This vehicle uses an electronic sensor at the accelerator pedal, called the accelerator pedal position sensor, to send information to the computer about the accelerator pedal position. The computer then uses this information to determine how much to open the throttle. If the pedal position sensor fails; the engine will not respond to changes in pedal position. This part costs over $300, so it would be important to check for problems in the wiring and electrical connectors before buying a new one.
This part may be covered under the new vehicle warranty or the Federal emission control warranty; so it would be worthwhile to check with a reliable source such as the Totota Regional Customer Service office about whether they will warranty it.