821-4. Hybrid system
PRIUS_OM_OM47F32E_(EE) 
■ After the 12-volt battery has discharged or when the terminal has been 
removed and installed during exchange, etc. 
The gasoline engine may not stop even if the vehicle is being driven by the 
hybrid battery (traction battery). If this continues for a few days, contact any 
authorized Toyota retailer or Toyota authorized repairer, or any reliable 
repairer. 
■ Sounds and vibrations specific to a hybrid vehicle 
There may be no engine sound or vibration even though the vehicle is able to 
move with the “READY” indicator is illuminated. For safety, apply the parking 
brake and make sure to shift the shift position to P when parked. 
The following sounds or vibrations may occur when the hybrid system is 
operating and are not a malfunction: 
● Motor sounds may be heard from the engine compartment. 
● Sounds may be heard from the hybrid battery (traction battery) under the 
rear seats when the hybrid  system starts or stops. 
● Relay operating sounds such as a snap or soft clank will be emitted from the 
hybrid battery (traction battery), under the rear seats, when the hybrid sys-
tem is started or stopped. 
● Sounds from the hybrid system may be heard when the back door is open. 
● Sounds may be heard from the transmission when the gasoline engine 
starts or stops, when driving at low speeds, or during idling. 
● Engine sounds may be heard when accelerating sharply. 
● Sounds may be heard due to regenerative braking when the brake pedal is 
depressed or as the accelerator pedal is released. 
● Vibration may be felt when the gasoline engine starts or stops. 
● Cooling fan sounds may be heard from the air intake vent. (P. 85) 
■ Vehicle proximity notification system 
In the following cases, the vehicle proximity notification system may be diffi- 
cult for surrounding people to hear. 
● In very noisy areas 
● In the wind or the rain 
Also, as the vehicle proximity notification system is installed on the front of 
the vehicle, it may be more difficult to hear from the rear of the vehicle com- 
pared to the front. 
■ When “Proximity Notification System Malfunction Visit Your Dealer” is 
displayed on the multi-information display 
The vehicle proximity notification system may be malfunctioning. Have the 
vehicle inspected by any authorized Toyota retailer or Toyota authorized 
repairer, or any reliable repairer.