Recovery

When motor (D) is activated, the reduction unit is set in rotation. This consists of a worm screw (E) and helical gear (F).

The helical gear contains a worm screw which microswitch case (G) moves along in both directions so that the case can move in and out according to wheel rotation direction.

At the end of its travel, plunger (H) acting on throttle valve linkage can bring about a maximum opening of about 18°.

If a fault has been established, the idle control motor can be obtained as an individual part.

Recovery

In the case of an error on the idle contact (short circuit or circuit open) the ECU implements one of two strategies according to time of recognition:

• recognition (circuit open) when key is positioned on MAR, no recovery value obtained (ignored);
• recognition (short circuit or circuit open) with key set to MAR, the ECU drives the d.c. motor to a safety position (throttle in idling position).

In the case of an error on the motor (locked or defective, drive stage broken or defective), revealed by a comparison between drive value and actual position under actual idling contact conditions, the ECU activates an rpm limitation, which ranges from 1400 to 2000 rpm.