Piezo injectors DDE6.2/6.3

The fuel pressure in the rail is constantly applied to the injectors. Fuel is injected into the combustion chambers upon electrical activation by the DDE control unit.

Electrical control

M57TU/2:

On the injector high side (P_PIH1, P_PIH2), three cylinders are combined in a ”block”. The wiring is separate as far as the control unit. The cables are only combined into a ”bank” in the control unit.

Important: If a fault occurs on the high side, the fact that the wires are combined (P_PIHx) means that the cause may originate from any of the leads of the cylinder bank involved. In such cases, all injectors of the cylinder bank will fail.

M67TU:

On the high side and low side of the injectors, four cylinders are activated by a DDE control unit. On the injector high side (P_PIH1, P_PIH2), two cylinders are combined in a ”bank”. On the high side, the wiring to the control unit is separate. The cables are only combined into a ”bank” in the control unit.

Important: If a fault occurs on the high side, the fact that the wires are combined means that the cause of the fault may originate from any of the leads of the DDE control unit involved. In this case, all the injectors activated by this ”bank” will fail.

Troubleshooting

The following faults are covered in this test module:

• Energy consumption measurement
  
• Zero-quantity adaptation
  
• Wiring harness, short circuit on the negative side between two cylinders
  
• Selection switch (control unit internal fault)
  
• Chip (control unit internal fault)
  
• Activation unknown fault
  

• Bank activation short circuit to positive, earth, selection switch, etc.
  
• Cylinder activation short circuit to positive, earth, interrupt, high-impedance short circuit, etc.
  

Consequences:

Depending on number of failed injectors, the engine switches off.