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Volkswagen Golf / Golf GTI / Golf Variant. Manual - part 758

If no faults can be found:
– Make sure that the drain valve -C- on the Pressure Tester

-1- is closed.

– The shut-off valves -A and B- on the Pressure Tester Kit -1-

are opened.

– Activate the fuel pump using the output diagnostic test mode

to build the fuel pressure.

– Close the shut-off valve -A- on the pressure gauge immedi‐

ately after the pressure has been reached. The lever is per‐

pendicular to the flow direction.

If the Pressure Drops Again (Leak on fuel tank side):
Proceed as follows to check residual pressure on the fuel delivery

unit. Refer to

⇒ page 97

If the Pressure no Longer Decreases (Leak on the Engine Side):

Note

Check for the leak on the engine-side. Repeat the residual pres‐

sure check. Close the shut-off valve -B- this time to determine if

there actually is a leak on the engine side.

– If there is a leak on the engine-side, check the fuel pipes and

high pressure pump for leaks.

If no malfunction is found, check the fuel injectors for leaks:
– Remove the spark plugs.
– Open the shut-off valve -A- and -B-. Activate the fuel pump

with the output diagnostic test mode.

– Check through the spark plug hole if fuel is collecting on the

piston crown due to a leaking fuel injector.

Residual Pressure in Fuel Delivery Unit, Checking:
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.

– Lift the tab -2- in the direction of the -arrow A- by using a finger

to reach between the floor panel and the fuel tank.

– At the same time, pull the Fuel Pump Control Module -1- on

the wiring harness -3- in the -direction of the arrow B- carefully

out of the mount.

– Remove the Fuel Pump Control Module - J538- toward the

inside between the fuel tank and the floor panel.

– Move the Fuel Pump Control Module - J538- to the side with

the connector connected.

– Pull the fuel line -1- off the flange. Disconnect the connector

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 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 Pressure Tester

Kit -1- are opened.

– Activate the fuel pump using the output diagnostic test mode

to build the fuel pressure.

– Close the shut-off valve -B- on the pressure gauge immedi‐

ately after the pressure has been reached. The lever is per‐

pendicular to the flow direction.

– Repeat the residual pressure check. Refer to

⇒ page 96

If the Pressure no Longer Decreases:
– Check the fuel line for leaks.

If the Pressure Drops Again:
– Open the fuel delivery unit -1-. Refer to

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

Installing”, page 52

– Make sure all hose connections -arrows- are connected.
– Check the fuel lines for leaks and damage.
If no Error Can Be Found:
– If the pressure retaining 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

8.1.6

Residual Pressure, Checking, Vehicles

with Engine Code CWVA

Special tools and workshop equipment required