There are 1 owner-reported driver assist & adas complaints for the 2021 GMC Terrainin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Automatic Emergency brakes have unnecessarily or prematurely activated on 2 separate occasions causing my car to stop very abruptly which has resulted in Neck, Shoulder and back pain. I have been very lucky in the recent past and today that a vehicle was not directly behind me. The seat vibrated first when it sensed the car ahead was breaking. When I started to break, the emergency break kicked in. I did not report this the first time because I thought the car was doing what it was supposed to do. Today was unnecessary. No accident and no police report. I do plan on telling the dealership.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026