Volkswagen Golf / Golf GTI / Golf Variant. Service manual - part 757

– Make sure that the drain valve -C- on the Pressure Tester

-1- is closed.

– The shut-off valves -A- and -B- on the -VAS6550- -1- are

opened.

– Connect the Vehicle Diagnostic Tester .
– Select the fuel pump output diagnostic test mode in OBD.

Note

♦

The fuel pump is now activated to build up the fuel pressure.

♦

If the output diagnostic test mode is performed several times

in succession, it may be necessary to briefly start the motor

before repeating the output diagnostic test mode.

– Read the fuel pressure on the pressure gauge.
• Specified value: approximately 4.0 bar
If the fuel pressure is OK, check the residual pressure. Refer to

⇒ “8.1.5 Residual Pressure, Checking”, page 95

 .

If the specified value is exceeded:
– The pressure relief valve in the fuel delivery unit is faulty.
– Replace the fuel delivery unit. Refer to

⇒ “2.2 Fuel Delivery Unit/Fuel Level Sensor, Removing and

Installing”, page 52

 .

If the specified value is not obtained:
Proceed as follows to check the fuel pressure at the fuel delivery

unit:
Golf Sportsvan:
– Remove the right rear seat. Refer to ⇒  Body Interior; Rep. Gr. 

72 ; Rear Seats; Bench Seat / Single Seat, Removing and In‐

stalling .

– Partially loosen the cover -1- in the carpet at the separating

line -arrow-.

– Do not separate the cover completely from the carpet so that

later it will be installed correctly.

– Only loosen so far that the cover can be folded up.
– Fold up the cover in the direction of the -arrow-.
Golf and Golf wagon:
– Remove the rear bench seat. Refer to ⇒  Body Interior; Rep.

Gr.  72 ; Rear Seats; Bench Seat / Single Seats, Removing

and Installing .

Continuation for All Vehicles:
– Unclip the sealing flange cover -1- at the tabs -arrows- using

the -3409- .

– Unclip the grommet -1- downward out of the cover -2-.
– Guide the cover -2- on the wiring harness -3- toward the rear.

– Remove the fuel lines -1- from the flange. Disconnect the con‐

nector couplings. Refer to

⇒ “4.1 Connector Couplings, Disconnecting”, page 62

 .

WARNING

The fuel line is under pressure.
Fuel poses a risk of injury to the eyes and skin.
Wear protective eyewear and protective clothing to avoid injury

and contact with skin. Place a cleaning cloth around the con‐

nection  point  before  loosening  hose  connections.  Carefully

open the connection point to release the pressure.

– Connect the -VAS6550- to the fuel delivery unit -1- using the

-VAS6550/3-4- .

– Connect the -VAS6550/3-3- between the -VAS6550- and the

fuel supply line -2-.

– Pull on the connector couplings to check them for secure fit.

– Make sure that the drain valve -C- on the Pressure Tester

-1- is closed.

– The shut-off valves -A and B- and -B- on the -VAS6550- -1-

are opened.

– Repeat the output diagnostic test mode to build up the fuel

pressure again.

If the specified value is obtained:
– Check the fuel lines for possible restrictions (kinks) or block‐

ages.

– Check the fuel line for leaks and damage.

If the specified value is not obtained:
– Remove the fuel delivery unit (refer to

⇒ “2.2 Fuel Delivery Unit/Fuel Level Sensor, Removing and

Installing”, page 52

 ) and inspect it for debris.

– Make sure all hoses -arrows- are connected.
– Check the fuel lines for possible restrictions (kinks) or block‐

ages.

– Check the fuel lines for leaks and damage.
If no error can be found:
– If the fuel pump is faulty, replace the fuel delivery unit. Refer

to

⇒ “2.2 Fuel Delivery Unit/Fuel Level Sensor, Removing and

Installing”, page 52

 .

8.1.5

Residual Pressure, Checking

Special tools and workshop equipment required
♦ Trim Removal Wedge - 3409-
♦ Pressure Tester Kit - VAS6550-
♦ Pressure Tester Kit - Adapter Set - Hose 3 - VAS6550/3-3-
♦ Pressure Tester Kit - Adapter Set - Hose 4 - VAS6550/3-4-
♦ Vehicle Diagnostic Tester
– Pay attention to all safety precautions. Refer to

⇒ “1 Safety Precautions”, page 1

 .

– Follow the guidelines for clean working conditions. Refer to

⇒ “3.1 Parking/Auxiliary Heater and Fuel System Clean Work‐

ing Conditions”, page 4

 .

• Fuel pressure is OK and the -VAS6550- is connected. Check

the fuel pressure. Refer to

⇒ “8.1.3 Fuel Pressure, Checking”, page 87

 .

– Connect the -VAS6550/2- between the fuel line from the fuel

tank and the shut-off valve -B- on the -VAS6550- .

– Connect the -VAS6550/1- between the fuel line leading to the

engine -1- and the shut-off valve -A- on the -VAS6550- .

Test Sequence:
– Connect the Vehicle Diagnostic Tester .
– Select the fuel pump output diagnostic test mode in OBD.

Note

♦

The fuel pump is now activated to build up the fuel pressure.

♦

If the output diagnostic test mode is performed several times

in succession, it may be necessary to briefly start the motor

before repeating the output diagnostic test mode.

– Read the fuel pressure on the pressure gauge.
• Specified value: greater than or equal to 4.0 bar
– End the OBD and turn off the ignition.
– Observe the decrease in pressure on the pressure gauge. The

pressure must not drop below 3.0 bar after 10 minutes.

If the pressure drops:
– Check all of the fuel lines for leaks and damage.