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Idle speed control

Idle speed control


Idling speed is controlled via a single-coil idle air control (IAC) valve on the basis of a PWM voltage from the electronic control module.

Automatic idle speed control is adaptive, i.e. it adapts continuously to changes that take place during the life of the engine. These changes may be wear in the engine, dirt or leaks in the intake manifold or throttle body.

The electronic control module is programmed to maintain idling speed constant at 900±50 rpm when the engine is warmed up at the same time as the throttle position sensor indicates idle speed.

Engine speed compensation takes place when A/C is switched on and when a gear position other than P or N is selected on cars with automatic transmission.