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© Scania Industrial & Marine Engines
DEC2 CONTROL SYSTEM
This engine has an injection pump with an electromagnetic actuator which
adjusts the control rack to give the correct amount of fuel.
The system which controls the pump is called DEC2 (Digital Engine Control,
generation 2).
The control unit (DEC2) continuously receives signals from sensors for
engine speed, charge air temperature and pressure, coolant temperature, oil
pressure, throttle position and control rack travel in the injection pump. Using
this input data and a control program, the correct amount of fuel for the
current operating conditions can be calculated.
The system’s sensors may be used only for DEC2, not for other instruments
or other monitoring purposes.
The control unit contains monitoring functions to protect the engine in the
event of a fault which would otherwise damage it. Faults and the more
important monitoring functions are indicated on the control unit in the form
of light emitting diodes. See illustration on page 14 for a description.
In case of a fault, the Power - or Shutdown indicator on the DEC2 control
unit as well as the main indicator lamp on the main supply box and the
instrument panel will illuminate.
If a fault has been indicated on the main indicator lamp the operator can
determine the cause of the fault with the help of the LEDs on the control unit
and the troubleshooting schedule on page 17, and carry out the required
investigation and remedy.
Depending on the nature of the fault, the control system will take different
actions to protect the engine such as reducing the power output, keeping the
engine running at a constant low speed or, in case of a function impairing
fault, shutting down the engine (Shutdown).
To enable readout of LED fault codes there is a lamp test/fault code switch
located in the main supply box near the control unit.
A PC based program is also available to help service personnel to detect and
rectify faults and to adjust certain parameters in the operating program.
Diagnostics and changes to programs must only be performed by
authorized personnel.
The locations of the sensors and monitors that send signals to the control unit
are shown in the illustrations on pages 13.
There is a description of the functions of the LEDs during normal operation
on page 14.
On page 15 there is a description of the functions of the LEDs in case of a
fault and actions in case of Power- and Shutdown indication.
Troubleshooting and fault code reading are described on pages 16 and 17.
