Fuel Pumps, Checking

Diagnostic Procedures

Fuel Pumps, Checking

Test Conditions

• Observe safety precautions => [ Safety Precautions ] Safety Precautions.

• Observe rules for cleanliness => [ Clean Working Conditions ] Clean Working Conditions.

• Electrical fuel pump relays must be OK.

• Battery voltage (both batteries) must be at least 11.5 Volts.

• All electrical consumers such as, lights and rear window defroster must be switched off.

• For vehicles with automatic transmission, selector lever must be in " P".

• Parking brake must be engaged.

• Ignition switched off.

• The fuses must be OK:

Right instrument panel fuse holder

Observe safety precautions => [ Safety Precautions ] Safety Precautions.

Observe rules for cleanliness => [ Clean Working Conditions ] Clean Working Conditions.

Fuel pumps, checking function and voltage supply.

Fuel Pump, Right, Checking Electrical

• Observe safety precautions => [ Safety Precautions ] Safety Precautions.

• Observe rules for cleanliness => [ Clean Working Conditions ] Clean Working Conditions.

• Battery voltage at least 12.5 V

• Fuse 31 on fuse panel (SC31) (instrument panel, right) O.K.

• Fuel Pump (FP) Relay (J17) O.K. (on relay and fuse panel in right front footwell), Socket 4.

• Fuel filter OK.

• Ignition switched off.

Checking voltage supply

- Pry off right cover on instrument panel, using a screwdriver - arrow -.

- Pull out fuse 31 on fuse panel (SC31) (right instrument panel, middle row, first large fuse from top).

- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2) to the left socket terminal of fuse (SC31).

- Connect alligator clip to vehicle battery (+).

- Press switch on remote control.

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

• Fuel Pump (FP) runs quietly. Avoid surrounding noises while testing the fuel pump. If necessary, use a second technician to check.

If no operating noise can be heard:

- Remove trim for luggage compartment floor.

- Remove cover for right locking flange - arrows -.

- Carefully release and disconnect electrical harness connector - 2 - at right locking flange.

• Ignore - Pos. 1 -.

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

- Press switch on remote control.

• Specification: approx. battery voltage.

If specification is not obtained:

- Repair wire connection according to wiring diagram.

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If specification is obtained:

- Transfer Fuel Pump (FP) (G23) faulty, replace Fuel Pump unit, Fuel Pump (FP) unit, fuel level sensor, and suction jet pump (right side), removing and installing.

- Erase DTC memory from Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If specified value is obtained, although no running-noise can be heard at pump:

- Remove right fuel delivery unit.

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

If no malfunction is detected in the wiring:

- Fuel pump faulty. Replace right fuel delivery unit.

- Install right fuel delivery unit.

Checking current draw

• Voltage supply of Fuel Pump OK.

- Pull out fuse 31 on fuse panel (SC31) (right instrument panel, middle row, first large fuse from top).

- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2) to left socket terminal of fuse (SC31).

- Connect alligator clip to vehicle battery (+).

- Connect a commercially-available current clamp to remote control wire.

- Press switch on remote control.

- Measure current draw of fuel pump.

• Specification: approx. 8 A

If specification is not obtained:

• At a displayed current draw of 4 A, Fuel Pump (FP) runs dry.

Fuel Pump Test Sequence

If specification is not obtained:

- Determine and eliminate open circuit according to electrical schematics:

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If specification is obtained:

- Fuel Pump (FP) (G23) faulty, replace fuel delivery unit, fuel delivery unit, fuel level sensor and suction jet pump (right side), removing and installing.

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

Transfer Fuel Pump Test Sequence

Special tools, testers and auxiliary items required

• Remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2)

• Hand multimeter (V.A.G 1526 B) or (V.A.G 1526 A)

• Connector test kit (V.A.G 1594 C) or (V.A.G 1594 A)

• Vehicle Diagnostic, Testing and Information System (VAS 5051 A) with inductive pickup (50 A) (VAS 5051/9)

Test conditions

• Observe safety precautions => [ Safety Precautions ] Safety Precautions.

• Observe rules for cleanliness => [ Clean Working Conditions ] Clean Working Conditions.

• Battery voltage at least 12.5 V

• Model year 2003: Fuse 10 on fuse panel (SF10) (in relay and fuse panel in right of luggage compartment) O.K.

• From model year 2004: Fuse 2 on fuse panel (SF2) (in relay and fuse panel in right of luggage compartment) O.K.

• Fuel Pump (FP) 2 Relay O.K. (on relay and fuse panel in right of luggage compartment, Socket 3)

• Fuel filter OK.

• Ignition switched off.

Checking voltage supply

- Remove cover of right luggage compartment side trim - arrows -.

- Model year 2003: Pull out fuse 10 on fuse panel (SF10) (in relay and fuse panel in right of luggage compartment, Socket 10).

- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2) to right socket terminal of fuse 10 on fuse panel (SF10).

- From model year 2004: Pull out fuse 2 on fuse panel (SF2) (in relay and fuse panel in right of luggage compartment, Socket 2).

- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2) to right socket terminal of fuse 2 on fuse panel (SF2).

- Connect alligator clip to vehicle battery (+).

- Press switch on remote control.

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

• Fuel Pump (FP) runs quietly. Avoid surrounding noises while testing the fuel pump. If necessary, use a second technician to check.

If no operating noise can be heard:

- Remove trim for luggage compartment floor.

- Remove cover for left locking flange - arrows -.

- Carefully release and disconnect electrical harness connector - 2 - at left locking flange.

• Ignore - Pos. 1 -.

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

- Press switch on remote control.

• Specification: approx. battery voltage.

If specification is not obtained:

- Repair wire connection according to wiring diagram.

If specified value is obtained, although no running-noise can be heard at pump:

- Remove left fuel delivery unit.

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

If no fault is detected in the wiring:

- Fuel pump faulty. Replace left fuel delivery unit.

- Install left fuel delivery unit.

Checking current draw

• Voltage supply of Fuel Pump OK.

- Remove cover of right luggage compartment side trim - arrows -.

- From model year 2004: Pull out fuse 2 on fuse panel (SF2) (in relay and fuse panel in right of luggage compartment, Socket 2).

- Connect remote control (V.A.G 1348/3A) with adapter cable (V.A.G 1348/3-2) to right socket terminal of fuse 2 on fuse panel (SF2).

- Connect alligator clip to vehicle battery (+).

- Connect a commercially-available current clamp to remote control wire.

- Press switch on remote control.

- Measure current draw of fuel pump.

• Specification: approx. 8 A

If specification is not obtained:

• At a displayed current draw of 4 A, Fuel Pump runs dry.

- Determine and eliminate open circuit according to electrical schematics:

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.

If specification is obtained:

- Transfer Fuel Pump (FP) (G6) faulty, replace fuel delivery unit, fuel level sensor, and suction jet pump (left side), removing and installing.

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.