2020 Volvo XC40 Powertrain & Transmission Problems

On 01/04/2026, while operating a gas-powered 2024 Volvo XC40, the vehicle experienced a catastrophic Sudden Unintended Acceleration (SUA) event while stationary at a red light. With the service brake fully depressed, the internal combustion engine began to surge and rev uncontrollably, making loud noises. The engine torque increased in direct response to increased brake pressure, eventually overcoming the braking system and forcing the vehicle forward into the 3-way intersection. Technical Details: Brake-Throttle Override (BTO) Failure: The vehicle’s safety logic failed to prioritize the brake signal over the uncommanded throttle increase. Shifter Interlock Malfunction: During the surge, the electronic gear selector was unresponsive, preventing shifting into Neutral (N) to disconnect power. Shifting capability only returned once the vehicle was brought to a forced stop. Prior Symptoms: Intermittent "idle flaring" and surging were noted 48 hours prior to the failure. Safety Risk: The vehicle moved into traffic against my intent and physical input, posing a high risk of collision. The car was towed by Volvo Road Assistance on 1/4/26 to the Volvo dealership later that evening. This incident mimics the "Powertrain Control System" defects currently documented in NHTSA Campaign 25V392 and the Becker v. Volvo class action, suggesting the software defect extends to ICE (Internal Combustion Engine) models. The car is currently at the Volvo Dealership for diagnostics. The service intake person has not provided an update on whether they have been able to duplicate the issue. I do not know what diagnostics have been performed on the car at this point. There were no warning signs or messages prior to the failure. Some minor surging had been noticed a couple of days before, but this latest incident was catastrophic and a safety risk. I felt trapped in my car.