Tandem and Fuel Pump Checking

Tandem and Fuel Pump Checking

• Tandem pump delivers fuel for cylinder bank 1 and Fuel Pump (FP) delivers fuel for cylinder bank 2.

Special tools, testers and auxiliary items required

• Torque wrench (5 to 50 Nm) (VAG 1331)

• Pressure gauge (VAS 5187) with 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.

• Pump-injector units OK

• Fuel filter and fuel lines must not be blocked

Test Sequence

Vehicles with test connections (Engine Code BKW)

- Connect test unit for tandem pump (VAS 5187) to test connection for cylinder bank 1 - 1 - or to test connection for cylinder bank 2 - 2 -.





Vehicles with test connections (Engine Code BWF)

- Connect test unit for tandem pump (VAS 5187) to test connection for cylinder bank 1 - 1 - or to test connection for cylinder bank 2 - 2 -.





Vehicles without test connections (Engine Code BKW)

- Remove fuel filter. Refer to --> [ Fuel Filter ] Fuel Filter.

- Connect test unit for tandem pump (VAS 5187) to supply line for cylinder bank 1 - 1 - or to supply line for cylinder bank 2.





- Install fuel filter. Refer to --> [ Fuel Filter ] Fuel Filter.

Continuation for All

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

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





- Start engine and run at idle speed.

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

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

- Enter "display group 1" via the number keypad and confirm input by pressing the Q button.

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

- Increase engine speed to 1500 RPM.

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

- Press the <- key twice.

- Press function "06 - End output".

If the specification is not obtained:

- Replace tandem pump or Fuel Pump (FP). Refer to --> [ Tandem and Fuel Pump ] Tandem and Fuel Pump.

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