Checking fuel system pressurisation pump G6 - A5 from model year 2012 onwards, A4 with 4-cyl. and 6-cyl. engines from model year 2013 onwards, RS 5 from model year 2012 onwards, RS 4 — AUDI

🧭 Before you start

Fits: Audi A5 Cabriolet (8F), Audi A5 (8T, 2007–2016), Audi A4 B8 (8K, 2007–2015)

• Opens: fuel

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• Disregard (item 3).
• Illustration shows measuring equipment connected on a 4-cyl. engine as an example.
• Risk of fuel escaping.Cut-off valve (C) must be closed.The lever should point perpendicular to direction of flow. — Connect vehicle diagnostic tester.
• From this point on, do not turn adjuster screw (1).
• To find the precise cause of the fault, a pressure test must be performed on the fuel supply line as described below.

🔧 Engine codes this applies to

📐 37 workshop diagrams for CABA

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Observe test conditions (see the separate procedure).
2. Release and open tank flap.
3. Remove filler cap (2) for fuel filler neck (1). [Note: Disregard (item 3).]
4. ⚠ Risk of injury - fuel system operates under high pressure. To reduce the pressure in the fuel system, wrap a clean cloth around the connection and carefully loosen the connection. — Disconnect fuel line (2). Disconnecting plug-in connectors
5. Push down protective sleeve (1) and disconnect hose connector (2).

6. Connect pressure tester VAS 6550 to fuel supply line with hose VAS 6550/2.
7. Attach pressure control valve VAS 6550/4 and hold end of hose into fuel-resistant measuring container. [Note: Illustration shows measuring equipment connected on a 4-cyl. engine as an example.]
8. Switch on pressure tester VAS 6550(item 1) by pressing On/Off button.
9. Open cut-off valves (A and B). [Note: To measure the fuel delivery rate, pressure must first be built up in the fuel line; the fuel pump must then operate against this pressure during the measurement. This pressure can be built up using the pressure control valve VAS 6550/4 as follows:]
10. ⚠ Risk of fuel escaping. Cut-off valve (C) must be closed. The lever should point perpendicular to direction of flow. — Connect vehicle diagnostic tester.
11. Switch on the ignition and select the following menu options on the vehicle diagnostic tester:
12. Press Start: The fuel pump will start running.
13. Build up pressure in fuel system by turning adjuster screw (1) on pressure control valve VAS 6550/4 until correct pressure is reached.
14. From this point on, do not turn adjuster screw (1).
15. Press Stop.
16. Drain measuring container.
17. For measurement, press Start again and let fuel pump run for 15 seconds.
18. Press Stop after 15 seconds.
19. Check amount of fuel delivered in measuring container. [Note: To find the precise cause of the fault, a pressure test must be performed on the fuel supply line as described below.]
20. Switch on pressure tester VAS 6550(item 1) by pressing On/Off button.
21. Open cut-off valves (A and B).
22. ⚠ Risk of fuel escaping. Cut-off valve (C) must be closed. The lever should point perpendicular to direction of flow. — Press Start on vehicle diagnostic tester display to start the fuel pump.
23. When fuel emerging is free of bubbles, close cut-off valve (B) to allow fuel pressure to build up.
24. Read fuel pressure off pressure tester VAS 6550:
25. Press Stop.
26. Check system for leaks and check residual pressure by watching drop in pressure on pressure tester VAS 6550: [Note: Before removing the pressure tester (1), release the fuel pressure by opening the cut-off valves (B, C) and allowing fuel to drain off into a measuring container.]
27. Detach pressure tester VAS 6550 together with connection leads.
28. Connect fuel supply line, making sure it engages audibly.
29. Press fuel supply line in again and then pull to check that plug-in connector is correctly engaged.

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