Volkswagen 4-cyl. injection engine (1.8 and 2.0 l engine, chain drive). Manual (Edition 08.2018)

– Unbolt filler neck from body -arrows-.

– Remove bolts -1-.
– Unscrew securing strap and securing bolts -arrows-. When

doing this, support fuel tank with engine and gearbox jack -

V.A.G 1383 A- .

Installing
– With the aid of a second mechanic, guide the filler neck in be‐

tween rear axle and body. Then place fuel tank on engine and

gearbox jack - V.A.G 1383 A- .

– Raise fuel tank slowly up to installation position and secure it

in place.

Note

To secure the securing straps for the fuel tank, only bolts with

loose washers must be used. If different bolts are used, the se‐

curing straps might twist during tightening.

– Tighten the new bolts of the securing straps -arrows- and the

new bolt -1- to 25 Nm.

– Tighten securing bolts -arrows- for fuel filler neck to 8 Nm +

additional

/4 (90°) turn.

Further installation is carried out in reverse order of removal. Dur‐

ing this procedure, observe the following:
♦ Install breather lines and fuel lines free of kinks.
♦ Check earth connection on fuel tank and body to filler neck.
♦ Ensure that line connections are tight.
♦ After installing fuel tank, check that supply and breather lines

are still clipped onto fuel tank.

– Fill fuel tank with at least 5 litres of fuel.

WARNING

Risk of explosion of fuel tank. If a new or completely empty fuel

tank has been installed, it must be filled immediately with at

least 5 litres of fuel. The fuel pump must not be allowed to run

when the fuel tank is empty.

313

Fuel tank (Eos)

Safety precautions when working on fuel supply system

⇒ page 278

Comply with rules for cleanliness

⇒ page 280

Assembly overview - fuel tank (engine codes CBFA, CCTA,

CCTB)

⇒ page 316

Assembly overview - fuel tank (engine codes CAWA, CAWB,

CCZA, CCZB)

⇒ page 314

Drain fuel tank

⇒ page 318

Removing and installing fuel tank

⇒ page 322

6.1

Assembly overview - fuel tank (engine codes CAWA, CAWB, CCZA, CCZB)

1 - Securing bolt
2 - Cap

❑ Renew if damaged

3 - Earth connection

❑ Ensure firm seating

4 - 10 Nm
5 - Cable bracket
6 - 25 Nm

❑ Renew
❑ To secure the securing

straps for the fuel tank,

only bolts with loose

washers must be used.

If different bolts are

used, the securing

straps might twist during

tightening.

7 - Fuel

❑ When removing, sup‐

port using engine and

gearbox jack - V.A.G

1383 A- .

❑ Removing and installing

⇒ page 322

8 - Clamping washer
9 - Exhaust system retainer
10 - Securing strap

❑ Observe installation po‐

sition

❑ To secure the securing

straps for the fuel tank,

only bolts with loose

washers must be used. If different bolts are used, the securing straps might twist during tightening.

11 - Heat shield
12 - Supply line

❑ To fuel rail
❑ Ensure firm seating

Rep. gr.20 - Fuel supply system

13 - Fuel filter

❑ Fitting position

⇒ page 316

❑ Arrow points in direction of flow.

14 - Breather line

❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

15 - Seal

❑ Renew
❑ When installing, fit dry in fuel tank opening.
❑ Moisten with fuel only when installing flange.

16 - Fuel delivery unit

❑ Removing and installing

⇒ page 346

❑ Checking fuel pump

⇒ page 350

❑ Note installation position on fuel tank

⇒ page 315

❑ With fuel gauge sender - G-
❑ Removing and installing fuel gauge sender - G-

⇒ page 349

❑ Clean strainer if soiled

17 - Locking ring 110 Nm

❑ Ensure firm seating
❑ Remove and install using wrench - T10202- .

18 - Supply line

❑ black
❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

19 - Return line

❑ blue
❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

20 - Tank flap unit

❑ With rubber cup.
❑ Removing and installing ⇒ General body repairs, exterior; Rep. gr. 55 ; Tank flap unit; Removing and

installing fuel tank flap unit .

Installation position of fuel delivery unit
• Tab -2- on flange must be between lugs -1- and -3- on fuel

tank.

• -Arrow- points in direction of travel.

315

Location of fuel filter
Pin -2- on filter housing must engage in notch of guide -1- on filter

bracket.

6.2

Assembly overview - fuel tank (engine codes CBFA, CCTA, CCTB)

1 - Securing bolt
2 - Earth connection

❑ Ensure firm seating

3 - 11 Nm
4 - Rivet
5 - Protective plate

❑ Riveted as standard to

bottom clamp

❑ When replacing fuel

tank, hold protective

plate against filler pipe

and rivet to clamp

6 - Cable bracket

❑ Clipped onto protective

plate

7 - 25 Nm

❑ Renew
❑ To secure the securing

straps for the fuel tank,

only bolts with loose

washers must be used.

If different bolts are

used, the securing

straps might twist during

tightening.

8 - Fuel

❑ When removing, sup‐

port using engine and

gearbox jack - V.A.G

1383 A- .

❑ Removing and installing

⇒ page 323

9 - Clamping washer
10 - Exhaust system retainer
11 - Securing strap

❑ Observe installation position

12 - Heat shield
13 - Supply line

❑ To fuel rail

Rep. gr.20 - Fuel supply system

14 - Fuel filter

❑ Fitting position

⇒ page 318

❑ Arrow points in direction of flow.

15 - Vacuum line

❑ green
❑ From fuel system diagnostic pump - V144- to intake manifold.
❑ Clipped onto fuel tank
❑ Ensure firm seating

16 - Breather line

❑ white
❑ From activated charcoal filter to activated charcoal filter solenoid valve 1 - N80-
❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

17 - Seal

❑ Renew
❑ When installing, fit dry in fuel tank opening.
❑ Only when installing, moisten inside of flange with fuel

18 - Fuel delivery unit

❑ Removing and installing

⇒ page 346

❑ Checking fuel pump

⇒ page 350

❑ Note installation position on fuel tank

⇒ page 318

❑ With fuel gauge sender - G-
❑ Removing and installing fuel gauge sender - G-

⇒ page 349

❑ Clean strainer if soiled

19 - Locking ring 110 Nm

❑ Ensure firm seating
❑ Remove and install using wrench - T10202- .

20 - Return line

❑ blue
❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

21 - Cap

❑ Renew if damaged

22 - Tank flap unit

❑ With rubber cup.
❑ Removing and installing ⇒ General body repairs, exterior; Rep. gr. 55 ; Tank flap unit; Removing and

installing fuel tank flap unit .

23 - Supply line

❑ black
❑ Clipped onto side of fuel tank.
❑ Ensure firm seating

317

Installation position of fuel delivery unit
• Tab -2- on flange must be between lugs -1- and -3- on fuel

tank.

• -Arrow- points in direction of travel.

Location of fuel filter
Pin -2- on filter housing must engage in notch of guide -1- on filter

bracket.

6.3

Emptying fuel tank

Special tools and workshop equipment required
♦ Fuel extractor - VAS 5190-

♦ Special wrench - T10202-

♦ Torque wrench (40 to 200 Nm) - V.A.G 1332-
– Note safety precautions before beginning work

⇒ page 278

Rep. gr.20 - Fuel supply system

Emptying fuel tank with fuel pump intact

⇒ page 319

Emptying fuel tank if more than

/4 full

⇒ page 320

Emptying fuel tank if less than

/4 full

⇒ page 321

6.3.1

Emptying fuel tank when fuel pump is

intact

Special tools and workshop equipment required
♦ Adapter for fuel extraction - VAS 5190 /3-
♦ Test instrument adapter/DSO (5-pin) - VAS 5565-
♦ Remote control - V.A.G 1348/3A-

WARNING

♦ Fuel supply line is pressurised. Wear protective goggles

and protective clothing to avoid injury and contact with the

skin. Wrap a cloth around the connection before loosening

hose connections. Then release pressure by carefully

pulling hose off connection.

♦ Connect fuel extractor - VAS 5190- earth wire to vehicle

earth.

– Pull off supply line (metal coupling) -arrow- and catch escaping

fuel with a cloth.

Note

Press in securing ring to release the fuel lines.

– Connect fuel extractor - VAS 5190- with adapter for fuel ex‐

tractor - VAS 5190 /3- to fuel supply line.

– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

319

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– Pull off connector -arrow-.

– Connect test instrument adapter/DSO (5-pin) - VAS 5565- to

connector and fuel delivery unit.

– Connect remote control - V.A.G 1348/3A- to test instrument

adapter/DSO (5-pin) - VAS 5565- and to battery positive (+).

Note

This step serves only to have the fuel pump running when the

engine is stopped.

– Remove filler cap from fuel tank filler neck.
– Operate remote control - V.A.G 1348/3A- and shut-off tap on

fuel extractor - VAS 5190- until fuel tank is empty.

Caution

Do not allow the fuel pump run »dry«.

6.3.2

Emptying fuel tank if it is more than

full

Caution

Secure earth wire of fuel extractor - VAS 5190- to a bare metal

part of the body.

Rep. gr.20 - Fuel supply system

– Remove cotter -2- from shaft -1- of fuel extractor - VAS 5190- .
– At a distance of -a- = 820mm from the end of the hose, mark

extraction hose with insulating tape -arrow-.

– Push extraction hose into fuel tank until marking -arrow- on

hose coincides with filler neck.

Note

A ball valve is located at the lower end of filler neck in fuel tank,

which must not be damaged by the extraction hose -1-. Therefore

push hose into filler neck only as far as marking -arrow-.

– Empty fuel tank as far as possible.
– Carefully pull out extraction hose.

Note

♦

When no more fuel is extracted, the tank is emptied just

enough for the sender flange to be opened without danger.

♦

If the fuel tank has to be drained fully, proceed as follows:

⇒ page 321

6.3.3

Emptying fuel tank if it is less than

/4 full

– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

WARNING

Fuel supply line is pressurised. Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

321

– Pull off connector -arrow-.

– Pull fuel lines -1- and -2- off the flange.

Note

♦

Press in securing ring to release the fuel lines.

♦

On vehicles with auxiliary heater, the connector and the fuel

line of the metering pump - V54- must also be disconnected.

– Open locking ring using key - T10202- and raise flange slightly.

Caution

Do not cant key - T10202- and press against locking ring firmly.

If the key slips off, the fuel delivery unit can be damaged.

– Insert extraction hose of fuel extractor - VAS 5190- as deeply

as possible into fuel tank and extract fuel.

If fuel tank needed only to be emptied, reinstall sender flange

⇒ page 346

6.4

Removing and installing fuel tank

Special tools and workshop equipment required
♦ Torque wrench (5 to 50 Nm) - V.A.G 1331-

Rep. gr.20 - Fuel supply system

♦ Engine and gearbox jack - V.A.G 1383 A-

Remove fuel tank

⇒ page 323

Install fuel tank

⇒ page 325

6.4.1

Removing

– Note safety precautions before beginning work

⇒ page 278

– If necessary, empty fuel tank using fuel extractor - VAS 5190-

⇒ page 318

– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– Pull off connector -arrow-.

Note

For vehicles with auxiliary heater the metering pump - V54- con‐

nector must be separated additionally.

– Unscrew tank flap unit securing bolt and remove tank flap unit

⇒ General body repairs, exterior; Rep. gr. 55 ; Tank flap unit .

323

– Remove stiffener braces -A and B- ⇒ Running gear; Rep. gr.

42 ; Removing and installing stiffener braces .

– Remove centre and rear silencers.
– Remove heat shield for centre silencer.
– Remove rear right wheel.
– Remove rear right wheel housing liner ⇒ General body re‐

pairs, exterior; Rep. gr. 66 ; Removing and installing wheel

housing liner; Rear wheel housing liner .

– Unclip wire from filler neck -1-.
– Separate breather line -3- (only engine code CBFA, CCTA,

CCTB).

– Unbolt filler neck from body -2-.

– Detach breather line -1- (white) behind fuel tank. Push in re‐

taining ring to do this.

– Engine codes CBFA, CCTA, CCTB: Detach vacuum line -2-

(green) for the fuel system diagnostic pump - V144- behind

fuel tank. Push in retaining ring to do this.

WARNING

The fuel system is pressurised! Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

– Disconnect breather line -1- (white) and fuel line -2- (black) at

connecting point.

Note

♦

Press in securing ring to release the fuel lines.

♦

Vehicles with auxiliary heater, the fuel line of the metering

pump - V54- must also be separated.

♦

On vehicles with engine code CBFA, CCTA, CCTB, the vac‐

uum line (green) of fuel system diagnostic pump - V144- must

also be separated.

Rep. gr.20 - Fuel supply system

– Remove securing strap and securing bolts -arrows-. When

doing this, support fuel tank with engine and gearbox jack -

V.A.G 1383 A- .

– Carefully lower fuel tank.

6.4.2

Installing fuel tank

Install in reverse order of removal. During this procedure, observe

the following:
♦ To secure the securing straps for the fuel tank, only bolts with

loose washers must be used. If different bolts are used, the

securing straps might twist during tightening.

♦ Install breather lines and fuel lines free of kinks.
♦ Do not interchange supply line and return line (return line blue,

supply line black).

♦ Ensure that line connections are tight.
♦ Check earth connection on fuel tank and body to filler neck.
– Fill fuel tank with at least 5 litres of fuel.

WARNING

Risk of explosion of fuel tank. If a new or completely empty fuel

tank has been installed, it must be filled immediately with at

least 5 litres of fuel. The fuel pump must not be allowed to run

when the fuel tank is empty.

– Install stiffener braces ⇒ Running gear; Rep. gr. 42 ; Remov‐

ing and installing stiffener braces .

Specified torques:

Component

Fuel tank to body - M6 bolts

Fuel tank to body - M8 bolts

Renew

325

Repairing fuel supply (Passat, CC)

Note

♦

Fuel hoses on the engine must only be secured with spring-

type clips which conform to the production standard.

♦

Spring-type clip pliers - VAS 6499- or space saving hose clip

pliers - VAS 6362- are recommended for installation/removal

of spring-type clips.

Safety precautions when working on fuel supply system

⇒ page 278

Comply with rules for cleanliness

⇒ page 280

Removing and installing fuel delivery unit

⇒ page 326

Removing and installing fuel gauge sender - G-

⇒ page 330

Check fuel pump

⇒ page 331

7.1

Removing and installing fuel delivery

unit

Special tools and workshop equipment required
♦ Special wrench - T10202-

♦ Torque wrench (40 to 200 Nm) - V.A.G 1332-

Rep. gr.20 - Fuel supply system

Remove fuel delivery unit:

Caution

Condition:

• The fuel tank must not be more than

/4 full. This ensures

that the fill level is below the flange of the fuel delivery unit.

Procedure:

Note

♦

When replacing fuel delivery unit, check fuel tank for heavy

soiling and clean if necessary.

♦

Note safety precautions before beginning work

⇒ page 278

♦

Observe rules for cleanliness

⇒ page 280

♦

Assembly overview - fuel tank

⇒ page 281

– If necessary, empty fuel tank using fuel extractor - VAS 5190-

⇒ page 283

– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– First check that connector -A- is securely seated by pulling the

connector without pressing the catch. The connector can

cause a fault if it has not been fitted correctly.

– Now pull off connector.
– Check the contacts on the connector and on the fuel delivery

unit for damage.

WARNING

Fuel supply line is pressurised. Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

327

– Pull fuel line -B- off flange.

Note

♦

Press in securing ring to release fuel line.

♦

On vehicles with auxiliary heater, the connector and the fuel

line of the metering pump - V54- must also be disconnected.

– Open locking ring using key - T10202- .

Caution

Do not cant key - T10202- and press against locking ring firmly.

If the key slips off, the fuel delivery unit can be damaged.

– Lift flange.

– Separate coupling -A- and remove suction-jet pump -B-. Do

this by pressing lugs -arrows- together.

Note

Press in safety ring of coupling -A- to release fuel line.

– Pull seal and fuel delivery unit out of opening of fuel tank.

Note

♦

If delivery unit is to be renewed, drain old delivery unit before

disposal.

♦

Observe disposal regulations!

Install fuel delivery unit:

Caution

Do not bend float arm of fuel gauge sender - G- when installing.

– Insert fuel delivery unit (without suction-jet pump) into fuel

tank.

Rep. gr.20 - Fuel supply system

– Install suction-jet pump -B- and reconnect coupling -A-. Check

coupling is secured properly by pulling.

– Push flange onto fuel delivery unit.

Note

Ensure hoses are secured correctly.

– Now pull seal -A- over the flange and seat it in the opening of

the fuel tank.

– Moisten seal lightly with fuel and push flange into fuel tank.

– Observe installation position: Marking -A- points towards rear

of vehicle.

– Tighten locking ring using wrench - T10202- . Specified torque

⇒ Item 16 (page 282)

The remaining installation steps are carried out in the reverse se‐

quence of removal. During this procedure, observe the following:

329

♦ The -arrow- on the cover points forwards.
♦ Fuel lines are to be installed free of kinks.
♦ Ensure wiring/line connections are secured properly by pulling

back.

7.2

Removing and installing fuel gauge

sender - G-

Note

♦

Note safety precautions before beginning work

⇒ page 278

♦

Observe rules for cleanliness

⇒ page 280

♦

Assembly overview - fuel tank

⇒ page 281

Removing fuel gauge sender
– Remove fuel delivery unit

⇒ page 326

– Pull fuel gauge sender - G- slightly to side and upwards at the

same time.

– If the sender cannot be released in this way, the retaining tabs

-arrows- must also be pushed to the side slightly.

– Note colour co-ordination of cables for reinstallation.

Rep. gr.20 - Fuel supply system

– Release electrical connectors -1 to 3- and pull them off. Then

bend back locking lugs of connectors.

Installing:

– Connect connectors -1…3-. Observe colour co-ordination.
– Check connectors are secured properly by pulling.
– Insert fuel gauge sender - G- into guide on fuel delivery unit

and press down until it engages.

– Install fuel delivery unit

⇒ page 328

7.3

Checking fuel pump

Note

When replacing fuel delivery unit, check fuel tank for heavy soiling

and clean if necessary.

331

Special tools and workshop

equipment required

♦ Pressure gauge - VAS 6550-
♦ Remote control - V.A.G 1348/3A-
♦ Test instrument adapter/DSO (5-pin) - VAS 5565-
♦ Multimeter - V.A.G 1715-
♦ Special wrench - T10202-
♦ Measuring container, capacity at least 3 litres

7.3.1

Checking function and voltage supply

• Battery voltage at least 11.5 V.
• Fuse for fuel pump on fuse holder OK ⇒ Current flow diagrams,

Electrical fault finding and Fitting locations.

• Fuel pump control unit - J538- OK.

Rep. gr.20 - Fuel supply system

Note

♦

Function of fuel pump is checked using final control diagnosis.

♦

If the final control diagnosis is to be carried out several times

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

before repeating the final control diagnosis.

– Connect vehicle diagnostic tester as follows:
– Push diagnosis cable connector onto diagnosis connection in

driver footwell.

– Switch ignition on.
– Press buttons on display one after the other for

Vehicle

self-diagnosis

Engine electronics

and

Final con-

trol diagnosis

– Press right arrow button

►

on display up to final control diag‐

nosis for fuel pump electronics.

The fuel pump must now run slowly up to maximum speed.

Note

The fuel pump runs very quietly.

– Switch off ignition.
If fuel pump does not run:
– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Pull connector off fuel pump control unit - J538- .

– Check voltage supply between contacts -1- and -6- using mul‐

timeter - V.A.G 1715- .

• Specification: approx. battery voltage
Voltage supply not OK:
– Locate and eliminate open circuit referring to current flow di‐

agram ⇒ Current flow diagrams, Electrical fault finding and

Fitting locations.

Voltage supply OK:

333

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– First check that connector -A- is securely seated by pulling the

connector without pressing the catch. If connector was not in‐

serted correctly, repeat functional check of fuel pump.

– Now pull off connector.
– Check the contacts on the connector and on the fuel delivery

unit for damage.

WARNING

Fuel supply line is pressurised. Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

– Pull off fuel line -B- from the flange.

Note

♦

Press in securing ring to release fuel line.

♦

On vehicles with auxiliary heater, the connector and the fuel

line of the metering pump - V54- must also be disconnected.

– Open locking ring using key - T10202- .

Caution

Do not cant key - T10202- and press against locking ring firmly.

If the key slips off, the fuel delivery unit can be damaged.

– Check that electrical wires between flange and fuel pump are

connected.

If no open circuit can be found:
– Fuel pump defective, renew fuel delivery unit

⇒ page 326

Rep. gr.20 - Fuel supply system

7.3.2

Checking fuel pressure

Test conditions:
• Function of fuel pump has been checked

⇒ page 332

Test sequence

Note

♦

The fuel pressure must be checked by means of the final con‐

trol diagnosis. If the fuel pressure is measured at idling speed,

it may deviate from the specification.

♦

If the final control diagnosis is to be carried out several times

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

before repeating the final control diagnosis.

Note safety precautions before beginning work

⇒ page 278

– Observe rules for cleanliness

⇒ page 280

WARNING

Fuel supply line is pressurised. Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

– Pull off supply line (metal coupling) -arrow- and catch escaping

fuel with a cloth.

Note

Press in securing ring to release fuel line.

335

– Connect pressure tester - VAS 6550- to fuel supply line with

adapter - VAS 6550/1- and -VAS 6550/2- .

– Make sure that drain tap is closed and cut-off taps are open.
– Actuate fuel pump with final control diagnosis to build up fuel

pressure.

– Read fuel pressure on pressure gauge.
• Specification: 4.0 to 7.0 bar
If fuel pressure is OK, check holding pressure

⇒ page 338

If the specification is exceeded:
– Pressure limiting valve in flange defective, renew flange with

fuel filter

⇒ Item 15 (page 282)

If specification is not obtained
– Check fuel lines for possible restrictions (kinks) or blockages.
If no fault is found:
– Renew flange with fuel filter and pressure limiting valve

⇒ Item 15 (page 282)

– Repeat check.
If reading again does not match specification:
– Fuel pump defective, renew fuel delivery unit

⇒ page 326

7.3.3

Checking fuel pressure when the engine

is running (engine codes CCZA, CCZB,

CDAA, CDAB)

Note

♦

If a complaint is made about the vehicle's performance, the

reason may be that the fuel pressure is too low. Faults in the

high-pressure section may also be caused by inadequate fuel

pressure in the low-pressure section. This check determines

the fuel pressure in the high-pressure and low-pressure sec‐

tions during a road test. Fuel pressure in the high-pressure

section is read from the engine control unit. The lowest fuel

pressure is measured by the pressure tester - VAS 6550- and

reported to the vehicle diagnosis and service information sys‐

tem - VAS 5052 B- .

♦

This test can be part of “Guided Fault Finding” if an entry has

been made in the event memory. However, it can also be star‐

ted in the vehicle diagnosis and service information system -

VAS 5052 B- by means of “Functions and component

selection”.

Special tools and workshop equipment required
♦ Pressure gauge - VAS 6550-
♦ Hose adapters - VAS 6550/1- and -VAS 6550/2-
♦ Vehicle diagnosis and service information system - VAS 5052

B-

♦ Connector cable - VAS 5051/66-
– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

Rep. gr.20 - Fuel supply system

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– First check that connector -A- is securely seated by pulling the

connector without pressing the catch. The connector can

cause a fault if it has not been fitted correctly.

WARNING

The fuel line is under pressure.
Fuel poses danger of injury to eyes and skin.
Wear protective goggles and protective clothing to avoid injury

and contact with the skin. Wrap a cloth around the connection

before loosening hose connections. Then reduce pressure by

carefully opening the connection.

– Pull off supply line -arrow- and catch escaping fuel with a cloth.

Note

Press in securing ring to release fuel line.

337

– Connect pressure tester - VAS 6550- to fuel supply line with

adapter - VAS 6550/2- and -VAS 6550/1- .

– Fit connector cable - VAS 5051/66- to pressure tester - VAS

6550- and to vehicle diagnosis and service information system

- VAS 5052 B- .

– Make sure that drain tap is closed and cut-off taps are open.
– Switch on pressure tester - VAS 6550- .
If the fuel pressure test is carried out within “Guided Fault Find‐

ing”, follow the instructions of the diagnostic tester.
If the fuel pressure test is carried out without “Guided Fault Find‐

ing”, proceed as follows:
– Connect vehicle diagnosis and service information system -

VAS 5052 B- to vehicle.

– Select

Guided Fault Finding

in -VAS 5052 B- .

– Carry out identification of vehicle.
– Using the

GoTo

button, select the following menu options one

after the other:

♦

Function/component selection

♦

Drive

♦

Engine

♦

24 Mixture preparation/injection

♦

Mechanical components

♦

High-pressure pump

– Follow instructions on vehicle diagnosis and service informa‐

tion system - VAS 5052 B- .

WARNING

Test instruments and measuring equipment must always be

secured to the rear seat and operated by a second person from

this location.

7.3.4

Checking holding pressure

Note

If the final control diagnosis is to be carried out several times in

succession, it may be necessary to start the engine briefly before

repeating the final control diagnosis.

Rep. gr.20 - Fuel supply system

Prerequisites for check
• Fuel pressure OK and pressure tester - VAS 6550- connected.

Check fuel pressure

⇒ page 335

Test sequence
– Actuate fuel pump with final control diagnosis to build up fuel

pressure.

– Read fuel pressure on pressure gauge.
• Specification: 4.0 to 7.0 bar
– End self-diagnosis, and switch off ignition.
– Watch pressure drop on pressure gauge. Pressure must re‐

main above 3.0 bar for 10 minutes.

If the pressure drops further:
– Actuate fuel pump with final control diagnosis to build up fuel

pressure.

– After pressure has built up, close cut-off tap -B- of pressure

tester immediately. Lever is then at right angle to direction of

flow.

If the pressure drops again (leak on fuel tank side):
Leak must be sought on fuel tank side; proceed as follows:
– Check fuel line to flange

⇒ Item 15 (page 282)

for leaks.

If no fault is found on the fuel line:
Pressure limiting valve in flange defective or pressure retention

valve in fuel pump leaking.
– First replace flange with fuel filter

⇒ Item 15 (page 282)

and

repeat pressure retention check. If leak is still present, renew

fuel delivery unit.

If the pressure does not drop now (leak on engine side):

Note

Search for leak on engine side. Repeat holding pressure test. This

time, close shut-off tap -A- to check whether leak actually is on

engine side.

– If there is a leak on the engine side, carry out external check

of the fuel pipes and high-pressure pump for leaks.

If no fault can be determined, check the injectors for leaks:
– Remove spark plugs. Open shut-off valves -A- and -B-. Ac‐

tuate fuel pump with final control diagnosis.

– Check through spark plug holes whether fuel has collected on

the piston crown due to a leaking injector.

7.3.5

Checking fuel delivery rate (engine co‐

des CAWA, CAWB, CBFA, CCTA,

CCTB, CGYA, BZB)

Test conditions:
• Filling level in fuel tank above reserve

339

Test sequence
– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– First check that connector -A- is securely seated by pulling the

connector without pressing the catch. The connector can

cause a fault if it has not been fitted correctly.

– Now pull off connector.
– Check the contacts on the connector and on the fuel delivery

unit for damage.

– Connect test instrument adapter/DSO (5-pin) - VAS 5565- to

connector and fuel delivery unit.

– Connect remote control - V.A.G 1348/3A- to test instrument

adapter/DSO (5-pin) - VAS 5565- and to battery positive (+).

Note

This step serves only to have the fuel pump running when the

engine is stopped.

WARNING

Fuel supply line is pressurised. Wear protective goggles and

protective clothing to avoid injury and contact with the skin.

Wrap a cloth around the connection before loosening hose

connections. Then release pressure by carefully pulling hose

off connection.

Rep. gr.20 - Fuel supply system

– Pull off supply line (metal coupling) -arrow- and catch escaping

fuel with a cloth.

Note

Press in securing ring to release the fuel lines.

– Connect pressure tester - VAS 6550- to fuel supply line with

adapter - VAS 6550/2- . Hold adapter - VAS 6550/1- in a

measuring container.

– Make sure that drain tap is closed and cut-off taps are open.

WARNING

Danger of spray when shut-off tap is opened. Wear eye pro‐

tection and protective clothing to avoid injuries and skin con‐

tact. Hold container in front of open connection of pressure

tester.

– Operate remote control - V.A.G 1348/3A- . Then slowly close

shut-off tap -arrow- until a pressure of 4 bar is displayed on

pressure gauge. From this point on do not move position of

shut-off tap.

– Drain measuring container.

– The quantity delivered by the fuel pump depends on the bat‐

tery voltage. Therefore, connect multimeter - V.A.G 1715- to

wires -1- and -5- of adapter - VAS 5565- in addition.

– Operate remote control for 60 seconds while measuring volt‐

age at fuel pump.

341

– Compare quantity of fuel delivered with specification.
*) Minimum delivery rate cm³/60 s
**) Voltage at fuel pump with engine not running and pump run‐

ning.
Reading example:
During the test a voltage of 10.5 volts is measured. This equates

to a minimum delivery rate of approx. 1200 cm³/60 s
If specification is not obtained
– Check fuel line for possible restrictions (kinks) or blockages.
If no fault is found:
– Remove cap from fuel filler neck and repeat check. If fuel de‐

livery rate is now reached, check fuel tank breather.

If reading again does not match specification:
– Remove fuel delivery unit and check filter strainer for soiling.
– If no fault is found here either, renew flange with fuel filter.
– Repeat check.
If reading again does not match specification:
– Fuel pump defective, renew fuel delivery unit

⇒ page 326

If the fuel delivery rate has been attained but a fault is still sus‐

pected in the fuel supply system (e.g. intermittent failure of fuel

supply system):
– Measure current draw of fuel pump

⇒ page 344

7.3.6

Checking fuel delivery rate (engine co‐

des CCZA, CCZB, CDAA, CDAB)

Note

The fuel delivery rate must first be checked in the engine com‐

partment with the help of the function “Checking fuel delivery rate,

quick test”. If the minimum delivery rate is not achieved, a 2nd

measurement must be carried out at the flange of the fuel delivery

unit.

Checking fuel delivery rate in engine compartment:
– Connect vehicle diagnosis and service information system -

VAS 5052 B- to vehicle.

– Select

Guided Functions

in -VAS 5052 B- .

– Carry out identification of vehicle.
– Select

Engine

– Select

Checking fuel delivery rate, quick test

– Follow instructions on vehicle diagnosis and service informa‐

tion system - VAS 5052 B- .

Checking fuel delivery rate at flange:
Test conditions:
• The guided function “Checking fuel delivery rate, quick test”

has been carried out ⇒ Vehicle diagnostic tester

Rep. gr.20 - Fuel supply system

• The remote control - V.A.G 1348/3A- and test instrument

adapter/DSO (5-pin) - VAS 5565- have been connected to the

fuel delivery unit.

• Battery charger connected
• Filling level in fuel tank above reserve
Test sequence

WARNING

The fuel line is under pressure.
Fuel poses danger of injury to eyes and skin.
Wear protective goggles and protective clothing to avoid injury

and contact with the skin. Wrap a cloth around the connection

before loosening hose connections. Then reduce pressure by

carefully opening the connection.

– Pull supply line -arrow- off at flange and catch escaping fuel

with a cloth.

Note

Press in securing ring to release the fuel lines.

– Connect pressure tester - VAS 6550- to flange with adapter -

VAS 6550/2- . Hold adapter - VAS 6550/1- in a measuring

container.

– Make sure that drain tap is closed and cut-off taps are open.
– Press the remote control - V.A.G 1348/3A- and slowly close

shut-off tap -arrow- until a pressure of 4 bar is displayed on

pressure gauge. From this point on do not move position of

shut-off tap.

– Drain measuring container.

– The quantity delivered by the fuel pump depends on the bat‐

tery voltage. Therefore, connect multimeter - V.A.G 1715- to

wires -1- and -5- of adapter - VAS 5565- in addition.

– Operate remote control for 60 seconds while measuring volt‐

age at fuel pump.

343

– Compare quantity of fuel delivered with specification.
*) Minimum delivery rate cm³/60 s
**) Voltage at fuel pump with engine not running and pump run‐

ning.
Reading example:
During the test a voltage of 10.5 volts is measured. This equates

to a minimum delivery rate of approx. 1200 cm³/60 s
If specification is not obtained
– Remove cap from fuel filler neck and repeat check. If fuel de‐

livery rate is now reached, check fuel tank breather.

⇒ page 326

If fuel delivery rate has been attained, but nevertheless you sus‐

pect a fuel supply system fault (e.g. intermittent failure of fuel

supply system): Check fuel pressure with the engine running

⇒ page 336

7.3.7

Checking current consumption

– Remove bench seat ⇒ General body repairs, interior; Rep. gr.

72 ; Removing and installing bench seat .

– Remove cover -1- with fuel pump control unit - J538- -2- from

fuel delivery unit.

– First check that connector -A- is securely seated by pulling the

connector without pressing the catch. The connector can

cause a fault if it has not been fitted correctly.

– Now pull off connector.
– Check the contacts on the connector and on the fuel delivery

unit for damage.

Rep. gr.20 - Fuel supply system

Volkswagen 4-cyl. injection engine (1.8 and 2.0 l engine, chain drive). Manual (Edition 08.2018) - page 11