2020 GMC Acadia Reliability Report

Thermostat failure is the main issue. It sets codes P01F0 or P0128, drops the temperature gauge to cold, and often brings up the steering assist warning. One failure came under 55,000 miles. Early on the symptoms can come and go without setting a code, which makes diagnosis slow. Other reports describe a cracked catalytic converter leaking exhaust into the cabin at under 60,000 miles, and leaking rear heater lines that require replacing the whole dealer-only assembly.

The engine loses power and shuts off while driving, sometimes after violent jerking at highway speed, and may not restart right away. The fuel gauge can read wrong, showing half or three-quarters full after a fill-up, or running dry while still showing range left. Fuel pump module failure causes a no-start, with one vehicle needing a second replacement around 50k miles. A stall at speed puts the car at risk in traffic. Only a few complaints are on file.

The electronic parking brake engages on its own, sometimes while the car is moving, bringing it to a sudden stop with no warning. One case happened at 15 mph on a nearly new vehicle. Other owners say the parking brake sets itself when parked on an incline and won't release until the car is put in gear. Dealers have been unsure of the cause. An unexpected hard stop raises the risk of a rear-end collision.

Automatic emergency braking slams on the brakes with nothing ahead, on the road and when pulling into a garage. Some drivers see a red pedestrian warning on the head-up display just before the car nose-dives. The front camera can also go dark, which disables collision alerts and adaptive cruise control, and restarting doesn't bring it back. Phantom braking puts the car at risk of being rear-ended by following traffic.

Front seat belts fail to latch on the first few tries or come unlatched while the car is moving. In one case both front belts were affected, and the dealer said they needed replacement at about 35,000 miles. An unlatched belt leaves the occupant unprotected in a crash. Only 3 complaints are on file, and one gives no detail.

No deployment occurs in a serious rear-end collision described in one crash report, which involved 2 injuries and a fractured front passenger seat. A second crash report describes the vehicle speeding up on its own at low speed and hitting a wall, and the air bags did deploy in that one. The third lists an air bag fault among many warning lights appearing at once. Two of the 3 complaints involve crashes, but the total count is small.

The side blind zone alert system shuts off and shows a "temporarily unavailable" or service message, then stops working. The failure happens often and can come back after a dealer repair. Drivers who rely on blind spot warnings lose them without notice. Both complaints on file describe this same blind spot fault.