Rail Pressure Control Valve DDE 6.0/6.2/6.3

The rail-pressure control valve is an electrically activated valve fitted in the M47TU/2 and M57TU/2 at the back end of the rail. On the M67TU, it is mounted on the fuel-distribution pipe.

When rail pressure control is active, the DDE controls the rail pressure control valve by means of a variable pulse duty factor in order to set the rail pressure to the level calculated by the DDE.

Function

Depending on the type of activation, the pressure control valve allows more or less fuel to flow from the high pressure side into the virtually depressurized return line. The more fuel the pressure control valve allows to flow into the return line, the lower the pressure build-up on the high pressure side.

Pulse duty factor, control signal current, rail pressure and volumetric flow through the valve are related to one another as follows:

Pulse duty factor	Control signal current	Pressure build-up	Volumetric flow into return line
High	High	High	Low
Low	Low	Low	High

Troubleshooting

If a fault is detected in the control of the rail pressure control valve, the following faults may be stored:

4332, Activation circuit break
4333, Excess temperature output stage
4340, Activation short circuit to B+
4351, Activation short circuit to B-

Consequence:

rail pressure control is changed over to volumetric flow regulation
The injection volume is limited