Before commissioning When the engine brake is applied*, the constantly-open throttle valves are pressu- rised with compressed air which opens the valves. At the same time, the engine brake valve on the exhaust gas turbocharger is closed. i In emergency running mode (constant engine speed), the engine brake* can only be activated in overrun mode at a higher engine speed. The engine brake* is automatically deactivated again once the constant engine speed has been reached. 2 The engine brake* is controlled by the drive control unit ( page 33) or the ADM. The engine brake* is always inactive below 900 rpm to prevent the engine from stall- ing.
The engine brake* is also automatical- ly deactivated if the position sensor is triggered (e.g. if the accelerator pedal is depressed). 30 General remarks