Engine General Information and Diagnosis: 1A-9
Air Intake System Description
S7RS0B1101006
The main components of the air intake system are air cleaner (1), air cleaner outlet hose (2), electric throttle body (3)
(for the details, refer to “Description of Electric Throttle Body System”.), and intake manifold (4).
The air (by the amount corresponding to throttle valve (5) opening and engine speed) is filtered by the air cleaner,
distributed by the intake, and finally drawn into each combustion chamber. Electric throttle body is not equipped with
IAC valve for idle speed control. Idle speed control is done by the throttle actuator (6) which opens/closes the throttle
valve. (For the details, refer to “Description of Electric Throttle Body System”).
Description of Electric Throttle Body System
S7RS0B1101007
The Electric Throttle Body System consists of electric throttle body assembly, APP sensor assembly, ECM and throttle
actuator control relay.
Among them, assembly components are as follows.
• Electric throttle body assembly: throttle valve, throttle actuator, 2 throttle position sensors
• APP sensor assembly: Accelerator pedal, 2 accelerator position sensors
Operation Description
ECM (5) detects opening (depressed extent of pedal) of the accelerator pedal based on signal voltage of the APP
sensor (1) and using that data and engine operation condition, it calculates the optimum throttle valve opening. On the
other hand, it detects the throttle valve opening based on the signal voltage of the throttle position sensor (3) included
in the throttle body (2) and compares it with above calculated optimum throttle valve opening. When there is a
difference between them, ECM controls the duty ratio (100% – 0%) according to this difference to drive the throttle
actuator (motor) (4) included in the throttle body. When there is no difference, ECM controls the duty ratio to about
15% to maintain the throttle valve opening. In this way, the throttle valve (17) is opened and closed to achieve the
optimum throttle valve opening.
In this system, as the throttle position sensor and APP sensor have 2 sensors (main and sub) each, highly accurate
and highly reliable control and abnormality detection are assured. Also, when ECM detects an abnormality in the
system, it turns off the throttle actuator control relay (8) to step controlling the throttle actuator.
When the throttle actuator control relay is turned off, the throttle valve is fixed at the specified opening below from its
completely closed position (default opening) by the force of the return spring and open spring included in the throttle
body.
This throttle body is not equipped with IAC valve for idle speed control. Idle speed control is done by the throttle
actuator which opens/closes the throttle valve.
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I5RW0A110006-02
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