2020 Gmc Terrain Complaints

  • Service Brakes, engine 06/03/2026

    During my daily commute to work on the interstate the service break assist message came on my dash and when attempting to break the pedal was very hard, to the point where I had to push extremely hard and quickly realized I had to brake much much soon than normal to prevent hitting other vehicles. Sudden loss of brakes put me and other drivers at risk due to my near inability to slow down or stop and the sudden and unexpected nature of the event.

  • Service Brakes, engine 06/02/2026

    I am a [XXX] resident. While commuting to work in [XXX], my GMC Terrain experienced a sudden, catastrophic failure of the brake vacuum pump while traveling at highway speeds. When I attempted to slow down for the exit, the brake pedal instantly became extremely stiff and nearly impossible to depress. I realized I had suffered an absolute loss of power braking assist. To avoid a high-speed collision with heavy highway traffic, I was forced to deliberately steer onto the roadside rumble strips, relying on tire friction to slow the vehicle down. This severe near-miss left me terrified and distraught. Because the shoulder was narrow, my disabled vehicle was left partially protruding into the active roadway. Passing cars sped by so close that my vehicle was violently rocking, creating an incredibly unsafe situation. I was forced to call the State Police for emergency assistance. They dispatched a trooper and a tow truck to remove me and the vehicle safely from the highway. The vehicle was...

  • Electrical System, engine 05/22/2026

    Transmission wouldnt shift. Sensor in car is causing issue, code is N 202321840

  • Service Brakes, engine 05/18/2026

    I am submitting this complaint regarding a serious and dangerous brake failure involving my 2020 GMC Terrain SLT with approximately 150,000 miles. While driving, the vehicle suddenly experienced a vacuum pump failure that caused a severe loss of braking ability with no warning beforehand. The brake pedal became extremely hard, and the vehicle would barely stop. This created a very dangerous situation and could have easily resulted in a serious accident. Thankfully, I was not driving at a high speed when the failure occurred, and there were no vehicles directly in front of me at the time. However, only minutes earlier I had been traveling approximately 65–70 mph on the highway. If this brake failure had occurred while driving at highway speeds or in heavy traffic, I truly believe it could have caused a major crash resulting in serious injury or death. What concerns me most is that there was no warning before the brakes failed. No warning lights and no issues with my brakes. The sudde...

  • Service Brakes 05/01/2026

    The vacuum pump for the brake system failed catastrophically while driving causing damage to the brake booster and lodging metal debree into the engine components. This happened at less than 100k miles on a 2020 gmc terrain.

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