Fuel Pump, Checking Electrically

Fuel Pump, Checking Electrically

Special tools, test equipment and auxiliary items







- 3307 fuel pump wrench
- VAG1348/3-2 with VAG1348/3A
- 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 behind storage shelf OK
- Fuel filter in good condition
- Ignition switched off

Test procedure
- 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 rear seat bench.







- Remove screws -arrows- for the cover.







- Carefully release 4-pin harness connector -arrow- 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 the 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 -1- and return line -2- and disconnect from closing flange (right side).

WARNING: The closing flange should only be opened if the fuel tank is maximum 1/4 full. Otherwise large quantities of fuel escape. Drain fuel tank if necessary.







- Remove closing ring for sender for fuel gauge using 3087 wrench.
- Remove closing flange with seal from tank opening.







- Make sure electrical connection between flange and fuel pump is good. Check for open circuit.

If there are no open circuits:
- Replace fuel pump delivery module.
- Install fuel pump delivery module.