Fuel Pump, Electrical Testing

Fuel pump, electrical testing

Special tools and equipment





^ Ring nut spanner 3217
^ VAG1348/3-2
^ VAG1348/3A
^ VAG1526A
^ VAG1594A

Test requirements
^ Battery voltage at least 12.7 V
^ Fuse S228 OK (position 28)





^ Relay 4 in micro-central electric (in driver's footwell, left) OK
^ Fuel filter OK
^ Ignition switched off

Test sequence
^ Open cover of fuse box at left side of instrument panel.
^ Remove fuse S228 at fuse carrier (position 28, left row, 5th large fuse from top).





^ Connect VAG1 348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of socket from fuse -S228- (arrow).
^ Connect clamping terminal to B+.
^ Press switch of remote control.
^ Pump noise must be audible.

Note: Fuel Pump (FP) runs quietly. Surrounding noise should be avoided during test of the Fuel Pump (FP).

If no noise can be heard:

TT Coupe:
^ Remove rear seat bench.

TT Roadster:
^ Remove the rear panel side trim.





All:
^ Unscrew cover -1- at right (arrows).





^ Disengage 4-pin electrical harness connector and remove (arrow).





^ Connect multimeter between terminal 1 and 4 of harness connector for voltage measurement.
^ Press switch of remote control.
Specification: approximately battery voltage
If specified value is not obtained:
^ Locate and repair open circuit using wiring diagram.
Refer to Wiring Diagrams
If specified value is obtained, although no operating noise can be heard from pump, remove connecting flange as follows:
^ When removing the connection flange from the fuel pump, the fuel tank should be less than 1/3 full. If necessary, empty the fuel tank.
^ Note radio code (for vehicles equipped with coded anti-theft radio). Obtain if necessary.





Vehicles equipped with 4-cylinder engine
^ If installed, remove cover above battery.
^ Open battery protective casing (Velcro).





^ Switch ignition off and disconnect battery Ground (GND) strap (arrow).





Vehicles equipped with 6-cylinder engine
^ Switch ignition off and disconnect battery Ground (GND) strap (arrow) under trunk floor.

All:

WARNING: Fuel supply lines are under pressure! Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.





^ Disconnect fuel supply line -1- and fuel return line -2- (press release button).

WARNING: Fuel tank must be less than 1/3 full when removing fuel pump. If necessary, empty fuel tank.





^ Use ring nut spanner 3217 to remove and install
^ Remove connecting flange of fuel pump via opening of fuel tank and lay aside with wires connected.
^ Check whether electrical wires between flange and Fuel Pump (FP) are connected, check for continuity if necessary.

If no malfunctions are found in wires:
^ Fuel Pump (FP) is faulty; replace fuel pump.