DTC P1238, P2119: Electric Throttle Control Actuator: Description
WARNING: This page is about a different car, the 2013 Infiniti FX50. 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 throttle position sensor detects the throttle valve position, and sends the voltage signal to the ECM. The ECM judges the current opening angle of the throttle valve from this signal and opens/closes the throttle valve in response to driving conditions via the throttle control motor.