Sidekick 2WD L4-1590cc 1.6L SOHC 0 TBI 8V (1992)
OPERATION
ISC solenoid valve opens the bypass air passage when it is turned ON by ECM and closes it when turned OFF.
ECM detects the engine condition by using signals from various sensors and switches and while repeating ON and OFF cycle of ISC solenoid
valve at a certain rate (12.5 times a second), It controls bypass air flow by increasing and decreasing its ON time within a cycle.
While the engine is cranking, ECM keeps ISC solenoid valve ON (maximum ON time rate within one cycle) so as to obtain better start of the
engine.
When the accelerator pedal is depressed while the engine is running (the idle switch is OFF and the throttle valve is at other than idle position),
ECM sets the ON time of the ISC solenoid valve (rate of ON time within one cycle) so that it is determined by the engine conditions and keeps it.
When decelerating, on the other hand, ECM reduces the valve ON time gradually (i.e., the bypass air flow is reduced gradually) to obtain dash-pot
effect.
When the vehicle is at a stop, the throttle valve is at the idle position and the engine is running, ECM controls the bypass air flow by increasing or
decreasing ON time of SC solenoid valve so that the engine speed is kept at a specified idle speed.
With an A/C equipped vehicle, when the A/C is ON, a certain amount of the bypass air is supplied by the A/C VSV independently of this system.
The bypass air supplied by this system is used for fine control to keep the idle speed as specified.
