2021 GMC Terrain Other or unknown Problems
- Complaints
- 4about this part
- Share
- 11%of 36 total for the year
- Median mileage
- —not reported
- Trend
- Not enough dataFewer than 15 complaints, too few for a reliable trend.
NHTSA recorded 4 complaints about the other or unknown of the 2021 GMC Terrain, 11% of the 36 complaints for this model year.
Fewer than 15 complaints name this part, so treat the figures as a rough indication only.
Example complaints
Selected from NHTSA records; personal details are removed. They are consumer reports, not findings.
“Constantly have water leaking into spare tire compartment, back seat floors and passenger floor. Mold/mildew smell coming through vents. Have had drains lines cleaned out, and still recurring having this issue. Unknown where leak is coming from. This is a serious health risk.”
NHTSA complaint #11678054, filed 2025-08“There is a rattle in the b pillar/roof area. They have attempted to fix it 4 or more times by adding adhesive between layers of metal. The fix that other dealerships have done per reading online involves cutting through metal. This would affect the integrity of the body/ frame of the car.”
NHTSA complaint #11478411, filed 2022-08“The contact owns a 2021 GMC Terrain. The contact received notification of NHTSA Campaign Number: 23V339000 (Child Seat); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The dealer was contacted and informed the contact that the vehicle would not be inspected or repaired. The manufacturer was made aware of the issue. The contact had not experienced a failure.”
NHTSA complaint #11696797, filed 2025-10Related service bulletins
- 11037555Sep 26, 2026This PI provides Diagnostics tips on how the LIN bus works and how to diagnosis it.
- 11037253Sep 4, 2026This preliminary information advises a dealer on how to email GDS2 session logs into Technical Assistance.
- 11036392Aug 20, 2026This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
- 11035340Jul 21, 2026PI to help diagnose A/C concern
- 11034769Jun 23, 2026This Preliminary information communicates an issue with an OTA pending message still displayed after an OTA event and how to reset/clear the message.
- 11032764May 11, 2026Pi created to provide GM dealers with information on gathering information for projection issue
- 11032763May 11, 2026This Preliminary information communicates to dealer to perform a MEC reset for wireless projection issues
- 11031282Apr 8, 2026This preliminary information announces the end of an engineering investigation into a brake pad noise.
- 11030974Apr 1, 2026This preliminary information communicates information about how to determine if a wheel and tires size change is available.
- 11030360Mar 27, 2026This 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.
Other or unknown: other model years
| Year | Complaints | Share of year |
|---|---|---|
| 2026 | 9 | 27% |
| 2025 | 2 | 15% |
| 2024 | 12 | 23% |
| 2023 | 7 | 17% |
| 2022 | 9 | 15% |
| 2021 | 4 | 11% |
| 2020 | 36 | 18% |
| 2019 | 21 | 11% |
| 2018 | 36 | 16% |
| 2017 | 20 | 15% |
| 2016 | 13 | 9% |
| 2015 | 21 | 7% |
| 2014 | 16 | 5% |
| 2013 | 27 | 7% |
| 2012 | 37 | 10% |
| 2011 | 34 | 9% |
| 2010 | 18 | 6% |
Other parts of the 2021 GMC Terrain
10 complaintsBrakes
8 complaintsTransmission and drivetrain
8 complaintsElectrical system
7 complaintsFuel system
4 complaintsForward collision avoidance
3 complaintsEngine cooling
2 complaintsLane departure
2 complaintsSuspension
2 complaintsAir bags
1 complaintsSteering
1 complaintsVehicle speed control
1 complaints
← All problems reported for the 2021 GMC Terrain
About this data. Data from NHTSA (ODI) complaints, recalls, TSBs and investigations, updated Oct 27, 2026. Complaints are unverified consumer reports and may be duplicated or inaccurate.
To check a specific vehicle for open recalls, use its VIN at nhtsa.gov/recalls. Methodology