Brake problems in GM EVs draw greater federal scrutiny

General Motors electric vehicles, including ones built in partnership with Honda, are now facing increased scrutiny from the top U.S. auto safety regulator after hundreds of incidents, more than 20 crashes or fires, and at least six injuries.

The brake problems also extend to some non-EV models, including the Chevy Colorado, GMC Canyon, and the Buick Enclave and Envision. More than 1 million vehicles may be affected.

The National Highway Traffic Safety Administration (NHTSA) first started its investigation in April 2024 after reports of trouble from owners of 2023 model year Cadillac Lyriq vehicles. The agency’s Office of Defects Investigation (ODI) said Monday that it was upgrading this probe to what’s known as an “engineering analysis.” That’s the highest level of investigation that ODI performs, and is often a step the office takes before telling a company to issue a recall.

The initial complaints ODI received two years ago typically involved owners describing receiving a “Brake System Failure” message when starting up the vehicle, or after coming to a complete stop. GM performed “several internal investigations” into the issue, according to ODI, and determined that the problem was linked to fractures in the spindle of its “eBoost” brake-by-wire system.

But ODI said on Monday that it kept receiving reports of a loss of braking assistance that were “inconsistent with GM’s description of a spindle failure.” The additional reports described an “immediate loss of brake assist” while a customer was in the process of braking to slow their car down, which the safety regulator said “could result in extended braking distance, which increases the risk of a crash or injury.” ODI said it needs to do a further analysis of the potential for failures in the eBoost system.

The eBoost system was introduced in 2019 and gradually rolled out to more models over the years. The system ditches a traditional mechanical link between the brake pedal and the braking system, opting for an electronic one instead. This allows GM to change the brake “feel” in different driving modes. The automaker put eBoost on its most popular EVs, like the Blazer EV, Equinox EV, Cadillac Lyriq, and the Honda Prologue and Acura ZDX, which it made with Honda in a joint venture. The Cruise Origin — the purpose-built electric autonomous vehicle with no steering wheel or pedals, which GM abandoned in 2024 — also used eBoost.

In one crash reported to NHTSA, the driver of a 2025 Lyriq said they lost their brakes while trying to pull into a parking space in front of the store. The vehicle drove over the curb and crashed through the store front, coming to rest “mid-way in the store, amidst the furniture and store structure,” according to the driver.