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

ENGINE 113.967 in MODEL 219 

ENGINE 113.964 in MODEL 164.1 

ENGINE 113.971 in MODEL 251 

Location 

The throttle valve actuator is flanged to the intake manifold at the rear.

Task 

The throttle valve actuator regulates the functions:

• Idle speed
• Driving mode, corresponding with the accelerator pedal position and load
• Cruise control mode
• Emergency electronic accelerator pedal

Design 

Function 

The actuator motor in the throttle valve actuator continuously adjusts the throttle valve from around 0 to 90° according to the specified value in the ME control unit.

The typical power consumption of the pulse width modulation signal is

approx. 1 A, however it is possible up to approx. 9 A. For output stage protection the power is limited to 6 A after approx.

30 seconds.

The actual value potentiometers advise the current position of the throttle valve to the ME control unit.

The signals of both actual value potentiometer are opposed.

1. Ignition "Off" 

   In deenergized status, the throttle valve position is determined by the spring capsule (8 to 10° opening angle).

2. Ignition "On" 

   When the ignition is switched on, the actuator motor in the throttle valve actuator is operated by the ME control unit.

   The throttle valve adopts a position which depends on the coolant temperature.

3. Idle speed 

   Depending upon the coolant temperature and engine load, the actuator motor changes the rpm in the idle speed range by opening the throttle valve further (increased mixture) or closing it further.

   (less mixture).

   Here, the throttle valve can be closed further by the actuator motor against force of the spring capsule.

4. Driving mode 

   In the driving mode (full / partial load), the actuator motor changes the throttle valve position depending on the different load states and / or according to the input signals from the accelerator pedal sensor dependent on the performance maps.

5. Emergency running 

   If the actuator is deenergized, the throttle valve is set to approx. 8 to 10° opening angle by the spring capsule.

   In the idle speed range, this results in an engine speed of approx. 1200 to 1400/min.

For first time connection of the throttle valve actuator to circuit 30 or 87, the ME control unit carries out automatically within approx. 60 seconds the following actions:

• Determining the emergency running position
• Determining the lower mechanical stop
• matches actual value amplifier (signal 1 and 2) in the ME control unit.
• Inspection of return spring (always performed with ignition ON)

Requirement: Drive position P or N, vehicle is stationary, engine OFF, ignition ON, coolant temperature 5°C up to 100°C and accelerator pedal not operated.

The procedure must be activated using STAR DIAGNOSIS, if the throttle valve actuator or the ME control unit have been replaced, otherwise the engine may surge.