Passat L4-1984cc 2.0L DOHC (9A) (1990)
Idle Stabilizer Valve
IDLE STABILIZATION CONTROL
The idle speed is electronically controlled by the CIS-E Motronic control unit with relation to engine coolant temperature and load signals.
If the control unit recognizes that the idle speed is not within specified ranges, approx. 800-900, the duty cycle for the idle stabilizer valve will be
modified. This adjusts the valve open to allow more or less air to bypass the throttle valve as necessary to maintain the correct idle speed.