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Home/Volkswagen/Passat/Volkswagen Passat B5 facelift (2000-2005)/Repair manual/4.0L 8-CYL 4V Engine Mechanical, Fuel Injection Ignition, Engine Code(s): Bdp/Function
Contents Wiring diagrams Section: 4.0L 8-CYL 4V Engine Mechanical, Fuel Injection Ignition, Engine Code(s): Bdp All sections

Function Volkswagen Passat B5 facelift

4.0L 8-CYL 4V Engine Mechanical, Fuel Injection Ignition, Engine Code(s): Bdp 1 illustration ~513 words

Function

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

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

Fuel vapors disperse from the highest point of the fuel tank (at the filler neck) through the gravity valve (which closes at an inclination by 45 ° ) into the EVAP canister.

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

When driving with active Oxygen sensor regulation (engine warm), the Evaporative Emission (EVAP) Canister Purge Regulator Valve N80 is activated based on load and speed. The open duration is dependent on the input signals.

Without electricity (e.g. open circuit) the Evaporative Emission (EVAP) Canister Purge Regulator Valve remains 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 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. Fuel hoses in engine compartment must only be secured with spring type clips. The use of clamp or screw type clips is not permissible.

  1. The Spring Type Clip Pliers VAS 5024A are recommended for installing spring type clips.

Observe safety precautions --> Safety precautions when working on fuel supply system .

Observe rules for cleanliness --> Rules for cleanliness .

EVAP canister system components, disassembling and assembling --> EVAP canister system, assembly overview .

Scheme 190

Scheme 190: EVAP canister system, assembly overview
Scheme 190: EVAP canister system, assembly overview

1 - Bracket

2 - 8 Nm

3 - Disc

4 - Bolt

5 - Leak Detection Pump (LDP) V144

  1. Under wheel housing liner in rear left wheel housing

6 - Connector

  1. Black, 3-pin

7 - Connection piece

  1. Ensure seated tightly
  2. Press together at front to release

8 - Connecting hose

  1. Suction side
  2. Ensure seated tightly
  3. Secure with spring type clips

9 - Connecting hose

  1. Pressure side
  2. Ensure seated tightly
  3. Secure with spring type clips

10 - Connecting piece

11 - Air filter housing

  1. For Leak Detection Pump (LDP) V144

12 - Connector

  1. Black, 2-pin

13 - Vacuum line

  1. Ensure seated tightly
  2. Secure with spring type clips

14 - Evaporative Emission (EVAP) Canister Purge Regulator Valve N80

  1. Installed location: Arrow points in direction of flow

15 - Bracket

16 - Retaining ring

17 - Vent line

  1. Ensure seated tightly
  2. Secure with spring type clips

18 - Junction piece

19 - Connecting pipe

20 - EVAP canister

  1. In spare wheel well on vehicle floor

21 - 15 Nm

22 - Vacuum line

  1. Ensure seated tightly