Fuel Pump, Checking
Fuel pump, checking
Special tools and equipment
- VAG1348/3A remote control with VAG1348/3-2 adapter cable
- VAG1526 or VAG1526 A hand-held multimeter
- VAG1594A connector test kit
Requirements
- Battery voltage at least 12V.
- Fuse No. 28 OK
- Relay 6 in central electric OK
- Fuel filter OK.
- Ignition switched off.
Work 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 V.A.G 1348/3A remote control connection using adapter cables from VAG1348/3-2 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:
WARNING! 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 spanner 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.
- Install connector flange.
- 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
- VAG1348/3A remote control with VAG1348/3-2 adapter cable
- Measuring container.
Requirements
- Battery voltage at least 12V
- Fuel filter OK.
- Ignition switched off.
Work 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 V.A.G 1348/3A remote control connection using adapter cables from VAG1348/3-2 at right terminal of fuse socket No. 28 (arrow).
- Connect alligator clip to vehicle battery B+.
- Remove fuel filler cap from fuel filler tube.
- Remove engine cover.
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).