Fuel Pump, Checking

Fuel pump, checking

Special tools and equipment
- V.A.G1348/3A remote control with V.A.G1348/3-2 adapter cable
- V.A.G1526 or V.A.G1526 A hand-held multimeter
- V.A.G1594A connector test kit

All Wheel Drive (AWD) vehicles
- 3087 wrench for tank sensor

Front Wheel Drive (FWD) vehicles
- 3217 ring nut spanner

Test requirements:
- Battery voltage at least 12 V

- Fuse in fuse holder -S228- OK (position 28)

- Fuel Pump (FP) relay (position 4) in central electric behind driver's side storage compartment OK.
- Fuel filter OK
- Ignition switched off.

Test sequence

- Open cover of fuse box at left side of instrument cluster.

- Remove Fuse in fuse holder -S228- at fuse carrier (position 28) (left row, 5th large fuse from top).

- Connect V.A.G 1348/3A remote control connection using adapter cables from V.A.G1348/3-2 at right terminal of socket from Fuse in fuse holder -S228- (arrow).

- Connect alligator clip to vehicle battery B+.

- Press switch of remote control.

Operating noise of the pump must be audible in vicinity of fuel tank.

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

If no flowing noise can be heard:

All Wheel Drive (AWD) vehicles

- Remove rear seat bench.

- Remove cover at right beneath rear seat bench.

- Carefully disengage and disconnect electrical 4-pin harness connector (arrow).

Front Wheel Drive (FWD) vehicles

- Remove cover for connector flange below the luggage compartment carpet.

- Carefully disengage and disconnect electrical 4-pin harness connector (arrow).

Continue for all vehicles

- Connect multimeter between terminal 1 and 4 of harness connector for voltage measurement.

- Press switch of remote control.

Specified value: approx. battery voltage

If specified value is obtained, although no operating noise can be heard from pump:

WARNING!
Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.

All Wheel Drive (AWD) vehicles

- Mark fuel supply line -1- and fuel return line -2- and disconnect from connector flange (right side of vehicle).

WARNING!
Connector flange may only be opened when fuel tank is maximum 1/4 full. Otherwise, a large amount of fuel will spill out. Empty fuel tank if necessary.

- Use 3087 wrench to remove locking ring.

Front Wheel Drive (FWD) vehicles

- Mark fuel supply line -2- and fuel return line -1- and disconnect from connector flange.

- Use ring nut spanner 3217 to remove union nut.

Continue for all vehicles

- Pull connector flange and sealing ring from opening of fuel tank.

- Check whether electrical wires between flange and Fuel Pump (FP) are connected, and test for continuity if necessary.

If no malfunctions are found in wires:

- Fuel Pump (FP) faulty, replace fuel pump.

- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 04: Reset/Delete Diagnostic Data

- Generate readiness code. Audi Drive Cycle/Readiness Code

Checking fuel delivery

Special tools and equipment
- V.A.G1348/3A remote control with V.A.G1348/3-2 adapter cable
- Measuring container

Test requirements:
- Battery voltage at least 12 V
- Fuel filter OK
- Ignition switched off.

Test sequence

- Open cover of fuse box at left side of instrument cluster.

- Remove Fuse in fuse holder -S228- at fuse carrier (position 28) (left row, 5th large fuse from top).

- Remove engine cover (arrows).

WARNING!
Fuel system is under pressure! Before opening system, place rags around the connection point. Then release pressure by carefully loosening connection.

- Disconnect fuel return hose from line connection on fuel rail pipe.

- Connect assisting hose (arrow) on distributor pipe and hold in a measuring container.

- Operate remote control for 15 seconds (keep button pressed).

- Compare fuel quantity pumped with specified value.

*) Minimum delivery rate cm3/15 s

**) Voltage at fuel pump with engine off and pump running (approx. 2 volts less than battery voltage).

- Install fuel return line with a new hose clamp.