GM Said Its Brake Failures Only Happen After You've Stopped. Drivers Disagree.

GM has a story about its brakes, and it has been telling it to NHTSA since 2024. It goes like this: inside the eBoost electronic brake booster, a spindle can fracture during hard ABS events. When it does, GM says, you lose nothing that matters: ABS, stability control, traction control, all alive. Once the car stops, the system politely powers down its helpers, lights up the dash, and caps you at 43 mph, a failure with manners. There is just one problem with this story: drivers keep reporting that the brake assist vanishes in the middle of braking, while the car is still moving.^[1]

On August 21, NHTSA's Office of Defects Investigation stopped taking GM's word for the sequence of events and opened Engineering Analysis EA26006.^[1] An EA is the last stop on the agency's investigation ladder, the step right before it can demand a recall.^[3] Look at the scope and you see why: the population is now an estimated 1,164,820 vehicles across fourteen nameplates, from the Lyriq that started it through the Colorado and Canyon, the Enclave, Envision, Blazer EV, Equinox EV, Traverse, Acadia, Celestiq, and Optiq. Then come two badges you would not expect, the Honda Prologue and the Acura ZDX, which GM manufactured in a joint venture and which NHTSA lists as peer vehicles.^[1][4] Your Honda has GM brakes now; enjoy that thought at the next stoplight.

This is where the detective work pays off, because ODI put the disagreement in writing: GM's version is that assist survives until the complete stop, while the drivers' version, in ODI's words, describes "symptoms inconsistent with GM's description of a spindle failure," alleging "an immediate loss of brake assist functionality as opposed to the loss occurring after the vehicle comes to a complete stop."^[1] In the dialect of federal regulators, that sentence is a raised eyebrow the size of a billboard. ODI adds that the sudden loss of brake assist during a braking event "could result in extended braking distance, which increases the risk of a crash or injury." Twenty-eight months passed between the original preliminary evaluation in April 2024 and this escalation.^[5] You do not climb NHTSA's ladder on vibes.

Fairness requires the other file, and GM's engineering case has a reassuring spine even if you accept every word of it: the hydraulic circuit does not die with the assist, so the pedal goes heavy but not dead. You get chimes, a "Service Brake System" message, a dashboard lit up like a slot machine, and a car that refuses to exceed 43 mph.^[1] Zero fatalities in 745 incidents is a fact worth more than a paragraph of my prose. Still, an EA is an investigation, not a verdict, and NHTSA opens these and sometimes closes them with a shrug. Those mid-braking reports could be post-stop events misremembered by frightened drivers. That is the strongest case for the defense, and it is not nothing.

What you do with this, if you drive one of the fourteen nameplates: memorize the symptoms, because the pedal goes hard without warning while "Brake System Failure" or "Service Brake System" appears on the display. Then come the chimes, the warning lights, and the car suddenly deciding 43 mph is plenty.^[1] If it happens while you are moving, press harder, because the unassisted brakes still work, then get off the road. Check your VIN at nhtsa.gov/recalls, understanding that you will find nothing yet, because an EA is not a recall and there is no remedy to schedule.^[7] And if you live through it, file a complaint at NHTSA's safercar.gov. This investigation exists because drivers wrote in; the preliminary evaluation became an engineering analysis on the weight of 227 of those direct complaints.^[1] That pipeline runs on paperwork, so feed it.

One more thing the paperwork says, for the record: GM already pushed an over-the-air software program to 2023 Lyriqs back in 2024, reaching 81.7 percent completion by that June, and it was not a recall, as the feds' own file confirms.^[9] Software updates that fix safety defects without the word "recall" attached are a genre this site has covered before, and it never gets less interesting.