Fuel Pump, Testing Electrically

Fuel Pump, Testing Electrically

Special tools, testers and auxiliary items required

• Voltage tester (V.A.G 1527B)

• Multi-meter (V.A.G 1715) or vehicle diagnosis, testing and information system (VAS 5051)

• Wiring diagram

Test Conditions

• Battery voltage at least 11.5 V

• Fuses OK





• all electrical consumers, for example lamps and rear window defroster, switched off

Function and Voltage Supply, Checking

- Fold rear seat bench forward.

- Remove cover from fuel delivery unit.

- Switch ignition on. Fuel pump must run audibly for approximately 2 seconds.

- Switch off ignition.

If fuel pump does not activate:

- Disconnect 4 pin connector from flange at fuel delivery unit.

- Connect the voltage tester (V.A.G 1527) using the cables from the (V.A.G 1594) to the outer terminals of the connector.





- Switch ignition on.

LED must light up for approximately 2 seconds.

LED does not light up:

- Check activation of Fuel Pump (FP) relay and wires for open circuit and short circuit.

=> Vehicle diagnostic, testing, and information system (VAS 5051),

LED lights up (voltage supply OK):

- Fuel delivery unit, removing => [ Fuel Delivery Unit ] .

- Check if the electrical wiring between the flange and fuel pump is connected and has continuity.

If no open circuits are found:

- Fuel Pump (FP) faulty, replace fuel delivery unit => [ Fuel Delivery Unit ] .

Fuel Pump Current Draw, Checking

- Disconnect 4 pin connector on the fuel delivery unit.

- Set the multi-meter to measuring range 20 A and connect the adapter cables from (V.A.G 1594 A) between the terminal connectors - 1 - and the fuel pump in line.





• The Multi-meter (V.A.G 1715 ) electrical current probe or the vehicle diagnosis, testing and information system (VAS 5051) electrical current probe can be connected to an adapter cable between connector terminals - 1 - and the fuel pump.

- Connect the contacts - 4 - from the connector and fuel pump using the adapter cable from (V.A.G 1594 A).

- Start the engine and run at idle speed.

- Measure current draw of fuel pump.

Specified value: 3.5 to 4.5 amps

If the measured value lies outside the specified value:

- Replace fuel delivery unit => [ Fuel Delivery Unit ] .