Federal Regulators Are Now Investigating Brake Failures in 1.16 Million GM, Honda, and Acura Vehicles
NHTSA has escalated its investigation into GM's eBoost brake system to a full engineering analysis covering 1.16 million vehicles across 14 model lines, including two Honda and Acura models built through a GM joint venture.
A brake problem that started with a single electric SUV model two years ago has now ballooned into one of the largest active vehicle safety investigations in the US.
The National Highway Traffic Safety Administration escalated its probe into General Motors' electronic brake booster system, known as eBoost, to a formal engineering analysis on August 21 — the agency's highest level of pre-recall investigation. What began in April 2024 as a narrow review of roughly 3,300 Cadillac Lyriq electric SUVs has now expanded to cover an estimated 1,164,820 vehicles across 14 model lines from 2023 through 2026.
The list reads like a cross-section of GM's entire modern lineup: Cadillac Lyriq, Optiq, and Celestiq; Chevrolet Colorado, Blazer EV, Equinox EV, and Traverse; GMC Canyon and Acadia; Buick Enclave and Envision; and even the Cruise Origin. Notably, the investigation also pulls in two vehicles GM builds for other automakers under a joint venture — the Honda Prologue and Acura ZDX, both manufactured at GM's Spring Hill, Tennessee plant.
At the heart of the issue is a component called a spindle, located inside the eBoost brake-assist unit. GM has told investigators that under certain conditions — particularly during hard, anti-lock braking events — that spindle can fracture. According to the automaker, when that happens, anti-lock brakes, stability control, and traction control are all supposed to keep functioning normally right up until the vehicle comes to a complete stop.
Real-world complaints, though, describe something more alarming. Drivers have reported a suddenly hard brake pedal, a "Brake System Failure" warning appearing either at startup or mid-drive, and in some cases what they describe as an outright loss of brake assist while actively trying to slow down — a discrepancy between GM's technical explanation and what owners say they're actually experiencing on the road.
The numbers behind the escalation are serious. NHTSA has logged 745 unique failure reports tied to the eBoost system, including 22 crashes or fires and six injuries. No fatalities have been reported so far.
It's worth being precise about what this investigation is and isn't, though. NHTSA has not issued a recall covering all 1.16 million vehicles, and the agency's filing doesn't instruct owners to stop driving or park their vehicles outside as a precaution. An engineering analysis can eventually lead to a recall, a revised repair, additional testing — or, in some cases, no further action at all if regulators determine the risk doesn't rise to the level of a safety defect. GM, for its part, has stated its own internal investigation found the reported issue doesn't present an unreasonable safety risk, though neither GM nor federal regulators have issued a formal recall tied specifically to eBoost as of now.
This isn't GM's only active federal safety review, either. The automaker is simultaneously facing a separate engineering analysis covering nearly 1 million pickups and SUVs — including the Cadillac Escalade, Chevrolet Silverado 1500, and GMC Yukon — over reported engine failures involving its L87 V8 engine, even after owners had already received an earlier recall repair.
For now, NHTSA's advice to owners of any listed vehicle is straightforward: don't assume a failure is inevitable, but treat any brake warning light, unusually firm pedal, or unexpected braking behavior as something worth an immediate trip to the dealer, rather than waiting to see if a formal recall notice eventually arrives.
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