Toyota has identified a hybrid propulsion system problem in certain 2010-2014 Prius vehicles and will be asking owners to have the software updated for both the motor/generator control electronic control unit (ECU) and the hybrid control ECU. The NHTSA Campaign Number is14V-053.
Due to certain software characteristics used to control the boost converter, transistors within the inverter assembly could experience higher than normal thermal stress during high load driving. The transistors could deform and cause damage to the circuit board, resulting in the illumination of various warning lights on the instrument panel. The vehicle could enter a fail safe mode, reducing power and limiting the distance the vehicle can travel. In some instances, the motor/generator engine control unit (ECU) could reset causing the system to shut down completely, increasing the risk of an accident.
Toyota will be notifying approximately 700,000 owners and dealers will update the software free of charge. If an owner experiences a failure of the inverter before the vehicle receives updated software, the dealer will replace the inverter assembly with a new one. Owners wanting more information about the problem can contact Toyota at 1-800-331-4331. No other Toyota or Lexus vehicles use the same inverter assembly and software used to control the boost converter in the motor/generator control electronic control unit (ECU).
