2025 GMC Acadia

I purchased this 2025 GMC Acadia on 3/29/2025. About a week into owning it, the navigation stopped working. OnStar was able to reset my system. Then, about a month later, the vehicle locked my keys in the cabin without my knowledge. OnStar was able to unlock my vehicle remotely. Then, on 10/23/2025, I noticed my navigation was not showing my true location. I tried the Google Assistant, and it wasn't connected. After further investigation, my wifi hotspot was not working either, along with other connectivity apps. I researched how to manually reset my system and followed all prompts; that did not fix the problem. I pressed the OnStar button, and nothing happened; no connection. I thought that maybe the vehicle needed to cycle a few times. I let this continue for about a week before calling OnStar from my phone. They told me to press my SOS button; if it didn't connect, then I would need to take the vehicle to the dealership. So I took it to the dealership 11/6/25. They tried to download the update to my vehicle multiple times, over 6 hours at the shop, and the vehicle wouldn't accept the update. It is determined that the OnStar telematics control module is defective. The dealership says the part is backordered, and they do not have an ETA for arrival. After perusing the GM/OnStar forums, I am seeing that this is a repeated issue for many customers on vehicles as old as 2018, and the part doesn't come for 6 months or more in most cases. It does seem more prevalent with vehicles 2022-current. The issue here is that OnStar is touted as a safety feature, and I have been given 3 years of free OnStar service. I am unable to utilize the service (roadside assistance, accident assistance, and navigation) and many other features because of this. GM is aware that this is an issue, and the module is backordered when it should be readily available, since these issues seem to be commonplace. My brand new vehicle should work without issue and should be repaired promptly.

Brakes have failed now three separate times. The brake pedal becomes firm and the car will not stop or slow at all. I am pregnant and also had my toddler in the car with me. No warning symbols on the dash. Taken to dealership after several weeks of communication saying this was a safety issue and received a loaner vehicle. However, they have said if THEY cannot reproduce the issue, we will just get our car back. This is unacceptable. This is one of five issues we have already had with this vehicle.

I have the little feature that will brake for me if it thinks ima get in a wreck. However it’s glitchy!! I can be the only vehicle on road in BOTH directions, cruise set at 60 when out of nowhere the car slams on the breaks. We go down to like 52 then like nothing ever happened we are back to 60. This has happened several times. I have brought the car into my dealership tomorrow have the software updated and the camera recalibrated. Even after these steps were made this issue is still occurring. Happens about one to two times a week, so pretty often. My worries that I will be rear ended one day if this is not corrected.

We had complete brake system failure while driving the car on the highway. The brakes went all the way to the floor when applied and we came inches going into fast moving oncoming traffic before the vehicle stopped. I had to push the break with both feet with all the strength I had to get the brakes to respond at all. The brake assist failure warning light came on and another warning light came on that said SERVICE ESC. I have this on video. This was the first time the warning lights have ever come on. It’s a brand new 2025 car with only 800 miles on it. We were advised by the dealership who sold us the car to get OnStar to tow the vehicle to our local GMC dealership where we bought the car. When the car was hooked up to the diagnoses machine it said brake system failure. I have not received any invoices or paperwork to send you at this point. All I can upload is a video of the warning lights that were appearing on the dashboard after the incident.

Bought new 2025 GMC Acadia in March of same year. At ~4500 miles I started getting Brake Assist, Forward Collision and Electronic Stability Control warning messages on dash. Upon researching, this is an increasingly common issue with this vehicle that can render the brakes unusable. I no longer feel safe in the vehicle and want it refunded. Car is now in the shop. Taken in on 9/11. Problem has been confirmed by dealer.

While driving my 2025 GMC Acadia Denali on [XXX], from Omaha, NE, to Laurie, MO, I received a "Service Brake Assist" warning lamp as well as "Check Engine" and "ABS" warning lamps in St. Joseph, MO. At this point, my vehicle had 6,945 miles on it. We turned around and went back to Omaha. We dropped the car with Gregg Young Chevrolet at 7,095 miles. The dealership identified the issue as EBCM and master cylinder assembly failure. It replaced the EBCM and master cylinder assembly, test drove the car 7 miles and told me my Acadia was ready to go. I did not make it out of the dealership parking lot before the "Service Brake Assist" and "Check Engine" lights came on again. The dealership again identified master cylinder assembly failure, again replaced said assembly, test drove it 10 miles this time and told me my Acadia was ready to go. I got my Acadia and made it 1.1 miles before the "Service Brake Assist" light again came on. I promptly returned my Acadia to the dealership, where it sits today. At the date I am typing this (9/14/25), the dealership has had my Acadia since 8/22/25. The master cylinder has now failed 3 times at this point. First, after 6,945 miles, second after 7 miles, third after 11 miles. The safety of myself and my family was put at risk by the potential failure of my brake system. This should not happen on a brand new car with less than 7K miles and darn sure not 3 times in a row! Yes, the problem has been confirmed by the dealer 3 times. The dealership is now reaching out to GM to determine what to do. I don't have personal knowledge as far as inspection of the component by the manufacturer. It is my understanding from reading about the issue, that both GM and the NHTSA are well aware of this issue and are investigating. I am also aware of pending class-action lawsuits regarding the brake assembly failure. The first time I received the warning lights is when the system failed (or was starting to fail). INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 5

I purchased the car on [XXX]. Drove the car about 8000 miles and then all of a sudden the dash lights all lit up for the brakes, ABS, traction control. I pulled the car over and turned it off. When I restarted my car, the lights continued to stay on and it told me to service immediately. I called my dealer and they could not get me in within 2 weeks so I took it to another local GMC dealer who could get it in to look at it that week. I took it in on July 9th, and then received a called a couple days later telling me that it had a bad Brake control module that they needed to order. A week later was told the part was on backorder. Two weeks later was told the part came in but it was still missing the brake master cylinder and reservoir. At that time, I was told the ETA was unknown and I have been calling back every week. On August 23rd I filed a complaint with GMC and have struggled to get anywhere with them. They tell me the dealer has the parts and the dealer tells me that they do not. I still have no ETA and it has been officially 2 months without a car. I am told that it is not safe to drive. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Brake assist warning message and BRAKE light appeared a couple of weeks ago, along with others. Brought the car into the dealer, who initially thought they cleared the errors and reported no additional issues when they ran the diagnostics. Nothing was cleared. Vehicle application and monitor also does not show an issue, even though the warning appears at each start up and none of the related safety systems work (ABS, ESC, AEB, etc.) that rely on the brake pump. Information from the dealer and owners manual are in conflict, with the dealer allowing me to drive while the owner's manual indicates it should not be driven with the BRAKE light lit. They have now "diagnosed" a "failed" master cylinder unit that includes electronics and the pump. The car had about 4500 miles on it when the issue occurred. I am at a loss for if it should be driven and trusted or not.