560SL (107.048) V8-5.6L (117.967) (1989)
Idle Speed/Throttle Actuator - Electronic: Description and Operation
Idle Speed Control
Fig. 41 Idle Control Unit
The idle speed control unit receives information concerning engine speed, coolant temperature, throttle valve position, air flow sensor position,
automatic transmission selector position, A/C compressor operation, altitude, cruise-control operation, and vehicle speed. Based on information from
these inputs, the idle control unit calculates the appropriate voltage signal needed to maintain the correct idle speed. Idle speeds range from 1200 RPM
(cold), to nominal engine idle speed of 720 to 900 RPM (warm) depending upon inputs to the idle control unit.