Front Wheel Drive (FWD)

Fuel Pump, Checking Electrically

Special tools, test equipment and auxiliary items







- 3217 Ring Nut Spanner
- VAG1348/3A with VAG1348/3-2
- VAG1526 A
- VAG1594 A

Test requirements
- Battery fully charged (at least 12 volts)
- Fuse S228 OK (socket 28)







- Relay in position -4- in relay panel (central electric) behind storage shelf OK
- Fuel filter in good condition
- Ignition switched off

Test sequence
- Open cover for fuse panel on driver's side under instrument panel.
- Remove fuse 28 from relay panel (left-row, fifth large fuse from top).







- Connect VAG1348/3A remote switch with VAG1348/32 adapter cable to cavity for fuse 28 -arrow-.
- Connect test probe to Battery Positive Voltage (B+).
- Press remote switch.

- Fuel pump must run (pump will be audible)

NOTE: The pump is very quiet, make sure area is quiet while testing.

If the fuel pump does not run:
- Remove cover for closing flange under luggage compartment liner.

Limousine:
- Remove cover for sender for fuel gauge located under liner in luggage compartment.
- If necessary; fold the right rear seat back forward.

Avant:
- Remove cover for sender for fuel gauge located under liner in luggage compartment.

All:







- Remove cover -arrow- for fuel tank sender.







- Carefully release 4-pin harness connector and disconnect.







- Set multimeter (Fluke 83 or equivalent) to 20 volt DC range. Using adapter wire from VW1594 connector test kit connect to terminals -1- and -4- of harness connector.
- Press (and hold) remote switch and read voltage.
- Specified value: approx. Battery Positive Voltage (B+)


If specified value is not attained:
- Eliminate short circuit in wiring using wiring diagram.

Specified value is attained but the fuel pump does not run:

WARNING:
- Fire Hazard. Do not smoke, work near heaters or have anything in the area that could ignite the fuel or fumes.
- Fuel supply lines are under pressure. Before loosening any lines, cover the connection with a rag. Release the pressure by slowly separating the connection.







- Mark fuel supply line -2- and return line -1- and disconnect from closing flange.







- Remove union nut using 3217 ring nut spanner.
- Remove closing flange with seal from tank opening.







- Check that electrical wires between flange and fuel pump are connected and test for continuity.

If no wiring malfunction is detected:
- Fuel pump is faulty. Replace fuel delivery module.
- Install closing flange.