Fuel Pump, Checking

Fuel Pump, Checking

Special tools, testers and auxiliary items required







- Hand multimeter V.A.G 1526 B or multimeter V.A.G 1715







- Voltage tester V.A.G 1527 B
- Connector test set V.A.G 1594 C

Conditions
- The fuses must be OK.
- Battery voltage must be at least 11.5 Volts.
- All electrical consumers such as lights and rear window defroster must be switched off.

Checking function and voltage supply
- Switch ignition on. Fuel pump must run for approx. 1 second.
- Switch ignition off.

If fuel pump does not activate:
- Remove luggage compartment floor cover.







- Connect voltage tester V.A.G 1527 B with adapter cables from test adapter kit V.A.G 1594 C to outer contacts of connector.
- Switch ignition on again, LED must illuminate for approx. 1 second.
- Switch ignition off.

If LED does not illuminate:
- Check actuation of fuel pump relay and check wiring for open circuits and short circuits: Vehicle diagnosis, testing information system VAS 5051

LED lights up (voltage supply OK):
- Remove fuel delivery unit.
- Check if electrical wiring between flange and fuel pump is connected and has continuity.

If no open circuits are found:
- Replace fuel delivery unit.

Checking current draw of Fuel Pump (FP)
- Pull connector off of flange of fuel delivery unit.







- Set multimeter to measuring range 20 A and connect it inline between contacts - 1 - of connector and fuel pump using adapter cables from connector test set V.A.G 1594 C.

NOTE: Also, the current clamp of the multimeter V.A.G 1715 can be attached to an adapter cable between the contacts - 1 - of the connector and the fuel pump.

- Connect contacts - 4 - of connector and fuel pump with an adapter cable from connector test set V.A.G 1594 C.
- Start engine and run at idle speed.
- Measure current draw of fuel pump:
Specification: 3.5 to 4.5 Amps.

If the measured value lies outside the specified value:
- Replace fuel delivery unit.