Table 1 shows two common lane departure related problems of the 2026 GMC Terrain.
| Problem Category | Number of Problems |
|---|---|
| Warning problems | |
| Assist problems |
Two issues here. First is that the car will give a danger warning when nothing is there. Sometimes goes as far as slamming on my breaks. Both in drive and reverse. Second is the lane keep assist. It’s like it is working backwards. I turned this all off because it would jerk me out of the lane and into the other lane or off to the sides of the road.
A failing telematics module on your 2026 GMC Terrain is causing network corruption, leading to an erratic speedometer and loss of driver assistance systems while driving.