Check the supply pressure

Test conditions

The coolant temperature must be at least 85 ?� C.

Injectors are undamaged.

The fuel filter and fuel lines must not be clogged.

The order of execution of works

Remove the engine cover.

Remove the plug.

Connect a pressure gauge to the pump tandem as shown in Figure 2.336.

Start the engine and let it run at idle.

Connect the tester and select the operating mode ?�Fahrzeug-Eigendiagnose / self-test mode."

Press the button on the touch screen "01 - Motorelektronik / 01 - Engine electronics".

Press the diagnostic function "08 - Messwerteblock lesen / 08 - Read measured value block".

With the numbers on the keypad, set the instrument cluster "1" and confirm press Q.

Consider the value of the engine speed in display zone "1".

Raise the engine speed to 4000 ^min -1.

Watch the gauge pressure readings.

The nominal value of at least 7.5 bar.

If the specified value is not achieved, pinch the tube back the fuel line between the fuel filter and pump tandem using a hose clamp.

Raise the engine speed to 4000 ^min -1.

Watch the gauge pressure readings.

The nominal value of at least 10.5 bar

If the specified value is not achieved, then there is a loss of pressure in the pump-injectors.

Replace the O-rings of the pump injectors.

If the setpoint is not reached, replace the tandem pump.