DTC P2101: Electric Throttle Control Function: Description
WARNING: This page is about a different car, the 2011 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feedback to the ECM. ECM controls the throttle valve opening angle in response to driving condition via the throttle control motor.