Electric Throttle Valve Actuator

Many high-performance engines have individual throttle valves. In the S54 engine, these are arranged around a separate throttle body shaft. The individual throttle valves are operated by an electric positioning motor without a direct mechanical link to the accelerator pedal.

Tasks of electric throttle valve (EDK)

The electric throttle valve fulfils following tasks:

- Implementing the driver's load choice

- Vehicle speed control

- Intervention by the vehicle handling control systems

- Emergency operation

- Load application (e.g.: seat heating, air conditioning system, lights)

- Maximum speed limitation

Structure and function of the EDK and potentiometers

The electric throttle valve (EDK) is operated by DC motor via a gearing system. The adjustment positions are sensed by means of potentiometers. The first potentiometer is a discreet component, whereas the second potentiometer is connected to the ”electric throttle-valve actuator” unit.

The electric throttle-valve actuator is activated by the engine management system with a pulse-width modulated signal.

Troubleshooting

The following monitoring functions are processed in the two test modules ”electric throttle valves” and ”electric throttle valve potentiometers”:
  • Control units internal fault: Throttle valve
  • Throttle-valve faults, general
  • Fault in throttle-valve adaptation or start check
  • Function of both throttle valve potentiometers defective (general, signals implausible, plausibility with regard to air mass)
  • Throttle valve actuator is sluggish or jams (temporarily or permanently)
  • Activation of throttle-valve actuator defective

Service note

In contrast to earlier generations of the S54 engine, learning the throttle-valve position is no longer required following replacement of the control unit. The positions are automatically learned by the MSS70 control unit.
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