Idle Speed Control System

Under closed loop conditions, idle speed is controlled by the (ECU). The ECU varies the idle speed control system RPM signal according to gear position, coolant temperature and input voltage signals from other various sensors. The ECU provides an electrical signal to the vacuum control module which in turn converts this electrical signal to a vacuum signal. This vacuum signal operates the idle speed actuator which controls throttle valve position and therefore varies engine idling RPM.

Two idle-up solenoids are also incorporated within this system to increase idle. One is used when the air conditioning is turned on and the other is used for electrical loads and power steering. Fast idle speed for the air conditioner is adjustable by turning the adjusting screw located above the idle-up solenoids.