2018 GMC Terrain Common Problems & Defect Telemetry
Authoritative defect intelligence synthesized from 216 verified NHTSA owner complaints, 5 federal safety recalls, and interquartile failure mileage telemetry.
The 2018 GMC Terrain receives a 4.5/10 MazicBay Reliability Index based on 216 verified NHTSA federal complaints and 5 safety recalls. The primary reported failure mode is Service Brakes, ABS Actuator & Master Cylinder Reports with a median failure point at 51,138 miles (IQR: 20,000 – 107,000 mi). Out-of-warranty repairs benchmark at $350 – $1,100 .
25.4 complaints / 10k sold
Verified US federal records
Crash, fire & stall audit
5 Active / Free Remedies
2018 Terrain Failure Distribution by Vehicle Subsystem
Top Reported Problem Clusters (7)
Service Brakes, ABS Actuator & Master Cylinder Reports
- Spongy or hard brake pedal travel
- ABS / Brake warning light illuminated
- Extended stopping distance / pedal vibration
“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 ...”
“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...”
“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.”
Engine Stalling, Oil Consumption & Cooling Defect Reports
- Engine sudden stall / hesitation while driving
- Abnormal oil burning / consumption
- Check Engine Light (MIL) flashing
- Engine overheating / coolant loss
“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 ...”
“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...”
“The vehicle has had regular maintenance, oil change, and inspection including the brakes. My boyfriend is visiting me in ... from the .... OnXXX while driving the vehicle the engine started. Making a ticking noise especially during idle and when accelerating in idle. About 15 ...”
Transmission Hesitation, Hard Shifting & Slipping Reports
- Hard gear shifts / delayed engagement into Drive/Reverse
- Transmission shudder / jerking under acceleration
- Transmission slipping between gears
“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 assi...”
“Vehicle will not shift out of park, despite replacing the valve body, putting in a new battery, and transmission fluid. It has been this way since mid January. The codes don’t make sense and there is no current recall, nor have we had this vehicle for very long. It has 48,000 ...”
“The contact owns a 2018 GMC Terrain. The contact stated that while driving at various speeds, there was an abnormal grinding sound coming from the vehicle while transitioning to 4WD. The contact continued driving and the driving sound became more frequent while shifting into 4...”
Electrical Parasitic Drain, Infotainment & Harness Reports
- Unexplained battery drain after sitting overnight
- Infotainment display / instrument cluster blackouts
- Accessory malfunction / alternator fault warnings
“Vehicle will not shift out of park, despite replacing the valve body, putting in a new battery, and transmission fluid. It has been this way since mid January. The codes don’t make sense and there is no current recall, nor have we had this vehicle for very long. It has 48,000 ...”
“The infotainment system will just randomly start going haywire and when it happens, you cannot use the touchscreen. It will try to randomly delete app icons such as the camera, it will try to delete connected phones, it will try to delete radio favorites and it will move app i...”
“The contact owns a 2018 GMC Terrain. The contact stated that the transmission was shifting gear erratically. The contact stated that the doors were locking and unlocking independently, and the instrument cluster was blank. There was an abnormal beeping sound coming from the ve...”
Electric Power Steering Assist & Suspension Noise Reports
- Sudden loss of electric power steering assist
- Steering wheel pull or highway wander
- Clunking / knocking noise over bumps
“The contact owns a 2018 GMC Terrain. The contact stated that while driving at various speeds, there was an abnormal grinding sound coming from the vehicle while transitioning to 4WD. The contact continued driving and the driving sound became more frequent while shifting into 4...”
“The contact owned a 2018 GMC Terrain. The contact stated that while driving and nearly coming to a complete stop in the right lane, another vehicle driving approximately 40-50 MPH crashed into the rear of the vehicle, causing the contact to hit her face against the steering wh...”
“The headliner fabric detached somehow from the panoramic track causing the fabric to hang down obstructing the rear and back window view causing a safety hazard. The automatic forward collision alert will come on for no reason since this has happened. The problem has not been ...”
Airbag Occupant Detection & Inflator Defect Reports
- SRS Airbag warning lamp illuminated
- Passenger occupant classification sensor failure
- Seat belt retractor lockup
“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”
“My car said to me this not that there is something wrong with the Service Safety Restraint system! It was fine last night when I got home! I just bought this car a month ago and everything was fine and now my air bag light is on and will not go off!”
“The contact owns a 2018 GMC Terrain. The contact stated while driving at an undisclosed speed, the air bag and ABS warning lights illuminated. The vehicle was taken to Auto Zone to be diagnosed. The vehicle was diagnosed with air bag failure. The contact was informed that the ...”
Fuel Pump Pressure Loss & Fuel Delivery Defect Reports
- Sudden loss of propulsion power at highway speeds
- Extended engine cranking / failure to restart
- Fuel odor near fuel tank / engine bay
“My check engine light comes on intermittently, since March 2024, after having Cabin & Engine air filters replaced. Each time, I’m told it is code P0171. This has happened too many times for my comfort. Usually, it happens around the time my gas gets below 1/2 tank or after I f...”
“The contact owns a 2018 GMC Terrain. The contact stated while driving at approximately 65 MPH, the check engine warning light illuminated, and the vehicle decelerated to 20 MPH. Additionally, the message "Service Emissions" was displayed. The vehicle was taken to the local dea...”
“The contact owns a 2018 GMC Terrain. The contact stated that while driving at approximately 35 MPH going over a hill, the brake pedal was depressed but was firm and failed to depress as needed. The engine power reduced message was displayed and flashed on and then off. The bra...”
Official NHTSA Safety Recalls (5)
AIR BAGS: AIR BAG/RESTRAINT CONTROL MODULE
Summary: General Motors LLC (GM) is recalling certain 2018 GMC Terrain vehicles. The sensing diagnostic module (SDM) that senses a crash and deploys the necessary air bags may not power down correctly when the vehicle is shut off, causing it to be inoperative when the vehicle is restarted.
SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:DISC:CALIPER
Summary: General Motors LLC (GM) is recalling certain 2018-2019 Chevrolet Equinox, Impala, Cruze, Volt and Bolt EV vehicles, GMC Terrain vehicles, Buick Lacrosse and Regal vehicles, Cadillac XTS and XTS Professional vehicles and 2018 Chevrolet Malibu vehicles. The rear brake caliper pistons may have an insufficient coating causing gas pockets to form, potentially reducing rear brake performance.
FUEL SYSTEM, GASOLINE:DELIVERY:FUEL PUMP
Summary: General Motors LLC (GM) is recalling certain 2015-2018 GMC Canyon, 2016-2017 Buick Envision, 2016-2018 Chevrolet Colorado and Malibu, 2017-2018 GMC Acadia, 2018 Buick LaCrosse, Cadillac ATS, Chevrolet Equinox, and GMC Terrain vehicles. The high pressure fuel pump may detach from its mounting flange, possibly resulting in the pump damaging the high pressure fuel line.
POWER TRAIN:AUTOMATIC TRANSMISSION
Summary: General Motors LLC (GM) is recalling certain 2018-2019 Chevrolet Cruze and Buick LaCrosse, 2018-2020 Chevrolet Equinox, Chevrolet Traverse and GMC Terrain, 2018 Chevrolet Malibu, 2019-2020 Buick Encore, Buick Enclave, Cadillac XT4, Chevrolet Blazer and GMC Acadia, and 2020 Cadillac XT6 vehicles. The start/stop accumulator endcap may have missing bolts.
POWER TRAIN:DRIVELINE:DRIVESHAFT
Summary: General Motors LLC (GM) is recalling certain 2018 Chevrolet Equinox and GMC Terrain vehicles and 2017-2018 GMC Acadia vehicles. The right front intermediate driveshaft may fracture and separate while driving.
Pre-Purchase Inspection Checklist for 2018 GMC Terrain
Before purchasing a used 2018 GMC Terrain, perform the following targeted inspections based on reported federal defect patterns:
Scan the OBD-II port under the dash for pending freeze-frame codes (e.g. P0300 misfires, P0087 fuel rail pressure, P0420 catalytic efficiency).
Test vehicle at low-speed stop-and-go and highway merges. Check for delayed reverse engagement or gear shift shudder between 2nd and 3rd gears.
Verify that all 5 NHTSA safety recall campaigns have been performed by an authorized dealership using the VIN.
Ensure the instrument cluster, center screen, and auxiliary charging ports operate with stable 12.0V–14.4V alternator voltage.
Defect & Reliability Q&A: 2018 GMC Terrain
Is the 2018 GMC Terrain a reliable used car?
The 2018 GMC Terrain earns a 4.5/10 MazicBay Reliability Index based on 216 federal owner reports. Vehicles maintained under factory service schedules exhibit strong longevity past 150,000 miles.
What is the most frequent defect reported on the 2018 GMC Terrain?
The leading complaint category is Service Brakes, ABS Actuator & Master Cylinder Reports, with a median failure point around 51,138 miles (IQR: 20,000 – 107,000 mi).
Are there free recall repairs available for the 2018 GMC Terrain?
Yes, the NHTSA records 5 safety recall campaign(s) for this model year. All safety recalls are performed 100% free of charge by authorized franchise dealerships regardless of vehicle warranty status.