2018 GMC TERRAIN Complaints

View complaints related to 2018 GMC TERRAIN. The complaints found here are submitted by actual consumers with first hand experience. There are more than 220 complaints submitted for the 2018 GMC TERRAIN. You can submit your own complaint to the NHTSA or call the Hotline, Monday-Friday 8am to 8pm at (888) 327-4236, TTY: (800) 424-9153.

  • 2018 GMC TERRAIN
    - KATY, TX

    I purchased an Evenflo Shyft Intuiti Travel System with a Revolve180 LiteMax NXT infant car seat. The car seat was manufactured on 03/27/2025, model TS100212542. I was notified by Amazon that the car seat was recalled due to a calibration issue with the level indicator that caused the product not to meet applicable federal performance requirements. I contacted Evenflo ParentLink regarding the recall and was informed that Evenflo would provide only a repair kit and would not provide a replacement or refund. Evenflo's proposed interim solutions include using the car seat without the rotating base, using a non-rotating base, or using the rotating base with a modified recline or a load leg. These alternatives do not provide an equivalent remedy for the product I purchased. I specifically purchased this infant seat because the base is designed to rotate. Both parents in our household have back problems, and the rotating feature was an important safety and usability consideration when placing our infant into the seat. Removing the rotating functionality or changing the installation configuration does not provide an equivalent product. Because I did not consider the proposed alternatives acceptable for safely and practically transporting my infant, I purchased a replacement rotating car seat. Amazon ultimately agreed to refund the recalled travel system and arrange pickup of the product. I am submitting this complaint because I believe the recall remedy should be evaluated to determine whether it provides an effective and reasonably equivalent solution to affected consumers, particularly when the recalled product's primary functionality is lost under the proposed interim solutions. I am not reporting a crash or injury.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Huntsville , AL

    Approximately 3 miles from my residence my car display flashed "Reduced Engine Power" and slowed down. When I reached a stop sign and tried to stop, my brakes were stiff and I was unable to stop. I went through the stop sign. I continued to my residence at 10mph and backed into a parking space with a curb to help stop my vehicle. I turned the car off and called a mechanic to come look at my car. I explained the events and let him know it would not start. He checked the codes after hooking it up. The error codes were for Cam shaft and crank shaft, etc. I was instructed to not try and start the car because further damage could occur and it would need the camshaft pulled to determine the extent of damage.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Charleston, WV

    The contact owns a 2018 GMC Terrain. The contact stated that while her son was driving 45 MPH, the brake pedal was firm while depressed. There was no warning light illuminated. Due to the failure, excessive force was needed on the brake pedal to stop the vehicle. The contact was able to drive the vehicle to the residence. The following day, the vehicle was taken to an independent mechanic. The mechanic diagnosed the vehicle with an inoperable vacuum pump that was shredded and needed to be replaced. The manufacturer was notified of the failure and informed the contact that the VIN was not under recall. The contact was then referred to the NHTSA Hotline for assistance. The vehicle was not yet repaired. The failure mileage was approximately 117,000.

    Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE
  • 2018 GMC TERRAIN
    - Southgate, MI

    While driving my 2018 GMC Terrain, the vehicle suddenly displayed an “Engine Power Reduced” warning and the brakes became extremely hard to press. The vehicle experienced a sudden loss of normal power-brake assist while it was in motion, creating a serious safety risk because significantly greater pedal force was required to stop the vehicle. I was able to pull over safely. After stopping, the vehicle would crank but would not start. The vehicle was towed to a GMC dealership for inspection. The dealership documented that the vehicle had a suspected failed/broken vacuum pump, a damaged exhaust camshaft, and a damaged exhaust camshaft actuator. The dealership subsequently documented that the engine was severely sludged and stated that the sludge caused the vacuum pump to fail, which then caused the exhaust camshaft to twist and damage the exhaust camshaft actuator. The dealership’s written diagnosis recommends replacement of the exhaust camshaft, exhaust camshaft actuator, vacuum pump, and associated one-time-use parts. The dealership has also documented diagnostic trouble codes P0014 and P0017. The failed vacuum pump and related components should be available for inspection upon request. The vehicle has been inspected by a GMC dealership, which has documented the suspected vacuum pump failure and resulting engine damage. The sudden loss of power-brake assist occurred while the vehicle was being driven and created a potentially dangerous loss of braking capability. I am reporting this because I believe the failure of the vacuum pump and resulting loss of brake assist may represent a safety-related defect requiring investigation, particularly because the vehicle experienced a hard brake pedal without prior warning.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Hometown, IL

    The contact owns a 2018 GMC Terrain. The contact stated that while driving at an undisclosed speed, the brake pedal was depressed; however, the vehicle failed to stop as intended. The contact stated that the brake pedal was abnormally firm. The brake pedal was depressed to the floor, and the vehicle came to a stop. The check engine warning light was illuminated. The vehicle was towed to the dealer. The vehicle was not diagnosed. The contact referenced an unknown recall; however, the VIN was not associated with a recall related to the failure. The manufacturer was not made aware of the failure. The failure mileage was approximately 95,300.

    Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE
  • 2018 GMC TERRAIN
    - nazareth, PA

    Vehicle would slowly roll even when break is applied. It was confirmed by the service center that the break booster vacuum pump was only reading 8 when it should be at 27. It was not making enough pressure. The vehicle would not stop when break was applied.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Bensalem, PA

    The vehicle has had regular maintenance, oil change, and inspection including the brakes. My boyfriend is visiting me in [XXX] from the [XXX]. OnXXX while driving the vehicle the engine started. Making a ticking noise especially during idle and when accelerating in idle. About 15 minutes after the ticking stopped and all of a sudden there's a complete loss of breaks they locked up and the driver was unable to efficiently stop while going down a hill Road. Driver had to use the emergency brake to make the other brakes release and then the brakes from there would not work even though you could stomp on them stand on top of them there was no breaking power anymore. Vehicle was brought into a GMC dealership on the following Monday where they confirmed the issue was a failed vacuum pump connected to the engine and camshaft which is a known safety issue to GMC as part of an ongoing open case they had specialty coverage and bulletins regarding the Tahoe and Sierra but neglected to include the terrain on this issue. Cold the GMC manufacturer in both [XXX] and [XXX] to try and get cost assistance and specialty coverage as the vehicle as well under the mileage requirements but have been giving the push around and zero assistance. The risk to the drivers and passengers lives was significant as we were on the highway for1.5 hrand thankfully the brake lost didn't happen in full during that time. The repairs were completed and paid for in full by the client which should have been covered by the dealership and we are looking for cost recuperation and are now being ignored. Receipts are here to substantiate the claim. The ABS light is no longer on there was no warnings on the vehicle showing any issues or any codes as OnStar was called and diagnostics were received and the diagnostics came back clear prior to this happening, and following the break failure. Lack of codes and warnings is life-threatening and serious. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Caruthersville , MO

    Vacuum pump that supplies vacuum to brake booster failed without any warnings beforehand leaving us without the ability to stop. Luckily was able to avoid an accident.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Marquette, MI

    While traveling on the highway in traffic, brakes became very stiff when depressed after attempting to slow down to exit. Was able to put full bodyweight into the brake pedal to slow enough to exit and navigate to the gas station right off the exit. Had to roll stop signs and unsafely navigate traffic because brakes were not working. Service Brake System warning light came on after the incident.

    Source: NHTSA WEB SITE
  • 2018 GMC TERRAIN
    - Marion, IL

    The contact owns a 2018 GMC Terrain Denali. The contact stated while the contact's daughter was driving, the brake pedal was depressed, however the vehicle failed to stop as intended. In addition, the contact stated that the brake pedal was unusually hard when depressed. The vehicle was taken to the dealer where the vehicle was purchased. The contact stated that the service brake vacuum pump failed while the vehicle was at the dealer. The vehicle was diagnosed with a failed service brake vacuum pump and a failed engine. The contact was informed that the service brake vacuum pump, the CAM Shaft and the engine needed to be replaced. The vehicle was repaired. The contact stated that the failure was a known failure of the vehicle. The manufacturer was not made aware of the failure. The failure mileage was approximately 260,000.

    Source: HOTLINE VEHICLE OWNERS QUESTIONNAIRE