Evaporative Emissions System: Diagrams

Evaporative Emissions (EVAP) System, Layout







1 - Intake manifold
2 - EVAP canister purge regulator valve 1 -N80-
3 - Test connection
4 - Fuel rail with fuel injectors
5 - Vent line
6 - Check valve
7 - Supply line
8 - Return line
9 - Ventilation line
- For ventilation during operation
10 - Fuel delivery unit
11 - Fuel tank
12 - Gravity valve
- Can only be replaced together with tank
13 - Ventilation - line
- For ventilation during tank filling
14 - Expansion-tank
- Can only be replaced together with tank
15 - Vent valve
16 - Cap
17 - Air cleaner
- For Leak Detection Pump (LDP) -V144-
18 - Leak Detection Pump (LDP) -V144-
19 - Evaporative - Emission (EVAP) Canister Purge Solenoid Valve -N115-
20 - Vacuum line
- From intake manifold to Leak Detection Pump (LDP) -V144-
21 - Pressure valve
22 - Connector
- For ventilation line
23 - EVAP canister
- Located in left front wheel well

Fig. 1 Test connection







Test connection -arrow- with green cap. Damage causes leaks and malfunction, recognized by EVAP canister.

EVAP canister purge regulator valve 1 -N80-, checking


NOTE: EVAP canister purge regulator valve is (electrically) normally closed.


Special tools and equipment
- VAG 1551/1552 Scan Tool with VAG 1551/3 adaptor cable

Test conditions
- Coolant temperature 80°C (176°F) minimum







- Fuse -S259- for Leak Detection Pump (LDP) -V144-, -arrow 2- OK

Function check
- Connect VAG 1551/1552 Scan Tool
- Start engine
- Press -0- and -1- buttons to select Address Word 01 "Engine electronics".

Display will appear as shown


Rapid data transfer HELP
Select function XX


- Press -0- and -8- buttons to select Function 08 "Read Measuring Value Block".
- Press -Q- button to confirm input.Display will appear as shown

Display will appear as shown


Read measuring value block HELP
Display group number XXX


- Press -0-, -5- and -2- buttons to select "Display group 52"
- Press -Q- button to confirm input.

Display will appear as shown (1 to 4 = Display fields)


Read measuring value block 52 ->
1 2 3 4


- Press 4 button to select "Basic setting" function
- Tank vent valve diagnosis will be initiated


NOTE:
- Engine must not be under load during this check because diagnostic procedure will be interrupted and will not start again until engine is revved-up briefly.
- When diagnosis is initiated by the Engine Control Module (ECM), display in field 4 changes from "Test OFF" to "Test ON" and solenoid valve will click.
- Allow engine to continue idling until specification "T V V OK" appears in display field 4.
- If display changes from "Test ON" to "Test OFF" during test, rev engine briefly and test will repeat

Display Group 52:

If "TVV not OK" appears in display zone 4:
- Initiate Output Diagnostic Test Mode and activate EVAP canister purge regulator valve -N80-.

If specification "TVV OK" is obtained:
- Press -> button.

Display will appear as shown

Rapid data transfer HELP
Select function XX

- Press -0- and -6- buttons to select Function 06 "End output".
- Press -Q- button to confirm input.