GM Hard Brake Pedal Investigation Expands to 1.1 Million Vehicles
A federal investigation into potentially dangerous braking problems in General Motors vehicles has expanded dramatically, with more than 1.1 million GM, Honda, and Acura vehicles now under investigation for problems involving hard brake pedals, loss of brake assist, and brake system warning messages.
The National Highway Traffic Safety Administration (NHTSA) originally opened an investigation involving the 2023 Cadillac LYRIQ after receiving reports that drivers experienced a hard brake pedal and loss of brake boost. The investigation has now been upgraded and expanded to an estimated 1,164,820 vehicles equipped with GM's electronic brake booster, commonly referred to as the eBoost system.
For California owners, repeated braking problems can be particularly concerning. A vehicle that suddenly requires substantially more pedal effort to stop, displays a "Brake System Failure" warning, or repeatedly requires dealership repairs for its braking system may present both a serious safety concern and a potential warranty issue.
The Problem: GM eBoost Brake System Failures
The investigation focuses on GM's eBoost braking system.
Unlike a traditional power brake system that relies primarily on engine vacuum, the eBoost system electronically provides brake assist. Federal investigators are examining reports that an internal component in the system can fail, potentially causing drivers to experience a suddenly hard brake pedal and reduced brake assist.
According to information obtained during the investigation, GM has investigated failures involving an internal eBoost spindle that can fracture. When the spindle fractures, the vehicle can lose power brake assist. The failure may also affect other important vehicle safety systems.
The original investigation involved Cadillac LYRIQ vehicles, but investigators subsequently determined that the same or similar eBoost braking system was installed in numerous additional vehicles.
The expanded investigation now includes approximately 1.16 million vehicles.
Allegations: Hard Brake Pedals and Brake System Failure Warnings
Vehicle owners have reported experiencing unusually hard brake pedals and warning messages indicating a problem with the braking system.
These failures are particularly concerning because the brake pedal may become significantly more difficult to depress. Although the vehicle may still retain some mechanical braking capability, losing power brake assistance can substantially increase the amount of force a driver must apply to the pedal.
In an emergency braking situation, that difference can become critical.
Drivers have also reported seeing a "Brake System Failure" message either when starting the vehicle or while already driving.
Federal investigators say a fractured eBoost spindle can result in a loss of brake assist. When the problem occurs, the vehicle may also lose certain functions associated with the anti-lock braking system, stability control, and traction control.
The vehicle may sound an audible warning chime, illuminate multiple warning lights, display a "Service Brake System" message, and limit vehicle speed to approximately 43 mph.
Those symptoms make this more than simply an inconvenient dashboard warning. A loss of power brake assist directly affects one of the vehicle's most important safety systems.
Which GM, Honda, and Acura Vehicles Are Under Investigation?
The expanded NHTSA investigation reportedly includes the following vehicles:
2023–2026 Cadillac LYRIQ
2023–2026 Chevrolet Colorado
2023–2026 GMC Canyon
2024–2026 Buick Enclave
2024–2026 Buick Envision
2024–2026 Chevrolet Blazer EV
2024–2026 Chevrolet Equinox EV
2024–2026 Chevrolet Traverse
2024–2026 Chevrolet Cruise Origin
2024–2026 GMC Acadia
2025–2026 Cadillac CELESTIQ
2025–2026 Cadillac OPTIQ
The investigation also includes the 2024–2026 Honda Prologue and 2024–2026 Acura ZDX because those vehicles were manufactured by GM and use the same eBoost braking technology.
An investigation does not mean that every vehicle within those model years is defective. It also does not mean NHTSA has already ordered a recall.
Instead, investigators are attempting to determine the scope, frequency, cause, and safety consequences of the alleged failures.
Recall and Technical Service Bulletin Information
The current investigation traces back to problems initially identified in the Cadillac LYRIQ.
GM previously acknowledged that an internal spindle within the LYRIQ's electronic brake control system could fracture during activation of the anti-lock braking system. A fracture could cause loss of brake assist, reduced ABS functionality, and vehicle speed limitations.
GM modified assembly procedures and developed an over-the-air software update designed to cycle the brake booster during vehicle startup in a manner similar to an ABS event. The procedure was intended to identify a fractured component and alert the driver.
However, one of the reasons NHTSA originally began investigating the LYRIQ was that the software update had not been conducted as a formal federal safety recall.
The current expanded investigation will allow regulators to evaluate whether the problem exists across additional vehicles using the eBoost system and whether further corrective action, including a safety recall, may be necessary.
This is not GM's first encounter with federal scrutiny involving hard brake pedals. NHTSA previously investigated millions of older GM trucks and SUVs for failures of an engine-driven vacuum pump that could cause a hard brake pedal and increased stopping distance. That earlier investigation eventually resulted in a federal recall.
The current investigation involves a different braking architecture, but the underlying safety concern is similar: a driver expects normal power-assisted braking and can suddenly be confronted with a brake pedal requiring substantially more effort.
Symptoms GM Owners Should Watch For
Owners of affected GM, Honda, and Acura vehicles should pay particular attention to changes in how the brake pedal feels.
A brake pedal that suddenly becomes unusually stiff or difficult to depress should not be ignored.
Likewise, drivers should take seriously any "Brake System Failure," "Service Brake System," ABS, stability control, or traction control warnings.
Other potentially relevant symptoms include increased stopping distance, reduced brake assist, multiple warning lights appearing simultaneously, an audible warning chime, or the vehicle suddenly limiting its maximum speed.
The most important evidence for a warranty claim is often the repair history.
If your vehicle experiences one of these problems, make sure the dealership documents your complaint accurately on the repair order. A repair order simply stating "check brakes" may not adequately describe what happened.
The repair order should ideally reflect symptoms such as the brake pedal becoming extremely hard, loss of braking assistance, the warning messages displayed, reduced vehicle speed, or any difficulty stopping the vehicle.
How to Proceed If Your GM Vehicle Has Brake Problems
If you own one of the vehicles under investigation and have experienced braking problems, consider taking the following steps:
Schedule a dealership inspection immediately. Brake-assist problems are safety-related and should not be ignored.
Describe the exact symptoms. Tell the service adviser if the brake pedal became hard, braking assistance disappeared, warning lights illuminated, the vehicle displayed "Brake System Failure" or "Service Brake System," or the vehicle entered a reduced-speed mode.
Keep every repair order. Obtain a copy each time the vehicle is presented for diagnosis or repair, even when the dealer claims it cannot duplicate the problem.
Review your repair orders for accuracy. Make sure the paperwork accurately reflects the complaint you reported.
Document warning messages. If it can be done safely, photographs or video of dashboard warnings may help establish an intermittent problem that disappears before the vehicle reaches the dealership.
Check whether the vehicle has received software updates or brake system repairs. Ask the dealership what repairs, updates, campaigns, or technical guidance apply to your VIN.
Do not assume that "no problem found" ends the issue. Intermittent safety defects can be difficult for a dealership to reproduce. Repeated visits for the same braking complaint may still be significant.
Speak with a California lemon law attorney if the problem continues. Multiple unsuccessful warranty repair attempts, extended periods out of service, or serious recurring safety defects may give rise to rights under California's lemon law.
California Lemon Law and Repeated Brake Problems
California's lemon law may provide protections when a manufacturer cannot repair a vehicle to conform to its warranty after a reasonable number of opportunities.
There is no universal number of repair attempts that automatically makes every vehicle a lemon. The analysis depends on the particular circumstances, including the nature of the defect, the number of repair attempts, the amount of time the vehicle has been unavailable for use, and the applicable warranty history.
Braking problems receive particular attention because they can directly affect vehicle safety.
A consumer experiencing repeated hard brake pedals, loss of power brake assist, brake system failure warnings, or repeated unsuccessful brake repairs should preserve all dealership documentation.
Even if NHTSA's investigation has not yet resulted in a recall, a consumer does not necessarily need to wait for one before evaluating potential warranty or lemon law rights.
Contact Valero Law
If your Cadillac, Chevrolet, GMC, Buick, Honda, or Acura has experienced a hard brake pedal, loss of brake assist, "Brake System Failure" warnings, repeated brake repairs, or another recurring warranty problem, Contact Valero Law.
Valero Law represents California consumers with defective vehicles and can review your repair history to determine whether you may have a claim under California's lemon law.