General Motors Brake Failure Class Action for 2025 Chevrolet and GMC Vehicles - California Lemon Law

General Motors Facing Class Action Over Sudden Brake Failure in 2025 Models

General Motors is now the subject of a major class action lawsuit alleging that several of its 2025 Chevrolet, GMC, and Buick vehicles were sold with dangerously defective master brake-cylinder assemblies. According to the complaint, these vehicles can lose braking power suddenly and without warning — sometimes within days of being driven off the lot.

Drivers describe the same terrifying pattern. The dashboard lights up with brake, ABS, traction, and stability-control warnings. The brake pedal either becomes rock-hard or drops straight to the floor. Vehicles lose the ability to stop predictably, and in many cases, owners barely avoid collisions. What makes this even worse is that many vehicles have had to sit at dealerships for weeks or months because the defective brake-cylinder components are on nationwide backorder.

What’s the Problem?

The lawsuit claims GM installed defective master brake-cylinder assemblies in several 2025 models, including the Chevrolet Traverse, GMC Acadia, Buick Enclave, Chevrolet Colorado, and GMC Canyon. The master brake cylinder is a critical component responsible for generating hydraulic pressure in the brake system. When it fails, braking power can be severely reduced or lost entirely.

The complaint asserts that internal seals within the master cylinder fail prematurely, allowing brake fluid to bypass or leak internally. Drivers report abrupt changes in pedal feel, including pedals that go stiff or sink all the way down. These failures often coincide with illuminated dashboard warnings for the brake system, ABS, stability control, and forward-collision alerts. Some vehicles automatically reduce speed as a protective measure, while others lose engine or steering assist in the process.

Many vehicles allegedly fail extremely early in their life cycle — sometimes within the first 500 to 2,000 miles. Owners report brake failure before the first scheduled service visit, before their first car payment, and in some cases, before their license plates even arrive. The complaint emphasizes that this is not a maintenance issue but a systemic defect present at the time of sale.

Allegations

The class action lays out multiple claims against GM.

First, plaintiffs assert that GM knew about the brake-cylinder defect before selling the vehicles. They state that GM had data from pre-production testing, warranty claims, and dealership repair reports showing a high rate of cylinder failures. GM also allegedly monitored parts ordering trends and internal diagnostic information that should have made the defect obvious long before 2025 models reached customers.

Second, the lawsuit claims GM concealed the defect. Owners were not told that their vehicles could experience sudden braking loss. The complaint argues that GM marketed these vehicles as safe, reliable, and suitable for everyday family use, despite knowing that the braking system could fail abruptly.

Third, plaintiffs argue that GM violated its New Vehicle Limited Warranty by not repairing the vehicles within a reasonable time. Many owners report their vehicles sitting at dealerships for eight to twelve weeks, with no firm estimate on part availability. Some dealerships told owners that the vehicles were unsafe to drive, while others sent drivers home because GM had no loaners available.

Finally, the complaint alleges violations of consumer-protection statutes, fraudulent concealment, and unjust enrichment, arguing that GM profited from selling defective vehicles while shifting the burden and risk onto consumers.

Recall / TSB

No recall has been issued for the 2025 vehicles at the center of this lawsuit. Despite hundreds of brake-related complaints filed with NHTSA, GM has not taken the step of initiating a safety recall.

The complaint does reference a prior service update — GM’s Service Update N242482170, issued in December 2024. That update concerned defective master brake-cylinder assemblies in the 2024 Traverse and certain 2025 Enclave models. Importantly, the service update did not extend to the 2025 vehicles now experiencing the same or similar failures. According to the lawsuit, this demonstrates that GM already had knowledge of brake-system problems but did not expand the coverage to include other 2025 models using nearly identical components.

Another key issue is the severe shortage of replacement parts. Even when dealerships diagnose the master-cylinder defect, many cannot complete repairs because GM’s replacement parts are on nationwide backorder. Some owners waited months for parts, while others had replacement components installed only to experience additional or repeated failures.

Symptoms

The complaint documents an extensive pattern of consistent symptoms reported by drivers of the affected vehicles.

The most common sign is a sudden cluster of dashboard alerts. Owners describe the brake warning light, ABS indicator, stability-control light, and forward-collision system warnings all illuminating at once. Many also receive messages such as “Service Brake Assist,” “Service ESC,” “Brake Assist Failure — Press Hard to Brake,” or “Speed Limited.” These warnings can appear when the vehicle starts, when braking lightly, or even while traveling at highway speed.

Pedal behavior changes dramatically during these incidents. Some drivers describe a brake pedal that becomes extremely stiff, requiring both feet to push down to slow the vehicle. Others experience the opposite — a pedal that sinks straight to the floor without providing braking power. In certain cases, the vehicle enters a reduced-power mode or activates emergency systems to try to compensate for the loss of hydraulic pressure.

The experiences described in the lawsuit include near-misses in intersections, sudden loss of braking on busy roads, and vehicles traveling into opposing lanes or traffic when the braking system collapses. Many drivers were transporting children at the time of failure. In several reports, dealerships later confirmed that the brake system was unsafe and told owners not to drive the vehicle again.

What stands out in the complaint is the timing. These failures repeatedly occurred in vehicles that were only days or weeks old, with mileage counts often under 1,500. The early onset and frequency of failures are central to the plaintiffs’ argument that the defect existed at the time of sale and was not disclosed to consumers.

How to Proceed

Drivers experiencing brake-system issues in these 2025 GM models should keep detailed records of everything related to the defect. This includes repair orders, photographs of warning lights, communications with dealerships, and any instances where the vehicle had to be towed. In California, the timeline and number of repair attempts matter. If your vehicle has been in the shop for extended periods, or if the defect recurs even after attempted repairs, the vehicle may qualify as a lemon.

It is also important to pay close attention to symptoms. Any brake-system warning, unusual pedal feel, or sudden loss of braking force should be treated as a serious safety event. Owners should avoid driving the vehicle until a dealership evaluates it. If repeated attempts to fix the defect fail — or if GM cannot supply necessary parts in a reasonable amount of time — legal rights may be triggered under the California Lemon Law.

For many consumers, navigating these issues alone can be difficult, particularly when dealing with long backorders, conflicting dealership guidance, or inconsistent information from GM. A lemon law attorney, like Valero Law, APC, can help determine whether the vehicle qualifies for a full repurchase, a replacement vehicle, or a substantial cash settlement.

Call Valero Law

If your 2025 Chevrolet Traverse, GMC Acadia, Buick Enclave, Colorado, or Canyon is showing brake warnings, experiencing loss of braking power, or has been stuck at a dealership waiting for parts, you may have rights under California’s Lemon Law. These brake-system failures are not minor issues. They directly affect the safety of drivers and passengers, and California law provides strong protections for consumers in exactly this type of situation.

You may be entitled to a repurchase of your vehicle, a replacement, or meaningful cash compensation. Valero Law, APC handles these cases at no upfront cost to you.

If you’re in California and your GM vehicle has brake-system defects, brake-assist failures, or master-cylinder issues, call Valero Law, APC at (424) 299-4447 or request a free Lemon Law case evaluation today.