2020 GMC Terrain

1- at 71,000 miles in 2022 brake vacuum pump “exploded” broke into many small pieces in the middle of driving. Causing brakes to lock. Brake pedal was brick hard. Hard to maneuver the car out of traffic without causing a collision. Luckily car was not being driven at high speed. At time of repair costing $1,000 Mechanic informed me that the pump was made out of a non metal material and he could not fish the small particles out of the motor with a magnet. The motor would need to be taken apart, cleaned out and reassembled….. From this point forward the car drives in “low engine power mode” even with repairs completed and codes cleared. 2- 2 years later the same part “brake vacuum pump” exploded again. Another $1000 repair. At this time we discovered that the fine particles that were not removed from motor has now knocked the timing off by 8%. Also it has caused a knick in a seal causing an oil leak under 100k miles $1800 repair. After these extensive repairs…… The car emits gas fumes into cabin. The smell is so strong it can’t be parked in the garage because it circulates through the house. Even when car is not running. The Car can’t be driven because risk of fire or explosion from gas. Fuel system gets cleaned. Injectors replaced. The car temporarily runs without the gas smell. 2 weeks later the gas smell returns Come to find out the fuel pump failed. Search online and find there is a recall for fuel pumps in this same make model and year. But not this vin number. The car has been a headache from day 1. Recall the whole car at this point, to have so many faulty parts in such major systems of a car is crazy.

I was driving 55 miles an hour on an Expressway. And suddenly my truck just shut off.The brake became very hard unable to break very scary situation for me and my children. Engine power was reduced and would not start, many errors came up. The vacuum pump failed, which also caused the cam shafts to fail.The vacuum pump exploded into pieces and sent metal into my engine.

While driving I received a "service brake assist system" alert and a check engine light. After this happened the brakes were extremely hard to press. I had to put my entire weight on the breaks to stop the car. The brake "assist" feature really is making the brakes functional. We were able to safely get to the side of the road. We found a vacuum pump failed and needed to be replaced. There was no sign that this was failing; it worked, then it didn't.

While driving down the interstate a notice popped up on my dash about the brake assist. When I attempted to slow down the vehicle to safely pull over the brake pedal was very hard to push. I was able to slow the vehicle to a complete stop but needing to use both feed and press hard with all my weight. Once the vehicle was parked and shut off I turned it back on to have the check engine light pop up on the dash. I contacted Onstar and was towed to a dealership. The brake vacuum pump had broken off at the cam shaft and required extensive repairs. It is my understanding that this is a common occurance and there were previous recalls on the other style Terrains due to the same issue. yet they used the same part on the newer body style being fully aware of the design flaw.

Since August 2024, my brake booster has gone a total of five times each time with the notification on the dash service brake assist. And it just went again as of two days ago. I’ve brought it to Firestone where they have replaced it each time with a warranty on the part. I called them yesterday to tell them that it went again and they refused to fix it telling me that they got the part from the dealership and that I would have to take it there so the dealership would have to figure out what’s wrong with it as to why the car is “chewing up” the part. I have young kids and this part has gone five times.

While driving my brakes failed. I was unable to stop my car, my brake pedal became very stiff and I could not stop my car. There were no warning signs or lights on indicating there were any issues with my car prior to this happening. I had to have my car towed to the dealer. The current estimate is for a vacuum pump failure resulting in camshaft damage. Both need to be replaced. I see other GMC cars were recalled for what appears to be a similar issue. I am lucky no one was injured as this could have very easily resulted in a fatal event. I have never heard of such a thing happening before and am beyond belief that this has occurred. This is the third repair I've had done this year. I have also replaced a booter pipe and valve gasket due to leaking oil. The amount of repairs required in such a short a time seems excessive.

While driving on a main road at around 45mph the vacuum pump that supplies brake fluid to the brakes failed. The car was unable to be stopped and had it not been late in the night I could have crashed into other vehicles on the road or hit someone walking. There was not indication prior to the malfunction and was very sudden. This issue has been observed by the dealer as well as multiple other individuals with the same problem for this make and model of car as well as others by the same manufacturer for similar years of manufacturing. This part has also been shown to break into the engine causing complete engine failure due to lack of a shear pin on the vacuum pump.

I filed a complaint with NHTSA on November 3, 2025, about my brake system. Here is another one adding more information. I had to have another brake system part replaced. This time it was the brake booster. Cost $1441.63 (covered by extended warranty actual cost to me $100.00.) So far, I have had the booster sensor replaced twice, the vacuum pump and now the brake booster. I asked the mechanic how many parts related to this system were left to replace? This vehicle has 66,000 miles on parts for the braking system started needed to be replaced at 37,000 miles. The total cost for parts, labor is about $500. That does not include the loss of use for this vehicle which is about 15 days. Taking days off of work about 6 days. This has been a problem for GMC Terrains since 2015; there is still a problem with 2020 model year. Please do something before there is a loss of life due to brake failure.