Golf Mk4
| Engine codes ARZ, AQA, AUM and AUQ |
| 1 - | Breather line |
| q | From gravity valve on fuel tank → Item. |
| 2 - | Active charcoal filter |
| q | With active charcoal filter solenoid valve 1 -N80-. |
| 3 - | Turbocharger |
| 4 - | Non-return valve |
| q | For active charcoal filter system. |
| 5 - | Pressure actuator |
| q | For charge pressure regulating valve. |
| 6 - | Overrun shut-off valve |
| 7 - | Charge pressure control solenoid valve -N75- |
| q | The valve will be activated from the engine control unit (pulsed). |
| 8 - | Brake servo |
| 9 - | Non-return valve |
| q | For brake servo. |
| 10 - | Air cleaner with air mass meter -G70- |
| 11 - | Crankcase breather pressure regulating valve |
| 12 - | Combination valve |
| q | Engine codes ARZ, AUM, AUQ. |
| q | For secondary air system. |
| q | Checking → Chapter. |
| 13 - | Fuel pressure regulator |
| 14 - | Non-return valve |
| 15 - | Turbocharger divert air valve -N249- |
| 16 - | Secondary air inlet valve -N112- |
| q | Engine codes ARZ, AUM, AUQ. |
| 17 - | Crankcase breather |
| 18 - | Non-return valve |
| q | For active charcoal filter system. |
| 19 - | Charge pressure sender -G31- / charge air cooler |
| 20 - | Secondary air pump motor -V101- |
| q | Engine codes ARZ, AUM, AUQ. |
| 21 - | Vacuum reservoir |
