GM eBoost Brake Investigation Expands to 1.16M Vehicles

The National Highway Traffic Safety Administration has opened an Engineering Analysis into failures of General Motors’ eBoost brake system covering an estimated 1,164,820 vehicles. The agency’s Office of Defects Investigation recorded 745 total incidents, 22 crashes or fires, and six injuries in its opening resume for investigation EA26006, which escalates a preliminary evaluation first opened in 2024. No fatalities have been reported. The analysis now reaches every GM vehicle sharing the eBoost system, along with Acura and Honda models built by GM under a joint venture.

Highlights

• Estimated population of 1,164,820 vehicles across GM, Acura, and Honda models equipped with the eBoost system
• 745 total incidents logged — 227 reported to ODI and 531 to the manufacturer, with duplicates removed
• 22 crashes or fires, five injury incidents, and six injuries; zero fatality incidents recorded
• Escalated from Preliminary Evaluation PE24011, opened April 11, 2024, on 2023 Cadillac Lyriq complaints

What Prompted the Engineering Analysis?

ODI opened Preliminary Evaluation PE24011 on April 11, 2024, after receiving complaints alleging loss of brake assist in 2023 model year Cadillac Lyriq vehicles. Owners described a hard brake pedal followed by a “Brake System Failure” message at startup or while driving.

GM shared records from several internal investigations tying the condition to alleged spindle fractures inside the eBoost system. The automaker has stated that when a spindle fractures, anti-lock brakes, stability control, and traction control remain functional until the vehicle comes to a complete stop. At that point, ABS, brake assist, stability control, and traction control functions are all lost.

How the System Warns the Driver

By GM’s account, the failure sets one of three Diagnostic Trouble Codes based on failed performance criteria for the Electronic Brake Control Module (EBCM). Those codes activate an audible chime, a visual “Service Brake System” message in the display, and multiple illuminated malfunction indicator lights covering ABS, traction control, and brakes. Vehicle speed is also limited to 43 mph (70 km/h).

Reports That Conflict With GM’s Explanation

Since PE24011 opened, ODI has continued to receive reports of lost brake assist, and some describe symptoms inconsistent with GM’s spindle-failure description. Those reports allege an immediate loss of brake assist rather than a loss occurring after the vehicle has stopped.

That distinction is what drives the escalation. ODI states that sudden loss of brake assist during a braking event could result in extended braking distance, increasing the risk of a crash or injury, and that further analysis is necessary to assess the potential for eBoost failures to produce safety-related outcomes.

Which Vehicles Are Covered?

ODI identified the following vehicles as built with the eBoost system. The Acura and Honda models were manufactured by GM in a joint venture with Honda and are included in the Engineering Analysis as peer vehicles.

What the Analysis Will Assess

ODI is opening the Engineering Analysis to further assess the safety-related consequences of a failed eBoost system. The agency is simultaneously expanding the investigation’s scope to encompass all GM vehicles that share the system, a substantially wider population than the single model that triggered the original preliminary evaluation. Kevin Mcgough is listed as investigator on the filing, with Sharon Yukevich as reviewer and Tanya Topka as approver.

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