Electric Throttle Valve ActuatorMany 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.
TroubleshootingThe 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