IACV Control Idle Speed

IACV Control Idle Speed
Conditions in which the ECM operates the IACV control idle speed is as follows:
^ If any automatic transmission gears other than P or N are selected.
^ If air conditioning is switched on.
^ If cooling fans are switched on.
^ Any electrical loads activated by the driver.

Function
The idle air control valve utilises two coils that use opposing pulse width modulated (PWM) signals to control the position of a rotary valve. If one of the circuits that supplies the PWM signal fails, the ECM closes down the remaining signal preventing the idle air control valve from working at its maximum/minimum setting. If this should occur, the idle air control valve assumes a default idle position at which the engine idle speed is raised to 1200 rev/min with no load placed on the engine.