Electronic Power Control System

Electronic Power Control System

With EPC, the throttle valve is not operated by a cable from the accelerator pedal. There is no mechanical connection between the accelerator pedal and the throttle valve.

The position of the accelerator pedal is communicated to the Engine Control Module (ECM) (J623) through the Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185) located in the accelerator pedal module.

The accelerator pedal position (driver's intention) is the main input unit for the Engine Control Module (ECM) (J623).

Operation of the throttle valve occurs through the an electric motor (throttle valve actuator) in the Throttle Valve Control Module (J338). This is true across the entire engine speed and engine load spectrum.

The throttle valve is operated by the throttle valve actuator according to the instructions of the Engine Control Module (ECM) (J623).

With the ignition switched on and the engine off, the Engine Control Module (ECM) (J623) activates the throttle valve actuator precisely according to the sensor for accelerator pedal position. This means, if the accelerator pedal is depressed half way, the throttle valve actuator opens the throttle valve to the same degree; i.e. throttle valve would be opened half way.

With the engine running (under load), the Engine Control Module (ECM) (J623) can open or close the throttle valve independently of the sensor for accelerator pedal position.

This means, that the throttle valve could be fully opened even though the accelerator pedal has only been depressed half way. This has the advantage of preventing torque losses at the throttle valve.

In addition to this, it results in significantly better values relative to emissions and consumption under certain load conditions.

The required engine torque can be achieved by the Engine Control Module (ECM) (J623) through the the optimal combination of throttle valve diameter and boost pressure.

It would be incorrect to think that "EPC" consists of only one or two components. EPC is much more of a system containing all components that contribute to recognizing, controlling and monitoring the position of the throttle valve, e.g. the Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185), Throttle Valve Control Module (J338), Electronic Power Control (EPC) Warning Lamp (K132), and the Engine Control Module (ECM) (J623).