Throttle Position Sensor
The throttle position sensor responds to the throttle valve movement. The throttle position sensor has two sensors. These sensors are a kind of potentiometer which transform the throttle valve position into output voltage, and emit the voltage signals to the ECM. The ECM judges the current opening angle of the throttle valve from these signals and controls the throttle valve opening angle properly in response to driving condition via the throttle valve motor.
When one of the accelerator pedal position sensors has a malfunction, ECM uses a signal from another accelerator pedal position sensor. Furthermore, ECM monitors the amount of intake air and corrects throttle position. When both position sensors have a malfunction, ECM stops the throttle valve control. Consequently, the throttle valve angle is fixed at 10% by the spring force, enabling emergency driving.