Two variable nozzle turbine chargers without a ”wastegate” are used for boost pressure control. They are operated by means of control levers on the turbine housings. The control levers are operated by electrical actuators (electric motors with worm gear and electronic control) that are mounted directly on the turbochargers. The actuators cannot be replaced separately.
The DDE master control unit activates both boost pressure actuators with square-wave signals with duty factors (= variable pulse width) between 5 and 95 %.
The control levers must move between minimum and maximum activation by 35° to 45° angle of rotation. Adjustment must take place rapidly.
The following faults may occur in the event of defects in the boost pressure control system.
Fault code 1470, ”boost pressure control”, negative control deviation
Fault code 1E30, ”boost pressure control” with following possible types of fault:
Fault code 1E31, ”boost pressure control” with following possible types of fault:
The fault types ”fault signal from boost pressure actuator 1/2” signify that the DDE control unit receives feedback from the boost pressure actuator indicating that a fault has occurred on the boost pressure actuator itself. This may be attributed to efficient voltage supply, overheating, mechanical blocking or a fault in the electronic control of the boost pressure actuator.
Consequences of fault occurring in the boost pressure control system:
Boost pressure control is also deactivated when following faults occur: