The Electronic Parking Brake has had multiple apparent malfunctions and one complete failure. On several occasions the parking brake failed to disengage completely with multiple warning dash lights illuminating. One such incident apparently self-corrected after being left parked overnight our semi-heated garage, with another incident only partially disengaged the parking brake with warning lights indicating a parking brake malfunction, and after driving two to three miles returning home the right rear brake was baking hot. The latest malfunction was a complete failure of the parking brake to engage at all, with the warning lights again illuminating and would be an obvious danger while parking. The vehicle is just over four years old and was two-and-a-half months out of warranty at the time of failure, and had/has 5,121 miles. It has now been waiting at the dealership for repairs for FOUR WEEKS, awaiting a Parking Brake Control Module which they cannot give any timeline for delivery or arrival. It is unknown if the Brake Control Module for the parking brake has any control or effect on the service brakes, so the vehicle is sitting at the dealership collecting dust, unusable to us.

- Edmonds, WA, USA

The car has an auto-stop feature however at times, when the car is stopped, the entire electrical and engine shuts down even while the car is in drive. The driver must restart the car and put the car into park and then back into drive. When the car restarts, several lights/messages turn on including "Service Transmission" and the "Service Parking Brake" message and parking break light. This is a safety and hazard issue as it has happened while in traffic on the freeway when at a standstill.

- San Jose, CA, USA

While on free way transmission stopped functioning properly after exit unable to move vehicles in gear. Dealer said it was a computer programming issue. Another instance 9 months later care emergency break would not dis engage even after shutting vehicle off and restarting several times that transmission would stop shifting soon received messages dealer said it was a computer programming error.

- Modesto , CA, USA

While driving on very slick roads on a highway, I attempted to brake the vehicle in preparation to making a left hand turn. I could not stop the vehicle. The wheels kept pushing me forward. I could feel the ABS pulsing but the vehicle would not stop. Luckily, no one was ahead of me or I would have hit the vehicle. It felt like the car was overriding my attempts to stop it. I wasn't just sliding on slick roads; the vehicle was actively pushing me forward.

- Ten Sleep, WY, USA

The E-break warning came on twice after releasing the E-break when parked, the warning came on shortly after pulling from a shopping center parking lot. The E-break light was flashing with the 'service light' active and a display notification of emergency break issues. Both of these two incidents happen after the last service update N19221631 was implemented back on 5/2020. The first one was present around September 2020 and the last one on 11/23/2020. I'm not sure if these two incidents happen due to the implementation of the service update but it seems coincidental that they happen shortly after the service update as this condition did not occurred before the service update. I do not drive my Buick much with only about 11K miles currently so it is not obvious the problem is due to age and usage unless there is a defect with the E-break product.

- Flower Mound, TX, USA

My car shifts itself into what seems to be a 'neutral' state and then revs up very loud. It also slams on its own brakes, thankfully each time has been at low speed. Today was the last straw. I am never getting in to that car again! as I was leaving a parking lot, my car slammed on its brakes, all kinds of rolling sounds under my feet. Then it stopped and hit hard to start going again. Lights on my dashboard going crazy... the guy who was backing up as I was going by, honked and yelled at me because he didn't know why I would stop like that. I should have been well past him, but my car decided we were stopping. So a little shaken and upset, but I carried on. This car has been doing that since 4000 miles. It is very stressful to get in that car as it is. I sat at the very next red light at the parking lot I had just left to turn left onto a majorly busy street. The light was red, when it turned green, I applied the gas after a and it surged so hard, it was as if I floored it all the way, but the pedal had not moved under my feet, but I could feel all kinds of 'action' happening under my feet. As the car went over the crosswalk paint, it screeched the tires and I almost hit the guy who was also making a left next to me as my car was thrusting forward with great speed and spinning tires, when the wheels caught the pavement I almost hit the guy next to me in his back door. I was honked at and scared. I waived my hands to try to say ' I don't know!' I didn't know what to do. The man followed me almost a mile to my work and when I got out of my car he called me every name you can think of. This car is really scaring me and I cannot drive it anymore. I am going to try to work with GMC to take it back. I shouldn't have to be terrified to go to the grocery store. This car has done similar things over the last two years but it has only gotten worse. Dealer "can't duplicate"

- Bermuda Dunes, CA, USA

The electronic parking brake has turned on 5 times now. 3 times, the car was in park and the emergency brake had turned on and would not turn off. The brake was not activated by anyone. Then it happened while driving. The vehicle was towed to a dealership. They worked on it and said it was fixed. This week while driving home from the grocery store the brake turned on again. The vehicle was again towed to the dealership.

- Holcombe, WI, USA

On 1/06/2020, while driving, the brakes locked up on my 2018 Buick Enclave.(mileage about 23,000) the vehicle has an electronic parking brake, which was off. Suddenly, the parking break light came on and service lights were illuminated. Fortunately, I was able to navigate to the side of the road, call GM and the car was towed to a local dealer. Several weeks earlier, upon starting, the parking brake light would not go off and the car would not move. After letting the car sit for a period of time, the light went off and I was able to drive the car. I went to the service department of a local dealer., explained what happened. They told me that I should come back in when it happened again, so they could read the code and noted they have not heard anything around the issue before and that no bulletins have been received from GM. As I understand, as of last evening, GM has not given them any direction. I believe this is a potentially serious safety issue and from an internet search, it appears others have encountered the same problem.

- Canton, OH, USA

Random activation of parking brake while the car is in drive. Most often occurs when on a slope and a low speed. Multiple incidents have occurred since purchase it has continued to get worse. The vehicle has been in for service many times with no resolution. I opened a case with GM on 9/12/2019 but they have not returned my calls or emails since 10/3/19. There has been several instances of this issue and was documented in a forum post that parallels our issue https://www.enclaveforum.net/threads/2018-avenir-electronic-emergency-brake-fault.22631/ 1) parking brake coming on at highway speeds as wife transported my daughter and some of her friends to the mall. At a red light, close to the mall my daughter commented on a smell. They pulled in the parking spot at the mall, my wife noticed the smell as well and when she exited the vehicle, the smell was overwhelming. 2) 2nd major incident while my wife was in a drive thru and the E-brake engaged (again, while the car was in drive). She had to place the car in park and it took 1-2 min before the car would disengage the E-brake. This incident convinced us that the problem was not human error and took it to dealership for service. 3) Sept 2019 - wife became stuck in parking lot when the E-brake engaged as she pulled in a parking spot (still in drive). She was aware that the E-brake had turned itself on but when she hopped in the car to leave, the E-brake was still engaged and wouldn't release. Back to dealership where they cleared a code (first time a code was present) and re-flashed the E-brake control. 4) 12/1/19 incident while sitting at red light on a downward incline. Once I released the brake to move, the car didn't move forward so I looked down at the dash to see the parking brake light on for a quick flash then it went off and the car started to move. Car is back at the dealership.

- Louisville, OH, USA

The brake issue raised its ugly head again. The vehicle has operated fine since the original incident even with the front-end damage. Yesterday, one week after the original incident it occurred again. Cold start leaving a restaurant turned out of parking lot on to side street. Traffic was stopped at a light and I pulled into the left turn lane. Going very slow, haven't even traveled 200 feet. Put pressure on brake pedal to stop and no response, the car keeps rolling forward as I applied extreme brake pressure. At that point I hit the emergency parking brake button and the car stopped just as I hit the rear end of the car in front of me. Thankfully there was no damage to his car. I restarted the car and we pulled off the road into a parking lot to exchange information. Everything operated fine. Left the scene and headed home. When the light changed, I turned left from the side street into traffic. Heavy traffic, slow go. About 1 mile later the traffic slowed down to stop. Once again, the brakes were not responding. I was able to hit the emergency brake and ditch to the side of the road. After traffic passed, I restarted and moved about thirty feet into the safety of a parking lot. At that point I called aaa and had the car towed home. I will have it towed into the dealer this morning.

- Roswell, GA, USA

Cold start, ac unit on, engine at high idle speed. Put car in reverse to back out of the garage. Stepped on the brake pedal and the car kept rolling. Pumped the brake peddle and applied extreme pressure, car did not slow down. Panicked that I would hit a wall, I dropped the car from reverse to drive. Still on high idle, the car would not stop even with extreme pressure applied to the brake pedal. Car continued forward and hit a cabinet in my garage causing considerable front-end damage. Every thing happened so quickly, I couldn't understand what happened at the time. The only thing I could think of was that I must have done something wrong. Restarted the car and all functions were fine. The damage did not affect the operation of the vehicle. I drove to the dealer and I'm waiting for an estimate to repair the damage.

- Roswell, GA, USA

While driving the car the electronic parking brake turned on (without the driver commanding it), stopping the rear wheels from rotating freely, making it very difficult to drive the car. The car was in motion when this happened. This has happened 3 times, on the second time the dealer was able to see the problem and performed a "calibration" but the problem happened again about 1 month later (last night 7/23/19) and left the car stuck in the middle of an intersection, requiring a tow truck to move the vehicle - we took the car to the dealer. The car is currently at the dealer awaiting a diagnosis. I have also contacted GM reporting the problem but they are saying without seeing the problem they won't be able to do anything. This is a relatively new car, 2018, bought in March 2018 and has 24500 miles. Pressing the parking brake release button did not release the parking brake when the problem happened, nor did the automatic brake release process work. There was an error message on the dashboard reporting "service parking brake"

- San Jose, CA, USA

There are two issues: While backing up the car, especially down a hill, the brakes do not work/engage temporarily. Eventually the brakes engage, but you travel further than you intend. The "service brake system" light appears also. This is an intermittent problem. The second braking issue is that the emergency brake will engage without the button being pressed. It just happens and it the emergency brake is difficult to turn off, the car may nee to be turned off on back on to fix. The "service emergency brakes" light appears. This has happened while backing up and in forward in normal driving conditions.

- Short Hills, NJ, USA

I was stopped at an intersection at a traffic light & when the light turned green, I turned left & I'm uncertain if my emergency brakes kicked on or if my car simply stalled out, but my car suddenly would not move. My purse, in the passenger seat flew forward & hit the floor of the vehicle. The car behind me at the light nearly rear ended me, but fortunately did not. We brought the vehicle to jim ellis Buick to be serviced, but they said it appeared fine & was confused. I definitely was not in any danger of hitting anything when turning at the intersection. This incident has made me uneasy when operating my car.

- Peachtree Corners, GA, USA

I was driving the car and when I depressed the brakes the brakes did not engage. The dashboard illuminated with a "brake assist: Alert and I could feel the ABS brakes engage. Luckily this happened while I was pulling into a parking lot. Only had 1,200 miles. Had vehicle towed to dealer. Check engine light did come on and showed code P0557. They replaced the crank shaft position sensor wiring harness and 2 gaskets, based on a repair bulletin and then before I could get the vehicle home it happened again. No brakes, but brake assist activated and ABS was able to stop the vehicle. Check engine light came on again and showed codes P0557, U0401, U0121, & U0078. Had vehicle towed to dealer again. This time they replaced part # 84341899. Luckily both instances happened at low speeds and I was able to safety maneuver the vehicle to a place where I could get towed and nobody was in front of me.

- Fairfax, VA, USA

On only the third day after purchasing a Buick Enclave avenir 2018 I had a safety issue involving the brakes. When applying the brakes a grinding noise with an inability to properly brake and a red service brake assist message appeared on my dash. This has happened from a cold start as well as after being in motion at least 20 minutes city driving. My car has since been in the dealer on 4 occasions replaced three parts and is still currently at the dealers. The dealer has had my vehicle longer than I have almost 40 days now with no information on when I will have it back and I have onlly owned my vehicle for two months.

- Miami, FL, USA