Idle control
While the engine is idling, the ECM controls the throttle actuator to maintain the desired idle speed at any engine load.
Overclocking management
When the accelerator pedal is depressed, the ECM opens the throttle depending on the signal from the accelerator pedal position sensor (APP).
Cruise control system
When the cruise control system is operating, the ECM controls the throttle actuator to maintain the set speed. The throttle actuator acts as an actuator for the cruise control system.
Accelerator pedal position sensor (APP)
As the accelerator pedal position changes, the sensor changes the voltage signal sent to the ECM.
Throttle body
The throttle body is single-chamber with a side throttle actuator. The lower area under the throttle is heated by engine coolant from the cylinder head to prevent ice from forming on the throttle.
Idle speed control system
With the engine cold, air conditioning on, transmission in gear, brake pedal depressed, high power steering load, or high generator load, the ECM computer controls the amount of current supplied to the throttle actuator to maintain the desired idle speed.
Brake Pedal Position Sensor
The brake pedal position sensor sends a signal to the ECM when the brake pedal is depressed.
Electrical power steering signal (EPS) (versions with hydraulic booster EPS)
The EPS system sends a signal to the ECM when the load on the power steering is too high.
Diagram of the electronic throttle control system
The electronic throttle control system consists of the throttle position actuator, throttle position A/B sensor (TR), accelerator pedal position sensor (APP), electronic throttle control relay (ETCS) and the ECM.