Voltage Supply and Main Relay DDE 5.0

The power supply for the DDE control unit is provided via the 58-pin control unit connector.

Function

The power supply to the DDE control unit follows the following sequence when the ignition is switched on:

• At ignition ON, voltage is applied to the DDE control unit via terminal 15
  
• The DDE control unit switches on the DDE main relay via S_HR
  
• The DDE main relay switches terminal 30 via U_HR to the DDE control unit
  

Troubleshooting

The following faults are monitored in the voltage supply system:

• Fault 4660/4661: Voltage of power supply to DDE control unit too high/low
  
• Fault 4120/4121: DDE main relay switches off too soon/too late