2018 GMC Terrain problems & reliability
220 owner complaints filed with NHTSA for the 2018 GMC Terrain, alongside 5 safety recall campaigns. Last verified Sep 21, 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 components.
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 → | 68 | 31% |
| Engine → | 53 | 24% |
| Power Train → | 41 | 19% |
| Electrical System → | 35 | 16% |
| Unknown / Other | 34 | 15% |
| Air Bags → | 14 | 6% |
| Service Brakes, Hydraulic → | 13 | 6% |
| Fuel/propulsion System → | 12 | 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%.
All 30 reported components →Common symptoms owners describe
Keyword analysis of complaint narratives; one complaint can describe several symptoms.
Mileage when problems occurred
Among the 83 complaints that included a usable odometer reading, the median reported incident mileage was 25,000 miles (middle 50% between 5,550 and 67,542 miles).
Complaints by incident year
What owners report
“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…”
Service Brakes, Hydraulic · filed Sep 14, 2026
“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…”
Carry Handle, Shell, Base · filed Aug 28, 2026
“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…”
Engine · filed Aug 24, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
1,344 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2018 GMC Terrain. The 10 most recent:
This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
PIP4902W · Service Bulletin/Repair Instructions · issued Sep 4, 2026
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
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.
- · Among complaints with usable mileage, the median reported incident mileage was 25,000 miles. This does not predict when a particular vehicle will develop a problem.