Read our full breakdown of the GM master brake cylinder issue
My Investigation Into the 2025 GMC Acadia Problems: Here’s What the Data Shows
Problem analysis of the 2025 GMC Acadia found issues including master brake cylinder failure, electronic brake control malfunctions, and infotainment connectivity problems.
Key Points
- Our team reviewed real consumer complaints, NHTSA data, owner feedback, and internal data to identify commonly reported problems with the 2025 GMC Acadia.
- Owners most often reported master brake cylinder failures, infotainment and connectivity issues, spontaneous sunroof glass breakage, and some transmission or engine problems.
- Owners with repeated or unresolved defects may have rights under state lemon laws, including a refund, replacement, or compensation.
Our firm has been tracking the master brake cylinder issue in GMC and Chevy vehicles since early 2025. That tracking led to a class action investigation and ultimately pending litigation. So when I sat down to research the 2025 GMC Acadia, I already knew what the top issue would be before I even pulled the first complaint.
My name is Sergei Lemberg, and I’m a lemon law attorney with over twenty years of experience representing consumers in vehicle defect cases. I reviewed NHTSA complaints, owner feedback, and our own internal data for the 2025 GMC Acadia.
As always, not all Acadias will experience these issues. These are simply the most commonly reported defects, likely affecting a percentage of vehicles.
Let’s get started.
Most Common Problems
My research found the following as the top issues. In the next section, I will break down each issue.
- Master Brake Cylinder Failure: Reports show sudden brake assist failures, mushy brake pedals, and multiple replacement attempts due to defective master cylinders.
- Infotainment and Connectivity Issues: Owners face intermittent or total loss of OnStar services, GPS inaccuracies, and problems with Apple CarPlay and wireless media playback.
- Spontaneous Sunroof Glass Breakage: Several complaints point to sunroofs shattering unexpectedly causing safety hazards.
- Transmission and Engine Concerns: Incidents of slipping, hard shifting, and engine replacements have been reported, although less frequently than brake-related issues.
2025 GMC Acadia Complaint Summary
| Complaint Category | Number of Complaints |
|---|---|
| Service Brakes | |
| Forward Collision Avoidance: Automatic Emergency Braking | |
| Unknown Or Other | |
| Forward Collision Avoidance: Warnings | |
| Engine | |
| Electrical System | |
| Exterior Lighting | |
| Forward Collision Avoidance: Adaptive Cruise Control | |
| Power Train | |
| Steering |
Top Problem #1: Master Brake Cylinder Failure
As mentioned in the intro, master brake cylinder failure is the top issue we have been tracking on this vehicle, and the complaint data confirms it.
Owners report symptoms including:
- Sudden loss of power brakes or brake assist while driving
- Warning lights such as “Service Brake Assist,” ABS, and ESC illuminating on the dashboard
- Mushy or sinking brake pedal requiring excessive force to stop
- Vehicle becoming unsafe to drive, sometimes resulting in near accidents
- Repeated failures requiring master cylinder replacements, with new parts also failing
One owner described
“Vehicle had a “service ESC” and “service brake assist”. Dealership said the master cylinder is bad and it is not safe to drive. Now its sitting at the dealership with NO eta on parts and no loaner cars.” Another shared, “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.”
Top Problem #2: Infotainment and Connectivity Issues
I also found frequent complaints about the 2025 Acadia’s infotainment system and connectivity features. Here are some common symptoms of this issue:
- OnStar telematics frequently losing connection or completely failing
- GPS inaccurate or offline, resulting in missed directions and nonfunctional garage door openers
- Apple CarPlay interruptions where media playback stops unexpectedly
- SiriusXM and wireless charging features not consistently working
One owner wrote
“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.” Another shared, “OnStar/Telematics Module cuts out, rending GPS and OnStar functions useless”
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Top Problem #3: Spontaneous Sunroof Glass Breakage
While less common, there are multiple reports of the panoramic sunroof glass shattering without warning.
- Sudden loud explosion sound while driving
- Glass shards falling inside the vehicle, causing potential injury
- Safety hazard due to driver distraction and debris risk
- Conflicting information about warranty coverage and repair approval
One driver said
“Approximately 2 months after purchase, the sunroof spontaneously shattered/exploded while driving on the interstate. We had it fixed and about 3 months after that, the same exact thing happened.” The dealer reportedly requested engineering inspection before approving warranty repairs.
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Top Problem #4: Transmission and Engine Problems
Some 2025 Acadia owners experience transmission hesitations, shuddering, and in severe cases, engine replacements under warranty.
- Hard shifts and RPM bounce during gear changes
- Engine surges or stalling without clear diagnostic codes
- Engine and turbo replacements after prolonged repair delays due to part backorders
- Transmission replacements not always resolving shudder issues
One affected owner shared
“Around 7k miles on the vehicle, driving down the road it kept coming to a stop and skipping. Pulled into the parking lot the best that I could and put it into park. After it wouldn’t shift into anything. Never gave any dash signals. It is currently in the shop getting a whole new transmission.” Another noted, “Engine surges and idles rough- dealership could not diagnose.”
What Should You Do If Your 2025 GMC Acadia Is a Lemon?
If your 2025 GMC Acadia shows recurring defects that substantially impair its use, value, or safety, you might have a lemon law claim. A lemon vehicle is typically one with serious issues that remain unresolved after a reasonable number of repair attempts or significant time in the shop.
Here are important steps to take:
- Document all problems, repair visits, and communications with dealerships in detail
- Keep copies of repair orders, invoices, and written statements from service technicians
- File a complaint with the National Highway Traffic Safety Administration (NHTSA) to add to the safety data pool
- Review your state’s lemon law criteria and deadlines carefully—they often have strict time limits
At Lemberg Law, we understand the frustration and risk caused by these defects. We don’t get paid unless you win, and we provide free consultations to help determine if your vehicle qualifies for compensation or repurchase under your state’s lemon law. I encourage you to contact us today before your lemon law claim windows close. Let us fight for your legal rights while you focus on staying safe.
Click 877-795-3666 now to call us.
Or go ahead and fill out our Contact Form. Our services are absolutely free to you.
About the Author:
Sergei Lemberg is an attorney focusing on consumer law, class actions related to automotive issues, and personal injury litigation. With nearly two decades of experience, his areas of practice include Lemon Law (vehicle defects), Debt Collection Harassment, TCPA (illegal robocalls and texts), Fair Credit Reporting Act, Overtime claims, Personal Injury cases, and Class Actions. He has consistently been recognized as the nation's "most active consumer attorney." In 2020, Mr. Lemberg represented Noah Duguid before the United States Supreme Court in the landmark case Duguid v. Facebook. He is also the author of "Defanging Debt Collectors," a guide that empowers consumers to fight back against debt collectors and prevail, as well as "Lemon Law 101: The Laws That Lemon Dealers Don't Want You to Know."
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