THROTTLE VALVE CONTROL

Engine-ECU controls the throttle valve position to suit the driving or stopped condition of the vehicle based on the signals that are input by various sensors.
System Configuration Diagram

When engine is running

Engine-ECU actuates the throttle valve control servo to fully open the throttle valve. In a driving range in which the exhaust gas recirculation control is being effected, the throttle valve closes to create a vacuum in the inlet manifold.

When engine is stopped

Engine-ECU actuates the throttle valve control servo to fully close the throttle valve for 3 seconds. This cuts off the flow of intake air and prevents the engine from run on (dieseling).

When a problem develops

If the engine-ECU detects a serious problem, it immediately closes the throttle valve fully to stop the engine.