Checking fuel system for leaks: VW Golf V / Jetta (AUG, AWM, AWT, AXQ, …)

🧭 Before you start

Fits: VW Golf V / Jetta (1K, 2003–2009); platform code AJ5

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• Pressure must now be maintained for at least 2 minutes. Check tester if pressure is not maintained.
• Depending on the filling level of the fuel tank, this process can take up to 3 minutes.

🔧 Engine codes this applies to

📋 Procedure

1. Check on fuel system testerKLI 9210 if there is enough fluid in smoke generator.
2. Set valve (D) to "“Hold”".
3. Open nitrogen bottle (H).
4. Connect test hose (G) to self-test connection (B).
5. Set valve (D) to "“Test”".

6. Regulate pressure to 10 in. H2O (25 mbar) with pressure reducer (J).
7. Set valve (D) to "“Hold”".
8. Pressure must now be maintained for at least 2 minutes. Check tester if pressure is not maintained.
9. Note safety precautions before beginning work .
10. Observe rules for cleanliness .
11. Connect adapter hoseKLI 9210/55-1 to breather lines (A) as shown.
12. Connect measuring hose (G) from fuel system testerKLI 9210 to adapter hoseKLI9210/55-1.
13. Connect vehicle diagnostic tester(1) as follows:
14. Push diagnostic cable connector (2) onto diagnostic connection in driver footwell.
15. Start engine and run at idling speed.
16. On vehicle diagnostic tester, select operating mode Guided functions.
17. Select "“guided function”"Checking tank ventilation system for leaks.
18. Initiate test.
19. Observe pressure gauge on fuel system testerKLI 9210 while test is running.
20. Switch off ignition.
21. Carry out a pressure retention test .
22. Test vacuum supply of fuel system diagnostic pump V144.
23. Clamp off hose to activated charcoal filter solenoid valve 1N80 using a hose clip (arrow).
24. Repeat check.
25. Renew activated charcoal filter system solenoid valve 1N80.
26. Leak in fuel system: Perform "“leak detection in fuel system”".
27. Switch off ignition.
28. Observe pressure gauge:
29. Carry out a pressure retention test to localise any potential small leaks .
30. Clamp off hose to activated charcoal filter solenoid valve 1N80 using a hose clip (arrow).
31. Renew activated charcoal filter system solenoid valve 1N80.
32. Leak in fuel system: Perform "“leak detection in fuel system”".
33. Set valve (D) to "“Test”". Set the available pressure to 10 in. H2O (25 mbar).
34. Observe pressure gauge (C) and flow meter (E). When the throughput quantity decreases and the pressure increases to 10 in. H2O (25 mbar), the fuel system is filled. [Note: Depending on the filling level of the fuel tank, this process can take up to 3 minutes.]
35. Once pressure has stabilised, set valve (D) to "“Hold”".
36. First check activated charcoal filter solenoid valve 1N80 for leaks. To do this, clamp off hose to activated charcoal filter solenoid valve 1N80 using a hose clip (arrow).
37. Repeat pressure test by setting valve (D) again to "“Test”".
38. Observe pressure gauge and flow meter:
39. Once pressure has stabilised, set valve (D) to "“Hold”".
40. Renew activated charcoal filter system solenoid valve 1N80.
41. Perform "“leak detection in fuel system”".
42. Once work is complete, use vehicle diagnostic tester to perform guided functions, checking tank ventilation system for leaks.

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