Check fuel system for leaks (engine codes CBFA, CCTA, CCTB) — VW

🧭 Before you start

Fits: VW Passat CC (357, 2008–2012), VW Passat B6 (3C, 2005–2010), VW Tiguan I (5N, 2007–2016)

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• Now pressure must be maintained for at least 2 minutes. Check tester if pressure is not maintained.
• Connect adapter hoseKLI 9210/55-1 to breather line (A). (colour marking: white)
• 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. Now pressure must be maintained for at least 2 minutes. Check tester if pressure is not maintained.
9. Connect adapter hoseKLI 9210/55-1 to breather line (A). (colour marking: white)
10. Connect measuring hose (G) from fuel system testerKLI 9210 to adapter hoseKLI 9210/55-1.
11. Set valve (D) to "“Hold”".
12. Connect vehicle diagnostic tester to vehicle.
13. Start engine and run at idling speed.
14. On vehicle diagnostic tester, select operating mode Guided functions.
15. Select guided function "“Checking tank ventilation system for leaks”".
16. Initiate test.
17. Observe pressure gaugeKLI 9210 while test is running.
18. Switch off ignition and perform a pressure retention test . If no pressure drop can be detected: Check vacuum supply of fuel system diagnostic pump V144.
19. Clamp off hose to activated charcoal filter solenoid valve 1N80 using a hose clip (arrow).
20. Repeat check. If the minimum pressure is reached now, renew activated charcoal filter solenoid valve 1N80.
21. Leak in fuel system: Perform "“leak detection in fuel system”".
22. Observe pressure gauge:
23. If the pressure does not drop again, renew activated charcoal filter solenoid valve 1N80.
24. Set valve (D) to "“Test”". Set the available pressure to 10 in. H2O (25 mbar).
25. 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.]
26. Once pressure has stabilised, set valve (D) to "“Hold”".
27. 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).
28. Repeat pressure test by setting valve (D) again to "“Test”".
29. Observe pressure gauge and flow meter. When the throughput quantity decreases and the pressure increases to 10 in. H2O (25 mbar), the fuel system is filled.
30. Once pressure has stabilised, set valve (D) to "“Hold”".
31. If the pressure does not drop again, renew activated charcoal filter solenoid valve 1N80.

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