If the hybrid system will not start Reasons for the hybrid system not starting vary depending on the situation. Check the following and perform the appropriate procedure: The hybrid system will not start even though the correct starting procedure is being followed (Power (ignition) switch (vehicles without smart key system) - Starting the hybrid system, Power (ignition) switch (vehicles with smart key system) - Starting the hybrid system) One of the following may be the cause of the problem: The electronic key may not be functioning properly. (If the electronic key does not operate properly (vehicles with smart key system)) There may not be sufficient fuel in the vehicle’s tank.Refuel the vehicle. (Opening the fuel tank cap) There may be a malfunction in the immobilizer system. (Immobilizer system) The hybrid system may be malfunctioning due to an electrical problem such as electronic key battery depletion or a blown fuse. However, depending on the type of malfunction, an interim measure is available to start the hybrid system. (Starting the hybrid system in an emergency) There is a possibility that the temperature of the hybrid battery (traction battery) is extremely low (approximately below -22°F [-30°C]). (Starting the hybrid system in an extremely cold environment, Power (ignition) switch (vehicles without smart key system) - When the ambient temperature is low, such as during winter driving conditions, Power (ignition) switch (vehicles with smart key system) - When the ambient temperature is low, such as during winter driving conditions) The interior lights and headlights are dim, or the horn does not sound or sounds at a low volume One of the following may be the cause of the problem: The 12-volt battery may be discharged. (If the 12-volt battery is discharged) The 12-volt battery terminal connections may be loose or corroded. (Exterior) The interior lights and headlights do not turn on, or the horn does not sound One of the following may be the cause of the problem: The 12-volt battery may be discharged. (If the 12-volt battery is discharged) One or both of the 12-volt battery terminals may be disconnected. (Exterior) Contact your Toyota dealer if the problem cannot be repaired, or if repair procedures are unknown. Starting the hybrid system in an emergency When the hybrid system does not start, the following steps can be used as an interim measure to start the hybrid system if the power switch is functioning normally. Do not use this starting procedure except in cases of emergency. Pull the parking brake switch to check that the parking brake is set. (Operating instructions) Parking brake indicator will come on. Shift the shift lever to P. Turn the power switch to ACC. Press and hold the power switch for about 15 seconds while depressing the brake pedal firmly. Even if the hybrid system can be started using the above steps, the system may be malfunctioning. Have the vehicle inspected by your Toyota dealer.