2018 GMC Terrain

223 complaints on file, page 1 of 12.

1. Filed Sep 30, 2026Failure Sep 28, 2026Greenwich, NYEngine, Service brakes, Unknown or other

   Without any type of warning, I was driving down the road when my car started making a knocking/ticking type noise then my engine light came on. I attempted to hit my brakes and stop, and I had no control. There was no brakes without pushing it all the way to the floor it was very hard to get my car to stop. I managed to get off the road and into a parking lot and now told that I have $5000 worth of repairs, including the vacuum pump, camshaft timing and guides. After reading information I see there is complaints filed regarding this failed vacuum pump and I would just like to report this.

   NHTSA complaint 11767937
2. Filed Sep 25, 2026Failure Sep 5, 2026Northwoods, MOSteering, Suspension

   Dear [Manufacturer], I am writing to report a serious safety concern with my [year, make, model]. A bolt from the idler arm/undercarriage came off after becoming severely rusted. I had the vehicle inspected by a repair shop, but they could not determine why the bolt failed or why it had rusted to this extent. This is extremely concerning because a failure of this component while driving could potentially result in loss of control and a serious accident. I am asking the manufacturer to investigate this issue and determine whether this is a known defect or corrosion-related problem. Please let me know if you would like to inspect the vehicle or failed component. I look forward to your response. Sincerely, [Your Name] [Year/Make/Model] [VIN] Sent from my iPhone

   NHTSA complaint 11767009
3. Filed Sep 24, 2026Failure Dec 15, 2024Phelps, NYFuel system, Gasoline

   The contact owns a 2018 GMC Terrain. The contact stated that while the vehicle was parked in the garage at the residence, there was fuel leaking from the vehicle from the fuel line. The contact stated that the fuel pump was replaced. There was a strong gasoline odor coming from the vehicle. The contact associated the failure with NHTSA Campaign Number: 18V358000 (Fuel System, Gasoline); however, the VIN was not included in the recall. The dealer was contacted by phone and made aware of the failure but stated that the repair was not covered because the VIN was not included in the recall.

   NHTSA complaint 11766614
4. Filed Sep 14, 2026Failure Sep 11, 2026116,000 milesWest Berlin, NJService brakes, Hydraulic

   The contact owns a 2018 GMC Terrain. The contact stated that while driving 20 MPH, the brake pedal was firm and the "Service Brake Assist" message was displayed on the instrument panel. The contact used excessive force to depress the brake pedal while stopping the vehicle. The vehicle was driven to the destination and parked. The dealer was notified of the failure and informed the contact that the vehicle was not included in a vacuum pump recall. The vehicle was not diagnosed or repaired. The vehicle was scheduled for repair with an independent mechanic. The failure mileage was approximately 116,000.

   NHTSA complaint 11764014
5. Filed Aug 28, 2026Failure Aug 14, 2026Katy, TXCarry handle, Shell, Base, Tether

   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.

   NHTSA complaint 11760395
6. Filed Aug 24, 2026Failure Aug 19, 2026Huntsville, ALEngine, Service brakes, Unknown or other

   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.

   NHTSA complaint 11759068
7. Filed Aug 21, 2026Failure Aug 19, 2026117,000 milesCharleston, WVService brakes, Hydraulic

   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.

   NHTSA complaint 11758514
8. Filed Aug 10, 2026Failure Jul 29, 2026Southgate, MIEngine, Service brakes

   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.

   NHTSA complaint 11755920
9. Filed Aug 3, 2026Failure Aug 2, 202695,300 milesHometown, ILService brakes, Hydraulic

   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.

   NHTSA complaint 11754433
10. Filed Jul 22, 2026Failure Jul 22, 2026nazareth, PAService brakes

    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.

    NHTSA complaint 11752244
11. Filed Jul 17, 2026Failure Jul 11, 2026Bensalem, PAEngine, Automatic emergency braking, Service brakes

    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)

    NHTSA complaint 11751119
12. Filed Jun 5, 2026Failure Jun 3, 2026Caruthersville, MOService brakes

    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.

    NHTSA complaint 11742410
13. Filed May 25, 2026Failure May 24, 2026Marquette, MIService brakes

    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.

    NHTSA complaint 11739875
14. Filed May 23, 2026Failure May 22, 2026Covington, GAFuel/propulsion system

    Gas leaking from the hood. High pressure fuel pump

    NHTSA complaint 11739681
15. Filed May 12, 2026Failure Mar 15, 2026260,000 milesMarion, ILEngine, Service brakes, Hydraulic

    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.

    NHTSA complaint 11737294
16. Filed Mar 23, 2026Failure Mar 18, 2026Waterloo, NYService brakes

    We just got off the bus thruway and my brakes pedal got hard to press and it was hard to stop car I had to push on brake dry hard to get the car to stop it was jarring and o had to get my some and o to a safe place. Garage said it’s brake assist and he researched there’s is an active law suit against GM bc lots of Moses and models have this issue although they claim to know nothing about it

    NHTSA complaint 11726554
17. Filed Mar 16, 2026Failure Mar 13, 2026West Mifflin, PAAir bagsCrash2 injured

    My car was t-boned on the driver side and no airbags deployed. The outer door and window exploded with the force. We were also hit from behind

    NHTSA complaint 11724819
18. Filed Mar 6, 2026Failure Mar 6, 2026Somersworth, NHUnknown or other

    The control knob that controls AWD, 2WD,Off-road, and 4 x4 AWD. Just stopped working. Stuck on 2WD mode. I did have it checked for any codes, even though, there is NO check engine light is on.

    NHTSA complaint 11722587
19. Filed Mar 3, 2026Failure Feb 27, 2026245,000 milesDetroit, MIPower train

    The contact owns a 2018 GMC Terrain. While attempting to shift to reverse(R) out of a parking spot, the message “Transmission Unable to Shift” was displayed on the instrument panel, and the transmission was unable to shift into reverse(R). The contact called for tow truck assistance. The vehicle was unable to shift into neutral (N). The contact stated that prior to the transmission failure, the “Service Transmission Soon” message was displayed. The vehicle was towed to a local dealer to be diagnosed, and it was determined that the transmission had failed and needed to be replaced. The vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 245,000.

    NHTSA complaint 11721631
20. Filed Mar 2, 2026Failure Feb 27, 2026Gray, GAService brakes

    Faulty Brake Vacuum Pump!!!! 2018 GMC Terrain @ 119254 miles--- NO warning! Brakes were hard to press, did not work and I rolled into ditch to prevent an accident. I see hundreds of people with same issue now that I Am having to research. This was very scary. I was told it was as a brake booster pressure sensor. But that was not the problem. It is the brake vacuum pump. This is so dangerous. Why is GMC not correcting this issue? This is insane. GM issued multiple technical service bulletins on vacuum and booster issues starting in 2017. Why hasn't anything been done?

    NHTSA complaint 11721477