Idle Control

OPERATION
When the pedal position sensor is not operated, the idle speed of the engine is kept constant to the nominal engine speed by way of controlled opening of the throttle valve. The working range of the idle controller depends upon the coolant temperature which is detected by the Electronic Throttle Control (EML) coolant temperature sensor. The nominal idle speed is influenced by three data variables:

- By the coolant temperature (the nominal idle speed is increased at low temperatures)

- By the setting of the gear selector lever in vehicles equipped with automatic transmission (the nominal idle speed is reduced with gear engaged and at low temperature)

- By the opening status of the air conditioning system (the nominal idle speed is increased by approx. 100 rpm when the A/C compressor is switched on).

When starting the engine, the throttle valve opening is increased dependent on temperature to a start opening position (start is detected at <20 rpm).

The idle control system is active at a speed of < 1600 rpm. Apart from this condition, either the speed must be < nominal speed, the vehicle speed <8 km"h, clutch depressed (manual transmission) or the gear P or N engaged (automatic transmission).

The throttle valve opening is increased depending upon the engine speed in order to reduce the vacuum in the intake pipe during deceleration fuel cutout.