2018 GMC Terrain problems & reliability
215 owner complaints filed with NHTSA for the 2018 GMC Terrain, alongside 5 safety recall campaigns. Last verified Aug 7, 2026. Complaints are unverified reports submitted by owners to the federal Office of Defects Investigation.
Each complaint is counted once (by NHTSA case number), even when it names several vehicles.
7 complaints report injuries (12 injured).
Federal crash records (FARS 2020–2023): 2018 GMC Terrain vehicles were involved in 49 fatal crashes with 21 occupant deaths. Involvement counts are not adjusted for how many are on the road and do not imply fault or a vehicle defect.
Most reported problems
| Component | Complaints | Share |
|---|---|---|
| Service Brakes | 66 | 31% |
| Engine | 51 | 24% |
| Power Train | 41 | 19% |
| Electrical System | 35 | 16% |
| Unknown OR Other | 33 | 15% |
| Air Bags | 14 | 7% |
| Fuel/propulsion System | 12 | 6% |
| Service Brakes, Hydraulic | 11 | 5% |
| Forward Collision Avoidance | 8 | 4% |
| Vehicle Speed Control | 8 | 4% |
Component groups as classified by NHTSA. A complaint can name more than one component, so shares may sum to more than 100%.
Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Mileage when problems occurred
Half of the failures with a reported odometer reading occurred by 22,000 miles (middle 50% between 5,100 and 65,000 miles), based on 81 complaints that included mileage.
Complaints by incident year
What owners report
“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…”
Service Brakes, Hydraulic · filed Aug 3, 2026
“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.”
Service Brakes · filed Jul 22, 2026
“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…”
Service Brakes · filed Jul 17, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
1,343 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2018 GMC Terrain. The 10 most recent:
PI to help diagnose A/C concern
PIT5099J · Service Bulletin/Repair Instructions · issued Jul 21, 2026
This preliminary information communicates information about how to determine if a wheel and tires size change is available.
PIT3271Q · Service Bulletin/Repair Instructions · issued Apr 1, 2026
This preliminary information discusses a condition that may arise from the drivers window switch sending an errant message causing the vehicle to enter manual fob learn mode.
PIT5992B · Service Bulletin/Repair Instructions · issued Mar 27, 2026
This Preliminary information communicates the steps on how to save a GDS2 Session Log and upload to a Technical Assistance Case in CX Connect.
PIP6104 · Service Bulletin/Repair Instructions · issued Mar 9, 2026
This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIP4902V · Service Bulletin/Repair Instructions · issued Mar 9, 2026
This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIP4902U · Service Bulletin/Repair Instructions · issued Jan 8, 2026
This Preliminary Information communication provides information to the technician about vehicles that have had multiple repair attempts that are being performed on customer’s vehicles that exhibit vibration conditions…
PIT5214G · Service Bulletin/Repair Instructions · issued Nov 20, 2025
New Vehicle Monitoring Programs Section in IVH
13598 · Other · issued Sep 9, 2025
This preliminary information advises technicians the heater hose clamps are one time use only.
PIT5578E · Service Bulletin/Repair Instructions · issued Aug 27, 2025
This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIP4902T · Service Bulletin/Repair Instructions · issued Aug 14, 2025
TSBs are repair guidance manufacturers send to dealers — they are not recalls and repairs are not automatically free. Full documents are available on NHTSA’s site.
Safety recalls
The 2018 GMC Terrain has 5 NHTSA recall campaigns — recall repairs are free at franchised dealers regardless of the vehicle’s age.
Check whether your specific vehicle is affected
Recall campaigns often cover only certain VIN ranges. Enter your VIN on the official NHTSA site to confirm whether your vehicle is included and whether the repair is still open.
Check VIN on NHTSA →Buying a used 2018 GMC Terrain?
- · Decode the seller’s VIN with our free VIN decoder to confirm the exact year, engine and trim.
- · Check for unrepaired recalls by VIN on NHTSA’s official lookup — recall repairs are free.
- · Owners most often reported problems around 22,000 miles — budget accordingly if the car is approaching that mileage.