Fuel Pump, Checking

Fuel pump, checking

Special tools and equipment
- VAG 1348/3A remote control with VAG 1348/3-2 adapter cable
- VAG 1526 or VAG 1526 A hand-held multimeter
- VAG 1594A connector test kit

Test requirements:

- Battery voltage at least 12 V.






- Fuse No. 28 OK.






- Relay 6 in central electric OK.
- Fuel filter OK.
- Ignition switched off.

Test sequence

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

- Remove fuse No. 28 at fuse carrier (left row, 5th large fuse from top).






- Connect VAG 1348/3A remote control connection using adapter cables from VAG 1348/3-2 at right terminal of fuse socket No. 28 (arrow).

- Connect alligator clip to vehicle battery B+.

- Press switch of remote control.

Flowing noise of pump must be audible.

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:

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






- Release and disconnect 4-pin harness connector -1-.






- Switch V.A.G 1526 multimeter to measurement range direct current voltage measurement 20 V and connect terminal 1 (green/yellow) and 4 (brown) of harness connector using adapter cables from V.A.G 1594 A.

- Press remote control switch continuously and read out the voltage.

Specified value: approx. battery voltage

If the specified value is reached, although no operating noise from pump is audible, remove connector flange as follows:

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






- Mark supply line -2- and return line -3- and disconnect from connector flange.






- Use ring nut wrench 3217 to remove union nut.

- 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.

- Installing connector flange.

- Erase DTC memory of Engine Control Module (ECM).

- Generate readiness code.