DTC P0221: Throttle Position Sensor Circuit Range Performance Problem: Description
WARNING: This page is about a different car, the 2003 Infiniti G35. 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 (TP) sensor, etc. The TP sensor responds to the throttle valve movement. The TP sensor has the 2 sensors. These sensors are a type of potentiometer which transforms the throttle valve position into output voltage, and emits the voltage signal to the ECM. In addition, these sensors detect the opening and closing speed of the throttle valve and feed the voltage signals to the ECM. The ECM judges the current opening angle of the throttle valve from these signals and the ECM controls the throttle control motor to make the throttle valve opening angle correct in response to driving condition.