NHTSA Complaint #11704198 — 2023 GMC YUKON

While driving in approximately 10°F weather after the vehicle had been parked outside overnight during snowfall in Chicago, the vehicle displayed a warning that said “Do Not Drive — Maximum Speed 43 MPH.” At the same time, the brake pedal became extremely hard and the vehicle had significantly reduced braking ability, requiring much longer stopping distance. This occurred without any brake warning lights beforehand. After the vehicle warmed up and was restarted, the message eventually cleared but then there was a new transmission warning and the check engine light went on. After driving for a long commute, eventually all warnings disappeared. I personally know another 2023 Yukon owner who experienced the exact same message and braking loss under similarly cold conditions, which suggests this may be a broader safety issue affecting this model year. Because this involved a sudden safety-system activation combined with temporary brake loss, there was a real risk of being unable to stop the vehicle safely or avoid a collision. My vehicle is within the year range of GM’s brake-system software recall N242447990 (eBCM brake fluid loss detection issue), and it is unclear whether my case is related, but the symptoms point to a potential systemic braking or electronic brake control problem in the 2023 Yukon. This issue warrants investigation due to the combination of: • Hard brake pedal • Reduced braking performance • Speed-limiting safety warning • No prior diagnostic warning • Occurrence in very cold temperatures A sudden loss of braking ability is a serious safety defect.