2021 GMC Terrain problems & reliability
34 owner complaints filed with NHTSA for the 2021 GMC Terrain, alongside 2 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.
4 complaints report injuries (4 injured).
Federal crash records (FARS 2020–2023): 2021 GMC Terrain vehicles were involved in 15 fatal crashes with 6 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 |
|---|---|---|
| Engine | 8 | 24% |
| Power Train | 8 | 24% |
| Service Brakes | 8 | 24% |
| Electrical System | 7 | 21% |
| Forward Collision Avoidance | 3 | 9% |
| Unknown OR Other | 3 | 9% |
| Engine and Engine Cooling | 2 | 6% |
| Fuel/propulsion System | 2 | 6% |
| Fuel System, Gasoline | 2 | 6% |
| Lane Departure | 2 | 6% |
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.
Complaints by incident year
What owners report
“Driving on the Garden state parkway on Sunday night June 28, 2026 I proceed to cross over the ratitan bridge. There was traffic as I was going down the bridge at 70 miles an hour. When I applied the brakes the car would not stop. I had two 6 years old in the backseat. I applied 2 feet to the brake pedal and it was…”
Service Brakes · filed Jul 1, 2026
“Formal Safety Complaint – 2021 GMC Terrain Brake Failure Vehicle: 2021 GMC Terrain Incident Location: Garden State Parkway (NJ) Speed: Approximately 65 mph Incident Description While driving northbound at highway speed, I attempted to change lanes and apply my brakes. When I pressed the brake pedal, it became…”
Service Brakes · filed Jul 1, 2026
“Automatic transmission solenoid control valve body got stuck open and ruined the whole transmission. This has been a reoccurring problem with these vehicles. Image is from a code read. Issue was confirmed by Gastorf Chevrolet, and an independent transmission shop.”
Power Train · filed Apr 29, 2026
Verbatim excerpts from complaints filed with NHTSA. Reports are not independently verified.
Technical service bulletins
693 manufacturer communications (TSBs, service campaigns, warranty extensions) are on file with NHTSA for the 2021 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 an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.
PIT5966F · Service Bulletin/Repair Instructions · issued Jun 23, 2026
Pi created to provide GM dealers with information on gathering information for projection issue
PIC6423A · Service Bulletin/Repair Instructions · issued May 11, 2026
This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
PIC6551B · Service Bulletin/Repair Instructions · issued May 11, 2026
This preliminary information announces the end of an engineering investigation into a brake pad noise.
PIT5812G · Service Bulletin/Repair Instructions · issued Apr 8, 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
Improvements to OnStar functionality.
N25-250552 · Over The Air · issued Mar 21, 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
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 2021 GMC Terrain has 2 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 2021 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.