Fuel Supply System VW-3.2

20 - 1

Fuel supply system components

Caution!

When doing any repair work, especially in the engine compartment, pay attention to the following due to clearance issues:

Route all the various lines (e.g. for fuel, hydraulics, EVAP system, coolant, refrigerant, brake fluid and vacuum lines and hoses) and electrical wiring so that the original positions are restored.

Ensure sufficient clearance to all moving or hot components.

Note:

Hose connections are secured with either spring-type or clamp-type clips.

Always replace clamp-type clips with spring-type clips.

Fuel hoses at engine must only be secured with spring-type clips. The use of clamp or screw type clips is not permissible.

Spring-type clip pliers VAS 5024 A or hose clip pliers V.A.G 1921 are recommended for installing spring-type clips.

The fuel system must be bled if the fuel delivery unit

Page 1 / 47 Volkswagen Touareg 3.2 - Fuel supply system components

is replaced 20-1, Fuel system, bleeding .

Observe safety precautions 20-1, Safety precautions when working on fuel supply system .

Observe rules for cleanliness 20-1, Rules for cleanliness .

Fuel tank with attachments, assembly overview 20-1, Fuel tank with attachments, assembly overview .

Fuel filter, assembly overview 20-1, Fuel filter, assembly overview

Schematic diagram of fuel lines and components in fuel tank 20-1, Schematic diagram of fuel lines and components in fuel tank

Fuel filter, replacing 20-1, Fuel filter, replacing

Fuel system, bleeding 20-1, Fuel system, bleeding

Fuel tank, emptying 20-1, Fuel tank, emptying

Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing 20-1, Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing

Fuel tank with attachments, removing and installing 20-1, Fuel tank with attachments, removing and installing

Check fuel pumps 20-1, Fuel pumps, checking

Parts of EVAP canister system:

Vehicles with engine code BAA and BMX 20-3, Evaporative emissions (EVAP) system (vehicles with engine code BAA and BMX)

Fuel tank with attachments, assembly overview

Caution!

During all repair procedures on the fuel tank, be aware of the following:

Route all the various lines (e.g. for fuel, EVAP system, or vacuum) and electrical wiring so that the original routing positions are restored.

Make sure that the Ground (GND) (-) strap between the fuel filler tube and body is securely

Page 2 / 47Fuel supply system components

fastened, to prevent electrostatic charging.


Fuel filler tube

With connection for Ground (GND) strap to body

Ensure seated tightly

To EVAP canister

Fuel tank

Support with engine/transmission jack V.A.G 1383 A when


removing

Fuel filter

Disassembling and assembling 20-1, Fuel filter, assembly overview

Locking ring, 145 Nm

Use wrench T10202 for removal and installation


Fuel delivery unit

Left side

Check fuel pump 20-1, Fuel pumps, checking

Fuel Level Sensor 3 G237

Left side

Clipped into bottom of tank

Suction jet pump

Left side


Protective cover

For bottom of fuel tank

Securing strap

Note installation position


20 Nm + 1 / 4 turn (90 )

Protective cover

For top of fuel tank


Suction jet pump

Right side


Fuel delivery unit

Right side

Check fuel pump 20-1, Fuel pumps, checking

Fuel Gauge Sender G

Right side


Flange

Right side

With fuel pressure regulator

With gravity valve

Individual components 20-1, Individual components of flange, right side

Note installed position on fuel tank 20-1, Installed position of sender flange on fuel tank

Vent line


Reservoir

Gravity valve

To pressure retaining valve


Individual components of flange, right side

1 - Connections for Fuel Pump (FP) G23 and Fuel Level Sensor G

2 - Fuel pressure regulator (4 bar)

3 - Ground (GND) wire

4 - Pressure regulator inlet (from fuel filter)

5 - Connection to left and right-hand fuel pump units (no pressure)

6 - Gravity valve

Installed position of sender flange on fuel tank

- Insert sender flange with marking - arrow - in direction of travel.

Fuel filter, assembly overview


Connection

For breather line

Flange

Left side

With fuel filter housing

Note installed position on fuel tank 20-1, Installed position of sender flange on fuel tank

Filter element

Oil seal

Replace


Ground (GND) wire


10 Nm

Supply line

To fuel pressure regulator

Connection

Filter supply from left fuel pump unit

Connection

Filter supply from left fuel pump unit

Ground (GND) connection

Sealing cap

For filter housing

Locating pin

Schematic diagram of fuel lines and components in fuel tank

- A - Left side of tank

- Arrow - indicates direction of travel

- B - Right side of tank


Gravity valve

Left side

Flange

Left side

Fuel filter

Gravity valve

Right side

Supply line

To fuel rail

Supply line for auxiliary heater


Flange

Right side

Fuel pressure regulator

Return line

From fuel pressure regulator

To fuel delivery units on left and right sides

Supply line for suction jet pump

Fuel delivery unit

Right side

Suction jet pump

Right side

Delivery line

Black

To fuel delivery unit on left side

Delivery line

Black

To fuel delivery unit on right side

Suction jet pump

Left side

Fuel delivery unit

Left side

Safety precautions when working on fuel supply system


Caution!



Make sure that the Ground (GND) (-) strap between the fuel filler tube and body is securely fastened, to prevent electrostatic charging.


For safety reasons, fuses - 13 - and - 14 - - arrow - must be removed before opening fuel system because fuel pump can be activated by door contact switch in drivers door.

Fuses 13 and 14 are located in fuse holder of electronic box in plenum chamber on left.

Always observe the following when removing and installing the sender for fuel gauge or the fuel pump (fuel delivery unit) from full or partially filled fuel tanks:

Warning!

Fuel supply lines are under pressure! Wear eye protection and protective gloves to avoid injuries and skin contact with fuel. Before removing from hose connection wrap a cloth around the connection. Then release pressure by carefully pulling hose off connection.


Already before starting work, switch on exhaust extraction system and place an extraction hose close to the sensor installation opening of fuel tank to extract escaping fuel fumes. If no exhaust extraction system is available, a radial fan (as long as motor is not in air flow) with a displacement greater than 15 m 3 /h can be used.

Prevent fuel from contacting skin! Wear fuel-resistant gloves!

Rules for cleanliness

When working on the fuel supply/injection system, pay careful attention to the following "5 rules" :

Thoroughly clean all connections and the surrounding area before disconnecting.

Place parts that have been removed on a clean surface and cover them. Do not use fluffy cloths!

Carefully cover over opened components or seal, if repairs are not performed immediately.

Only install clean components: Only unpack replacement parts immediately prior to installation. Do not use parts that have been stored loose (e.g. in tool boxes etc.).

When the system is open: Avoid working with compressed air if possible. Do not move vehicle unless absolutely necessary.

Fuel filter, replacing

Special tools, testers and auxiliary items required


Wrench T10202

Requirements

The fuel tank must be drained 20-1, Fuel tank, emptying , emptying fuel tank.

Fuses - 13 - and - 14 - - arrows - must be removed from their sockets.

Warning!


Work procedure

- Observe safety precautions before performing repair work 20-1, Safety precautions when working on fuel supply system .


- Cut open carpet on left side from point - A - to point - B - in pre-cut area - arrow - .

- Remove nuts - 1 - from cover. If necessary, unbolt backrest support - 2 - or support mounting.

Repair Manual, Body Interior, Repair Group 72, Rear seats

- Remove locking ring from left sender flange using fuel tank sender key T10202 .

- Remove flange from left side of tank.

- Empty fuel filter housing.


- Mark installation position of filter cover - 2 - using colored felt tip marker pen.

- Disconnect Ground (GND) wire - 1 - and unbolt filter cover - arrows - from housing.

If filter insert is to be replaced, ensure that the Ground (GND) connection contacts are not bent and have sufficient pretension.

Fuel system, bleeding



Hose clamps up to 25 mm Ø 3094

Remote control connection V.A.G 1348/3A

Diesel extractor VAS 5226

Not illustrated:

Adapter V.A.G 1318/20

Adapter V.A.G 1318/20-1


Adapter cable V.A.G 1348/3-3

Requirements

Battery voltage must be at least 11.5 V.

Fuel pump relays - 1 - and - 2 - for left and right fuel delivery units must be removed from their sockets.

Work procedure


- Remove cover in front of fuse holder.

- Connect remote control V.A.G 1348/3A with adapter cable V.A.G 1348/3-3 to connection - arrow - for fuel pump relay for right fuel delivery unit.

- Connect positive clamp of remote control to positive terminal in engine compartment.


- Thread adapter V.A.G 1318/20-1 onto adapter V.A.G 1318/20 .

- Turn valve on T-piece - arrow - counter-clockwise until completely open.

Warning!

Fuel supply lines are under pressure! Before opening the fuel system, connect diesel extractor VAS 5226 and release pressure.

- Unscrew bleed valve cap.

- Connect Adapter V.A.G 1318/20 with Adapter V.A.G 1318/20-1 and Diesel extractor VAS 5226 to bleed valve - 1 - .

- Turn valve (on T-piece) clockwise into bleed valve to stop.

- Check adapter and hose connection for leaks.

- Operate remote control V.A.G 1348/3A until fuel flows (free of air bubbles) from bleed valve.


- Turn valve on T-piece - arrow - counter-clockwise until completely open again.

- Clamp off hose from suction pump VAS 5226 (e.g. with hose clamps up to 25 mm Ø 3094 ) and pull hose off from Adapter V.A.G 1318/20-1 .

- Remove adapter V.A.G 1318/20 from bleed valve.

- Install cover onto bleed valve.

Fuel tank, emptying


Fuel siphoning unit VAS 5190


Polydrive key T10202

Not illustrated:

Assembly tool T10118

Work procedure

Warning!



- Open the fuel tank flap.

- Push suction hose - arrow - of fuel extractor VAS 5190 about 170 to 180 cm into fuel filler neck and extract fuel.

Note:


When no more fuel can be extracted the tank is emptied only enough for the sender flange to be opened without danger. The tank may be removed while containing the remaining fuel.

If work must be performed on the fuel pumps or fuel tank senders, proceed as follows:

- Cut open carpet from point - A - to point - B - in pre-cut area - arrows - .

- Remove nuts - 1 - from cover. If necessary, unbolt backrest support - 2 - or support mounting.

Repair Manual, Body Interior, Repair Group 72, Rear seats

Warning!



- Hold a cloth on connections for fuel supply line and auxiliary heater and pull off hose couplings.

Note:

Release connection by pressing button on hose coupling.

- Disconnect connectors for fuel pump and fuel gauge sender.

- Remove locking ring from sensor flange using wrench T10202 .

- Carefully pry out sender flange and raise it slightly.

- Insert suction hose of fuel siphoning unit VAS 5190 as deeply as possible in right and then left sides of fuel tank and extract fuel.

- For work on left side of fuel tank, proceed as described above.

- When breather line is pulled off, hose coupling button often cannot be pressed in. In that case, use assembly tool T10118 - arrow - .

For additional work on components inside of fuel tank, sensor flanges may remain removed.


If fuel tank needed only to be emptied, install sender flanges again.

- First check that sender flange seals are properly seated.

Note:

If seals are swollen with fuel, always replace.

- Insert sender flange with locating tab in direction of travel - arrow - .

- Tighten left and right locking rings using fuel gauge sender Wrench T10202 to 145 Nm.

Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing



Wrench T10202

Requirements



Connectors and wires for left and right sender flanges have been removed.

Locking rings for left and right sender flanges have been removed.

Work procedure



- Pull off connectors - 1 - and - 2 - , as well as hose couplings - 3 - and - 4 - under right sender flange.

- Remove sender flange with pressure regulator.

- Unclip black filler hose - arrow - from fuel delivery unit housing on left and right sides of fuel tank.

- Pull fuel supply line off fuel delivery unit - arrow - on left and right sides of fuel tank to suction jet pumps.

- Unscrew fuel delivery unit in bottom of fuel tank by turning approx. 90 to left.

Note:

The fuel delivery unit housing is filled with fuel. Fuel


may run out if the housing is tipped or tilted.

- Unclip fuel gauge senders on each side of fuel tank and pull them out.

- Unclip suction jet pumps from bottom on each side and remove with a slight turn.

- Pull out hose ends through left and right sender openings.

Fuel tank with attachments, removing and installing

Caution!







Wrench T10202

Torque wrench (5 to 50 Nm) V.A.G 1331

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

Engine/transmission jack V.A.G 1383/A

Fuel siphoning unit VAS 5190



Not illustrated:



Requirements



Removing


First, release fuel pressure as follows:



- Turn valve on T-piece - arrow - counter-clockwise until completely open.


- Screw adapter V.A.G 1318/20 hand tight onto bleeder valve.

- Connect hose from diesel extractor VAS 5226 as illustrated.


When fuel pressure has been released:

- Remove adapter V.A.G 1318/20 from bleed valve.

- Install cover onto bleed valve.

- Remove mufflers and mountings 26-1, Muffler with mountings .

- Remove driveshaft:

Repair Manual, Rear Final Drive, Repair Group 39, driveshafts, removing and installing

- Remove rear axle:

Repair Manual, Suspension, Wheels, Steering , Repair


Group 42, Rear axle, servicing

- Open fuel flap and remove fuel tank cap.

- Pull rubber gasket off filler neck.

- Remove securing bolts - 1 - on filler neck and pull off Ground (GND) wire - 2 - .

- Remove wheelhousing liner, rear right:

Repair Manual, Body Exterior, Repair Group 66, Wheel housing liner, removing and installing

- Unbolt cover plate - arrow - .


- Unclip fuel tank breather lines at securing clip attached on longitudinal member.

- Remove securing bolts for filler pipe - 1 - and EVAP canister - 2 - in wheel housing.

- Bend filler neck slightly downward and pull off breather line connections to EVAP canister.

Note:

Release connection by pressing button on hose coupling.

- Disconnect 3-pin connector from Evaporative Emission


(EVAP) Flap Motor Position Sensor V144 as well as 2-pin connector from Evaporative Emission (EVAP) Canister Purge Solenoid Valve 2 N115 .

- Disconnect Ground (GND) wire clipped to EVAP canister and remove canister.

- Separate fuel pump connectors, on left next to fuel tank.

- Remove securing straps with covers on left and right below fuel tank.

- Support fuel tank using engine and transmission jack V.A.G 1383 A and remove securing strap at center of fuel tank.

- Carefully lower fuel tank about 30 cm.

Warning!


- Reach between fuel tank and vehicle underbody and pull fuel supply and breather lines off sender flange. When pulling off fuel supply line, hold a cloth around fuel supply line.

Note:

This step eliminates having to cut open the carpeting in the vehicle interior in the vicinity of sender flange cover.

- Lower fuel tank.

Installing


Installation is performed in the reverse order of removal, noting the following:

Connections for breather and fuel lines must engage audibly when joined.

Make sure ventilation and fuel lines are not kinked when installed.

Secure fuel hoses with spring-type clamps.

Ensure fuel hoses are seated securely.

The Ground (GND) strap at the fuel filler tube - 2 - must be securely connected to the body.

Note:

Before fastening the fuel tank, check that the supply and ventilation lines are still clipped onto the fuel tank.

Fuel pumps, checking

Checking fuel delivery 20-1, Checking delivery rate

Checking current draw of fuel pumps 20-1, Checking current draw of fuel pumps

Checking fuel pump non-return valve 20-1, Checking fuel pump non-return valve



Polydrive key T10202

Pressure gauge V.A.G 1318



Hose V.A.G 1318/13

Pressure gauge adapter V.A.G 1318/17



Remote control connection V.A.G 1348/3A

Multimeter V.A.G 1715

Spring-type clip pliers VAS 5024A


Not illustrated:




Hose V.A.G 1318/24

Adapter cable V.A.G 1348/3-3

Measuring container

Wiring diagram

Checking delivery rate

Test conditions



Battery voltage at least 11.5 V


Test sequence

- Remove fuel filler cap from fuel filler tube.

- Connect remote control for VAG 1348 V.A.G 1348/3A with the adapter cable V.A.G 1348/3-3 to connection - arrow - for fuel pump relay for right fuel delivery unit.

- Connect positive clamp of - 1 - of remote control to positive (B+) terminal in engine compartment.


- Turn valve (on T-piece) counter-clockwise until completely open.

Warning!




- Connect Adapter V.A.G 1318/20 with Adapter V.A.G 1318/20-1 and Diesel extractor VAS 5226 to bleed valve - 1 - .


- When the fuel pressure has been released, the fuel system may be opened.

Checking delivery quantity of right pump

- Pull fuel supply hose - 1 - off fuel rail.

- Hold hose in measuring container - 2 - with capacity of at least 1000 cm 3 .

- Empty measuring container before making measurement.

- Operate remote control for 15 seconds: At least 3 fuel per 15 seconds must be delivered.

Checking delivery quantity of left pump


- Connect remote control for VAG 1348 V.A.G 1348/3A with adapter cable V.A.G 1348/3-3 to connection - arrow - for fuel pump relay for left fuel delivery unit.

- Empty measuring container before making measurement.

- Operate remote control for 15 seconds again. At least 3 fuel per 15 seconds must be delivered.

- Also test both fuel delivery units as follows:

- Connect Adapter V.A.G 1348/3-3 to fuel pump relay connections for left and right fuel delivery units.

- Operate remote control for 10 seconds: At least 800 cm 3 fuel per 10 seconds must be delivered.

If the minimum delivery rate is not attained:

- Check the fuel lines for possible restrictions (kinks) or blockages.

If lines are OK:

- Replace the fuel filter:

If the delivery rate has been attained but nevertheless you suspect a fuel supply system malfunction (e.g. intermittent failure of fuel supply system):

- Check current draw of fuel pumps 20-1, Checking current draw of fuel pumps .

Checking current draw of fuel pumps

- Check current draw of each fuel pump separately as follows:

- Reconnect all disconnected fuel lines.


- Connect current clamp of multimeter V.A.G 1715 to the wire of the 4-pin connector contact - 1 - - arrow - from wiring harness to right fuel delivery unit.

- Start the engine and run at idle speed.

- Measure current draw of fuel pump. Specification: max. 11 amps.

If the current draw is exceeded:

Warning!


- Right fuel pump is faulty. Replace fuel delivery unit 20-1, Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing .

- Repeat test on left fuel delivery unit.

If the current draw is exceeded:

- Left fuel pump is faulty. Replace fuel delivery unit 20-1, Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing .

Note:

If malfunction in fuel system is sporadic, test can also be performed during a road test, but a second person is required.

Checking fuel pump non-return valve

Conditions

Remote control for VAG 1348 V.A.G 1348/3A is still connected.


Note:

With this check, the fuel supply line connections from the fuel delivery units to the point at which the pressure gauge V.A.G 1318 is connected will be checked for leaks at the same time.

Test sequence

- Turn valve on T-piece of adapter V.A.G 1318/20 counter-clockwise until completely open.

- Connect pressure tester V.A.G 1318 to breather valve - 1 - as shown using adapter V.A.G 1318/20 , V.A.G 1318/20-1 , V.A.G 1318/9 and diesel extractor VAS 5226 .

- Screw valve on T-piece of adapters V.A.G 1318/20 clockwise into bleed valve to stop.

- Open shut off tap of pressure tester and operate remote control briefly to bleed air.


- Then, close pressure gauge shut-off tap - arrow - (lever perpendicular to direction of flow).

- Operate remote control at short intervals, until a pressure of approx. 4 bar has built up.

Warning!

Danger of spray when opening the shut-off tap diesel extractor VAS 5226 must be connected.

- If pressure builds up too high, lower excess pressure by carefully opening the shut-off tap.

- Watch pressure drop on gauge. After 10 minutes the pressure must not drop below a 3.0 bar decrease.

If the pressure drops:

- Check fuel lines and connections to fuel tank for leaks.

If no fault is detected in the wiring:

Warning!


- In addition, wrap a cloth around the connection to catch fuel which runs out.

- Remove pressure gauge V.A.G 1318 with adapters .

Checking non-return valve of right pump

Test conditions



Test sequence

- Disconnect 4 pin connector from the left flange

- Remove locking ring from left sender flange (fuel filter) using fuel tank sender key T10202 .

- Carefully pry up sender flange and raise it slightly.

- Disconnect connector next to fuel filter for attaching pressure tester V.A.G 1318 .

- Pull fuel supply hose - 2 - from right fuel delivery unit off fuel filter - 1 - .

- Let fuel from connecting piece - 1 - flow back into tank.


- Close pressure gauge shut-off tap - arrow - (lever perpendicular to direction of flow).

- Connect pressure tester V.A.G 1318 with adapter V.A.G 1318/7 , hose adapter V.A.G 1318/13 and adapter V.A.G 1318/17 as shown.

Note:

Ensure that fuel supply line connection engages audibly when joined.

- Attach connectors to the filter housing and flange again.

- Connect remote control for VAG 1348 V.A.G 1348/3A with the adapter cable V.A.G 1348/3-3 to connection - arrow - for fuel pump relay for right fuel delivery unit.




- Right fuel pump is faulty. Replace fuel delivery unit 20-1, Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing .


To change pressure tester set-up for left fuel pump:

- Open lever of pressure tester and let fuel flow back to fuel tank through hose V.A.G 1318/13 .

Checking non-return valve of left pump

- Pull fuel supply hose - 2 - from left fuel delivery unit off fuel filter - 1 - .

- If necessary, disconnect the connectors from the flange and filter housing and then attach pressure tester V.A.G 1318 .

- Close pressure gauge shut-off tap - arrow - (lever perpendicular to direction of flow).


- Connect pressure tester V.A.G 1318 with adapter V.A.G 1318/7 , hose adapter V.A.G 1318/13 and adapter V.A.G 1318/24 as shown.

Note:

Ensure that fuel supply line connection engages audibly when joined.

- Connect remote control for VAG 1348 V.A.G 1348/3A with adapter cable V.A.G 1348/3-3 to connection - arrow - for fuel pump relay for left fuel delivery unit.




- Left fuel pump is faulty. Replace left fuel delivery unit 20-1, Fuel delivery unit, fuel gauge sender and suction jet pump, removing and installing .


- Open lever of pressure tester and let fuel flow back to fuel tank through hose V.A.G 1318/13 .

- Remove pressure gauge V.A.G 1318 with adapters .


20 - 2

Electronic power control (EPC)

Bracket

Connector

Black, 6-pin

10 Nm

Throttle Position (TP) Sensor G79 with Accelerator Pedal Position Sensor 2 G185

Not adjustable

Remove footwell cover to remove sensor

Page 1 / 2Electronic power control (EPC)

Functions of EPC system

The position of the accelerator pedal is transmitted to the engine control module via two accelerator pedal position senders (adjustable resistances, accommodated in one housing), that are connected to the accelerator pedal.

The position of the accelerator pedal (driver controlled) is a main input for the engine control module.

Operation of the throttle valve occurs via an electric motor (throttle valve actuator) in the throttle valve control module. This is true across the entire engine speed and engine load spectrum.

The throttle valve is operated by the throttle drive according to the instructions of the Engine Control Module (ECM).

With the engine at standstill and the ignition switched on, the Engine Control Module (ECM) activates the throttle valve actuator precisely according to the specifications of the Throttle Position (TP) Sensor. This means, if the accelerator pedal is depressed half way, the throttle drive opens the throttle valve to the same degree; i.e. throttle valve is then opened approx. half way.

With engine running (under load) the engine control module can open and close the throttle valve independently of the accelerator pedal position sender.

This means. the throttle valve can already be completely opened, although the accelerator pedal is only depressed half-way. An advantage of this is that throttle losses at the throttle valve are avoided.

Aside from that, it results in clearly better pollutant output and consumption values under certain load conditions.

According to torque requirement outputs from the various components (e.g. air conditioning, automatic transmission, ABS/ESP...), the engine control module calculates a throttle valve open angle that is optimal for a respective situation.



Page 2 / 2Electronic power control (EPC)

20 - 3

Evaporative emissions (EVAP) system (vehicles with engine code BAA and BMX)

EVAP canister system components, assembly overview 20-3, EVAP canister system, assembly overview



Function

Depending upon air pressure and ambient temperature - more or less fuel vapors will form in the fuel tank.

The evaporative emissions system prevents these HC-emissions from dispersing into the atmosphere.

Fuel vapors pass from the highest point in the tank (on the filler neck) through the expansion tank and into the EVAP canister.

The activated charcoal in the canister stores these gases like a sponge.

When driving with active Lambda regulation (engine warm), the Evaporative Emission (EVAP) Canister Purge Regulator Valve N80 and the Evaporative Emission (EVAP) Canister Purge Solenoid Valve 2 N115 , are activated by Engine Control Module based on load and speed. The open duration is dependent on the input signals.

When purging (recovery of the activated charcoal), the intake manifold vacuum sucks fresh air in through the vent connection of the EVAP canister. The fuel vapors stored amongst the activated charcoal and fresh air are proportionately supplied to be burned.

Without electricity (e.g. open circuit) the Evaporative Emission (EVAP) Canister Purge Regulator Valves remain closed. The EVAP canister is not purged.

Function description of leak diagnosis

The EVAP system (including fuel tank) is equipped with leak diagnosis. The leak diagnosis will detect whether the system is leaking.

The diagnosis operates by pressurizing the system and should detect leaks where the damage exceeds 1 mm in

Page 1 / 5Evaporative emissions (EVAP) system (vehicles with engine code BAA and BMX)

diameter.

During the diagnostic, the Leak Detection Pump (LDP) V144 generates a positive pressure of approx. 30 mbar in the EVAP canister system. The pump will switch off when the pressure is attained. When the pressure falls to below a certain figure, the pump will switch on again. On Board Diagnostic monitors the switch intervals and stores a DTC in DTC memory if the intervals are too short.

Note:

Hose connections are secured with either spring-type or clamp-type clips.

Always replace clamp-type clips with spring-type clips.

Spring-type clip pliers VAS 5024 A or hose clip pliers V.A.G 1921 are recommended for installing spring-type clips.

EVAP canister system, assembly overview

Caution!




Ensure sufficient clearance to all moving or hot


components.

Reservoir

Right side

Gravity valve

Fuel filler tube

With connection for Ground (GND) strap to body

5 Nm

Bracket

Vent line

To vacuum connection on


intake manifold Item - 9 -


Leak Detection Pump (LDP) V144

Black connector, 3-pin

Connecting hose

Between air filter, Leak Detection Pump (LDP) V144 and Evaporative Emission (EVAP) Canister Purge Solenoid Valve 2 N115


5 Nm

Air filter housing

Clean if soiled

Rubber bushing


Replace if damaged

Evaporative Emission (EVAP) Canister Purge Solenoid Valve 2 N115

Black connector, 2-pin

EVAP canister

Component location: in front right wheelhousing

9 Nm

Vent line

To vacuum connection on intake manifold Item - 11 -



Connector

Black, 2-pin

Evaporative Emission (EVAP) Canister Purge Regulator Valve N80


Rubber bracket


Vent line


Pressure retention valve

Checking 20-3, Checking pressure retention valve on EVAP canister

Checking pressure retention valve on EVAP canister

The pressure retention valve is opened via the gravity valve (on expansion tank) for flow in both directions. ( - Arrow 1 - is the side toward the expansion tank).

On the other side, flow is possible in one direction only, to the EVAP canister side - arrow 2 - .


Documents

Fuel Supply System VW-3.2