Contents: Backup modes of the throttle body…🠛 Power limitation mode 🠛 Electrical throttle opening…🠛 Mechanical throttle opening…🠛
The throttle valve unit with a servo drive provides regulation of idle speed and filling of the feeder cylinders with air. It consists of an electric motor and a potentiometric throttle valve position sensor with two conductive tracks.
At idle, the throttle position is set depending on the set idle speed, which depends on the number of high-power electrical consumers included (air conditioner) and engine operating conditions (air and coolant temperatures).
Pressing the accelerator pedal is converted into a request to change engine torque, in accordance with which the throttle opening angle and ignition timing will change.
To eliminate jerking, facilitate gear shifting and ensure safety, the throttle valve unit allows you to vary the engine torque.
Backup modes of the throttle body with servo drive
The throttle valve unit with servo drive can operate in three backup modes.
Power limitation mode
This mode is used in case of faults in electrical circuits for which there is a safe solution suitable for the injection system (malfunction of one of the two conductive tracks of the accelerator pedal position sensor or throttle valve unit).
In this mode, the acceleration intensity and the maximum throttle opening angle are limited.
Electrical throttle opening limitation
This mode is used in the complete absence of information about the position of the accelerator pedal, but the injection system ECU continues to control the filling of the engine cylinders with air (the throttle actuator remains controllable).
In this mode, the injection system ECU sets a specific engine speed for each gear and switches the engine to idle speed when the brake pedal is pressed.
Mechanical throttle opening limitation mode
This mode is used in case of malfunctions, as a result of which control over the throttle valve is lost (the valve does not respond to the movement of the accelerator pedal).
In this case, the throttle valve is in the initial position, and the injection system ECU limits the speed by interrupting the fuel injection.
Note: When switching to any of these modes, the injection malfunction indicator lamp lights up on the instrument panel.