA