Rail-pressure sensor DDE 5.0/5.1

The rail-pressure sensor registers the fuel pressure in the rail and serves as a measured value transducer for volume metering and rail pressure control.

On the M47TU and M57TU, the rail-pressure sensor is mounted on the rail. On the M67, the rail-pressure sensor is mounted on the fuel-distribution pipe.

The DDE control unit supplies the sensor with ground (M_RDS) and a supply voltage of 5 V (U_RDS).

The pressure is picked up by a hole in the sensor and a corresponding measurement voltage (A_RDS) is sent to the DDE control unit).

Troubleshooting

If the rail pressure sensor is defective, the following faults may be stored:

• 3F30, Signal circuit break or short circuit to positive
  
• 3F31, Signal short circuit to earth
  

In addition, the rail-pressure sensor is monitored for a non-permitted offset in the unpressurized state.

Consequences:

• the DDE outputs a substitute value.
  
• the injection volume is limited.