Fuel Pump, Checking

Fuel pump, checking
Special tools, testers and auxiliary items required





^ Multimeter V.A.G. 1526 or Multimeter V.A.G. 1715
^ Adapter set V.A.G. 1594A
^ Diode test lamp V.A.G. 1527

Requirements





^ Fuses must be OK
^ Battery voltage must be at least 11.5 V.
^ All electrical consumers, e.g. lights and rear window defogger, must be switched off.

Checking function and voltage supply
- Fold rear seat bench forward.
- Remove cover under bench seat.
- Briefly operate starter. Fuel pump must be heard to run.
- Switch off ignition.
- If the fuel pump does not run:





- Disconnect 4-pin connector from fuel delivery unit flange.
- Connect diode test lamp V.A.G. 1527 with adapter cables from V.A.G. 1594 to outer contacts of connector. LED must light up for approximately 2 seconds.
- LED does not light up:
- Check activation of fuel pump relay and wiring for an open or short circuit.Refer to Electrical Wiring Diagrams
- LED lights up (voltage supply OK):
- Remove fuel delivery unit .
- Check that electrical wiring between flange and fuel pump is connected and has continuity.
- If no open circuit can be found:
- Replace fuel delivery unit.
Checking current consumption of fuel pump
- Disconnect 4-pin connector from fuel delivery unit flange.





- Set multimeter measuring range to 20 A and connect multimeter in series between contacts - 1 - of connector and fuel pump using adapter cables from V.A.G. 1594A.

Note: The current pick-up clamp from multimeter V.A.G. 1715 can also be connected to an adapter cable connected between connector contacts - I - and fuel pump.

- Connect contacts - 4 - of connector and fuel pump using adapter cables from V.A.G. 1594A.
- Start engine and run at idling speed.
- Measure current draw at fuel pump- Specification- 3.5 ... 4.5 amps.
- If the values measured lie outside the specifications:
- Replace fuel delivery unit.