10.0

really awful
Crashes / Fires:
3 / 0
Injuries / Deaths:
2 / 0
Average Mileage:
4,418 miles

About These NHTSA Complaints:

This data is from the NHTSA — the US gov't agency tasked with vehicle safety. Complaints are spread across multiple & redundant categories, & are not organized by problem.

So how do you find out what problems are occurring? For this NHTSA complaint data, the only way is to read through the comments below. Any duplicates or errors? It's not us.

2020 GMC Terrain brakes problems

brakes problem

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2020 GMC Terrain Owner Comments (Page 1 of 2)

problem #27

Jan 142025

Terrain

  • miles

A D V E R T I S E M E N T S

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

- Seymour , IN, USA

problem #26

Sep 152024

Terrain

  • miles
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.

- Roseville , MI, USA

problem #25

Dec 282024

Terrain

  • miles
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.

- Xenia, OH, USA

problem #24

Dec 262024

Terrain

  • miles

A D V E R T I S E M E N T S

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

- Palm Bay, FL, USA

problem #23

Nov 302024

Terrain

  • miles
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.

- Cuero, TX, USA

problem #22

Oct 162024

Terrain

  • miles
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.

- Carrollton, TX, USA

problem #21

Aug 132024

Terrain

  • miles

A D V E R T I S E M E N T S

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.

- Euclid, OH, USA

problem #20

Aug 142024

Terrain

  • miles
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.

- Euclid, OH, USA

problem #19

Aug 092024

Terrain

  • miles
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.

- Jacksonville , FL, USA

problem #18

Jul 042024

Terrain

  • 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.

- Baltimore , MD, USA

problem #17

Jun 212022

Terrain

  • 50,000 miles

A D V E R T I S E M E N T S

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.

- Royal Oak, MI, USA

problem #16

Feb 022024

Terrain

  • miles
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.

- Sanford, FL, USA

problem #15

Jan 312024

Terrain

  • miles
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.

- Little Rock, AR, USA

problem #14

Jan 202024

Terrain

  • miles
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

- Carrollton, OH, USA

problem #13

Sep 092023

Terrain

  • miles
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

- Warren , MI, USA

problem #12

Sep 102023

Terrain

  • miles
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.

- Fort Calhoun, NE, USA

problem #11

Aug 062023

Terrain

  • miles
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?

- Greensboro, NC, USA

problem #10

Apr 282023

Terrain

  • miles
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.

- Warren, MI, USA

problem #9

Feb 012023

Terrain

  • miles
The brake system is only working at about 5%. There are known defects with other GMC models of this year and this vehicle should be reviewed.

- Anna, TX, USA

problem #8

Jul 132022

Terrain

  • miles
Service brake assists light flashes on dashboard. Steering wheel locks up and jerk-??s loose suddenly when making a right turn, in these moments when the steering wheel jerks loose ;hands are off taken off the steering wheel otherwise injury can occur. Battery life 2 -yrs old is not performing optimally. Can not hold a sufficient charge and ESC light flashes. Vdnt valve leaks discovered.

- Bradenton, FL, USA

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