DDE 4.1 control units

Hardware

The M67 features two control unit (referred to as master and slave) that are interconnected by means of a ”private” CAN-bus.

Similar to the DDE 4.0, the control units are equipped with module connectors. Although the hardware of the control units is identical different data records have been programmed so the engine operation is not possible if the connectors are interchanged.

• Master = Black connector
  
• Slave = Dark blue plug connector
  

It is necessary to carry out EWS matching after replacing the master control unit. EWS matching is not necessary after replacing the slave.

Fault memory

Both control units feature a fault code memory similar to the DDE 4.0. Fault recognition takes place depending on the allocation of the function or of the input/output in the master or slave. The majority of fault codes are stored in both control units. This takes place by means of communication of both control units via the private CAN bus. Example: If the DDE master control unit recognizes a fault in the coolant temperature sensor, fault code 0115 is first entered in the master and fault code 0116 is then stored in the slave via the private CAN bus.

The DDE warning lamp and the limp-home program are activated when the following faults occur:

• Fault 0120, Pedal-travel sensor (Master)
  
• Fault 0121, Pedal-travel sensor (Slave)
  
• Fault 0220, Pedal-travel sensor 2 PGS (Master)
  
• Fault 1E40, Analog/digital converter test voltage (Master)
  

Software

Activation of the fuel injectors is divided over the two control units as follows:

• Master: Cylinders 2, 3, 5, 8
  
• Slave: Cylinders 1, 4, 6, 7
  

The further functions of the DDE 4.1 are divided over the two control units as follows:

Functions in master:

• Start control
  
• Volume calculation
  
• Vehicle speed control
  
• Preheater time control
  
• Presupply pump activation
  
• Presupply pressure monitoring
  
• A/C compressor activation
  
• Overheating protection
  
• Volume intervention for EGS, ASC, MSR
  
• Engine mount activation
  
• Activation of electric fan
  
• Boost pressure control with equalisation controller
  
• Coasting monitoring
  
• Volume limitation in the event of system fault
  
• Afterrunning test after ignition off
  
• Monitoring the above-specified functions and the corresponding components with subsequent fault code storage
  
  

Functions in slave:

• Engine speed acquisition and measurement
  
• Start synchronisation (gauging)
  
• Volume matching
  
• Control and monitoring of rail pressure
  
• Calculation of preliminary and main injection
  
• Idle speed control and idle speed matching
  
• Active judder damping (ARD)
  
• Smooth running control
  
• Overspeed recognition
  
• Deceleration fuel cutout
  
• Reversal protection for control units
  
• Monitoring the above-specified functions and the corresponding components with subsequent fault code storage