240 L4-2127cc 2.1L SOHC Turbo B21FT FI (1982)
Idle Control Valve: Description and Operation
CONSTANT IDLE SPEED SYSTEM (CIS)
Constant Idle Speed System
The constant idle speed system incorporates the following main components: electronic control module (ECM) which operates in conjunction with
the Oxygen Sensor Feedback System, air control valve (ACV), throttle switch (TS) and coolant temperature sensor (CTS), Fig. 21.
Fig.22 - Electronic Control Module
Electronic Control Module
The electrical output from the oxygen sensor is transmitted into the ECM, Fig. 22. The ECM supplies a control current to the frequency valve. The
control current incorporates a predetermined frequency and operates by varying the duty cycle. When the oxygen sensor is cold or defective, a
fixed control is switched in after approximately 5-10 seconds. The electronic control module is located inside the vehicle at the right hand side in
front of the right door.
Air Control Valve
The air control valve bypasses air around the throttle valve. A small electric motor rotates clockwise or counterclockwise, depending on the signal
from the electronic control module signal.
Throttle Switch
The throttle actuates a micro switch which controls a circuit in the electronic control unit, when the throttle reaches idle position.
Micro Switch
