Tandem and Fuel Pump, Checking

Tandem and Fuel Pump, Checking

• The tandem pump delivers fuel for cylinder bank 1 and the fuel pump delivers fuel for cylinder bank 2.

Special tools, testers and auxiliary items required

• Torque Wrench (5-50 Nm) (V.A.G 1331)

• Pressure Gauge (VAS 5187)

• Adapter Set (VAS 5187/6)

• Vehicle Diagnostic, Testing and Information System (VAS 5051 A) with Diagnostic Cable

Test Conditions:

• Coolant temperature must be at least 85 °C (185 °F).

• Pump injector units are OK.

• Fuel filter and fuel lines must not be blocked.

Test Sequence:

Vehicles with Test Connection (engine code BKW)

- Connect the pressure gauge (VAS 5187) to the test connection for cylinder bank 1 - 1 - or to the test connection for cylinder bank 2 - 2 -.






Vehicles with Test Connections (engine code BWF)

- Connect the pressure gauge (VAS 5187) to the test connection for cylinder bank 1 - 1 - or to the test connection for cylinder bank 2 - 2 -.






Vehicles without Test Connections (engine code BKW)

- Remove the fuel filter. Refer to => [ Fuel Filter ] Removal and Replacement.

- Connect the pressure gauge (VAS 5187) to the supply line for cylinder bank 1 - 1 - or to the supply line for cylinder bank 2.






- Install the fuel filter. Refer to => [ Fuel Filter ] Removal and Replacement.

Continuation for all Vehicles:

Connect the vehicle diagnosis, testing and information system (VAS 5051 A) as follows:

- Open the cover - 1 - (if equipped) and connect the connector from the diagnostic cable to the data link connector.






- Start the engine and run at idle speed.

- On the vehicle diagnostic, testing, and information system , select the operating mode "Vehicle On Board Diagnostics". Then, go into engine control module (J623) with address word "01 - Engine electronics".

- Press the diagnostic function "08 - Read measuring value blocks".

- Enter "display group 1" via the number keypad and press Q to confirm.

- Read the idle RPM in "display field 1".

- Increase the engine speed to 1500 RPM.

- Observe the pressure displayed on the pressure gauge. Specified value: at least 7.5 bar.

- Press the bton two times.

- Press function "06 - End output".

If the specification is not obtained:

- Replace the tandem pump or fuel pump. Refer to => [ Tandem and Fuel Pump ] Tandem and Fuel Pump.

• After removing the pressure gauge from the tandem pump, tighten the supply line and plug to 27 Nm.