Fuel Pump, Electrical Checking

Fuel Pump, Checking Electrically

Special tools needed:
- VAG3217
- VAG1348/3A
with
VAG1348/3-2
- VAG1526 A
- VAG1594 A

Test conditions:
- Battery voltage at least 12 V
- Fuse 28 OK







- Relay 6 in central electric OK
- Fuel filter OK
- Ignition switched off.

Test sequence
- Open cover for fuse panel on left side of instrument panel.
- Remove fuse 28 from fuse panel (left row, fifth large fuse from the top).







- Connect remote switch VAG1348/3A with adapter wire VAG1348/3-2 to right terminal of fuse socket 28 -arrow-.
- Connect alligator clip to vehicle battery (+).
- Press remote switch button.
- Fuel pump must be heard to run.


NOTE: The fuel pump runs very quietly. Be sure to keep outside noise low when testing the fuel pump.


If you cannot hear the fuel pump run:
- Remove carpet liner in luggage compartment.
- Unscrew cover fuel pump flange.







- Unclip 4-pin connector and disconnect connector.







- Switch multimeter Fluke 83 to DC voltage range 20 V and using test wire from VAG1594 A, connect to terminal 1 (green/yellow) and 4 (brown) of connector.
- Press remote switch continuously and read voltage.
- Specified value: Approx. battery voltage

If specified value was obtained even so you could not hear the fuel pump run, remove the fuel pump flange as follows:


WARNING!
Fire hazard! Remove everything from the area that could ignite fuel or fuel vapor. fuel system is under pressure. Cover connection with rag and carefully release pressure by slowly opening the connection.







- Mark fuel return line -2- and fuel supply line -3- and remove from fuel pump flange.







- Remove threaded cap nut with wrench 3217.
- Lift flange and seal from tank opening.







- Check electrical connections between flange and fuel pump, check for continuity.

If wiring and connections are OK:
- Fuel pump is faulty; replace pump.