Volkswagen Workshop Service and Repair Manuals

Checking voltage supply

• ◆ Fuse No. 5 OK.
• ◆ Battery voltage OK.

Switch on ignition.
     The fuel pumps should be heard to operate briefly.

• Fuel pumps do not operate:

Switch off ignition.

• ‒ Connect V:A.G 1348/3A remote control .

Switch on ignition.

• ‒ Press remote control switch.
       The fuel pump should be heard to operate.

Should both pumps to operate:

• ‒ Consult the Current Flow Diagram to check the wire to the fuel pump relay. If necessary, renew the relay.

Should one pump fail to operate, check voltage supply at pump connection:

a) Lift pump (located in tank)

• ‒ → Remove connector from fuel level sender and connect LED Test Lamp V.A.G 1527 to red/yellow and brown wire using adapter wires from V.A.G 1594.

Switch ignition.

• ‒ Activate remote control.
  LED should light up.

Should LED fail to light up:

• ‒ Consult Current Flow Diagram and check wire to fuel lift pump. If necessary, renew lift pump.

b) Fuel pump (Installation location: underside of vehicle just forward of right side rear axle mounting)

• ‒ → Remove connector from fuel pump (depress wire clip) and connect LED Test Lamp V.A.G 1527 using adapter wire from V.A.G 1594.

Switch ignition.

• ‒ Activate remote control.
  LED should light up.

Should LED fail to light up:

• ‒ Consulted the CDF and check the wire to the fuel pump. Renew fuel pump is necessary.

Testing fuel pump delivery capacity and check valve

• ◆ V.A.G 1348/3A remote control connected => page 20-23 .

A - Checking delivery capacity

• ◆ Voltage supply OK.

• ‒ Remove cap from fuel filler pipe.

Lift pump

• ‒ Remove rear seat and cover.

• ‒ → Remove supply pipe -1- (black) and seal off.
• ‒ Attach a hose off max.350 mm in lenght to connection at sender from wich supply pipe was removed.
• ‒ Switch on ignition.
• ‒ Hold hose in a measuring glass.

• ‒ Press the remote control switch for 10 seconds.

• A quantity of least 300 cm3
• Should be delivered. If necessary, renew lift pump.

Fuel pump

• ‒ Lift pump OK.
• ‒ Pull supply pipe off fuel manifold.

• ‒ → Connect pressure gauge V.A.G 1318 to fuel supply pipe -1- (use union V.A.G 1318/10).
• ‒ Attach hose V.A.G 1318/1 to adapter V.A.G on pressure gauge and hold in measuring glass.

• ‒ Open valve on pressure gauge (lever in direction of flow) -Position A-.

Switch on ignition.

While activating remote control V.A.G 1348/3A, slowly close valve until pressure gauge indicates 2.5 bar.

• Do not change the valve setting further.

• ‒ Empty the measuring glass.
• ‒ Activate remote control switch for 30 seconds.

• ‒ → Compare quantity delivered with specification => diagram.

     *)     Minimum delivery cm3/30 seconds

     **)     Voltage at fuel pump with engine stationary and pump running (approx. 2 volts less than battery voltage).

Note:

Should specified quantity not be achieved:

• ◆ Fuel pipes bent or plugged.
• ◆ Fuel filter blocked, renew.
• ◆ Fuel pump defective, renew.

B- Testing check valve

Note:

In this test the fuel supply pipe connections between fuel pump and the connection of the pressure gauge V.A.G 1318 are also tested for leaks.

• ◆ Pressure gauge V.A.G 1318 connected => page 20-33 .

Switch on ignition.

• ‒ Press switch of remote control V.A.G 1348/3A at shorts intervals, until a pressure of
       approx. 3 bar
  has been reached (excessive pressure should be reduced to 3 bar be carefully opening valve a small amount).

• ‒ Note decrease in pressure. After 20 minutes pressure should not have fallen bellow 2.0 bar.

Where indicated, check fuel system connections for leaks and/or renew fuel pump.