Component description of throttle valve actuator - GF30.20-P-2020KE

ENGINE 271.921 /940 /941 /944 /946 /948 /955 /956

Location

Fig 1: Identifying Throttle Valve Actuator - Engine 271.948

The throttle valve actuator is located at the front left of the engine.

Task

The throttle valve actuator regulates the functions:

Idle speed
Driving mode (according to the accelerator pedal position and engine load)
Cruise control mode
Electronic accelerator emergency mode

Design

Fig 2: Throttle Valve Actuator Design

Function

Fig 3: Identifying Throttle Valve Actuator Circuit Diagram

The actuator motor in the throttle valve actuator adjusts the opening angle of the throttle valve continuously from approx. 0 to 90° according to the presets from the ME control unit (N3/10).

Hereby, both the actual value potentiometers indicate the current position of the throttle valve to the ME control unit.

In de-energized status (e.g. limp-home), the opening angle of the throttle valve (from 10 to 12°) is determined by the spring capsule.

When the throttle valve actuator is connected to the vehicle for the first time, the ME control unit carries out an adaptation of the actuator (learning the lower and upper mechanical end stop of the throttle valve) on its own.