The following vacuum diagrams are representative of diagrams and components used in the emission control systems of these vehicles. Because there are many different make, model, engine, transmission, and calibration-level versions, there are many more vacuum diagrams than can be provided here.
Always consult the emission label under the hood for the most accurate vacuum diagram for that specific vehicle.
If the label is missing, contact your local VW or Audi dealer for a replacement.
Fig. Audi A4 2.8L Vacuum Diagram
Key List for gnam 93224vwg70:
1.Brake booster
2. Check valve
3. Vacuum canister, for intake manifold change over valve
4. Check valve
5. Throttle body
6. Ignition coils
7. Vacuum reservoir, for intake manifold change over valve
8. Air cleaner
9. Intake manifold
10. Sensor for EVAP canister
11. EVAP canister
12. EVAP canister purge regulator valve
13. Fuel pressure regulator
14. T connector, only for vehicles with A/C and/or EGR
15. Check valve
16. T connector, only for vehicles with A/C
17. To A/C
18. Intake manifold change-over valve
19. EGR vacuum regulator solenoid valve
20. Sound dampener
21. EGR valve
Fig. Audi A4 2.7L Vacuum Diagram
Key List for gnam 93224vwg71:
1. To reservoir under right front wheel housing shell.
2. Air cleaner
3. Mass Air Flow (MAF) sensor
4. Evaporative Emission (EVAP) canister
5. Turbocharger engine bank 1
6. Combination valve for secondary air injection (AIR)
7. Secondary Air Injection (AIR) solenoid valve
8. Wastegate bypass regulator valve
9. Check valve for crankcase ventilation
10. Collector housing for crankcase ventilation
11. To power brake booster
12. Check valve (arrow indicates direction of flow through valve)
13. Secondary Air Injection (AIR) pump motor
14. Vacuum limiter valve
15. Fuel pressure regulator
16. To Leak Detection Pump (LDP)
17. Vacuum reservoir
18. Turbocharger engine bank 2
19. Pressure unit for boost pressure regulation
20. Combination valve for secondary air injection (AIR)
21. Check valve (arrow indicates direction of flow through valve)
22. Charge air cooler engine bank 2
23. Pressure hose engine bank 2
24. Recirculating valve for turbocharger
25. Cut out valve (mechanical circulation valve)
26. Connection hose
27. Pressure line engine bank 2
28. Connection hose for both charge air coolers
29. Check valve for crankcase ventilation
30. Connection hose
31. Cut out valve (mechanical circulation valve)
32. Pressure line engine bank 1
33. Pressure hose engine bank 1
34. Check valve (arrow indicates direction of flow through valve)
35. Evaporative Emission (EVAP) canister purge regulator valve
36. Charge air cooler engine bank 1
37. Pressure unit for boost pressure regulation
Fig. Audi A4 1.8L Vacuum Diagram
Key List for gnam 93224vwg72:
1. EVAP canister
2. From fuel tank
3. Evaporative Emission (EVAP) canister purge regulator valve
4. Check valve for EVAP canister. Between EVAP canister and intake manifold before turbocharger. Installation position (light/dark side): Arrow points in direction of flow.
5. Air cleaner
6. Turbocharger
7. Combination valve for secondary air injection (AIR)
8. Fuel pressure regulator
9. To power brake booster
10. Check valve-Installation position (light/dark side): Arrow points in direction of flow.
11. Vacuum booster
12. To Leak Detection Pump (LDP)
13. Vacuum reservoir
14. Distributor piece
15. Check valve-Installation position (light/dark side): Arrow points in direction of flow.
16. Secondary Air Injection (AIR) solenoid valve
17. Crankcase vent
18. Check valve-Installation position (light/dark side): Arrow points in direction of flow.
19. To tank Leak Detection Pump (LDP)
20. Check valve-Installation position (light/dark side): Arrow points in direction of flow.
21. Charge air cooler
22. Throttle valve control module
23. Recirculating valve for turbocharger
24. Intake manifold
25. Pressure unit for boost pressure regulation
26. Wastegate bypass regulator valve
27. Mechanical recirculation valve
28. Pressure control valve for crankcase ventilation
29. Secondary Air Injection (AIR) pump motor
Fig. VW Passat 1.9L Vacuum Diagram
Key List for gnam 93224vwg73:
1. Connecting pipe for charge air cooler/intake manifold
2. Vacuum connection for A/C system
3. Vacuum connection for brake servo
4. Vacuum connection for boost pressure control
5. Exhauster
6. Breather pipe for boost pressure control
7. Breather pipe on air cleaner
8. EGR valve
9. EGR vacuum regulator solenoid valve
Fig. VW Passat 2.8L Vacuum connections (top view)
Key List for gnam 93224vwg74:
1. To vacuum setting element for intake manifold change over
2. To combination valves
3. Secondary Air Injection (AIR) solenoid valve (N112)
4. To Secondary Air Injection (AIR) solenoid valve
5. To T-piece on intake manifold
6. Check valve
7. Intake manifold change over valve
8. To vacuum reservoir in left wheel well
9. From T-piece on intake manifold
10. Fuel pressure regulator
Fig. VW Passat 2.8L Vacuum connections (rear view)
Key List for gnam 93224vwg75:
1. Fuel pressure regulator
2. To crankcase breather valve
3. Vacuum booster
4. T-piece
5. Check valve
6. Intake air scoop
7. Crankcase breather valve
Fig. VW Passat 1.8L EVAP system layout schematic
Key List for gnam 93224vwg76:
1. Fuel filler cap
2. Fuel tank
3. Fuel delivery unit
4. Leak Detection Pump (LDP). In rear right wheel housing under the wheel housing liner
5. Air cleaner for LDP
6. Vacuum reservoir. Under the front left wheel housing liner
7. Check valve
8. Throttle valve control module
9. Fuel pressure regulator
10. Fuel rail with injectors
11. EVAP canister purge regulator valve 1
12. Fuel filter
13. EVAP Canister. In spare wheel well on vehicle floor
Fig. VW Passat 2.0L engine vacuum hose connections
Fig. VW Passat 2.0L vacuum hose schematic
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