Exhaust flap DDE 6

When activated by the DDE control unit, the exhaust flap closes an exhaust tailpipe.

The DDE activates a pressure transducer that closes the exhaust flap by means of partial vacuum.

Function

Depending on the operating condition, the exhaust flap is closed in order to improve the acoustic pattern.

The exhaust flap is closed under the following conditions:

• when the particulate filter regeneration is not active:
  at 1100 rpm < speed < 2200 rpm and injection rate < 30 mg
  
• when the particulate filter regeneration is active:
  at speed < 2200 rpm, independent of injection rate at 2200 rpm < speed < 2400 rpm and injection rate < 40 mg at 2400 rpm < speed < 2600 rpm and injection rate < 30 mg at 2600 rpm < speed < 2750 rpm and injection rate < 25 mg
  

Troubleshooting

If a fault is detected in activation of the switchover valve, a corresponding fault is stored.