Removing and installing fuel pump control unit J538 - rest-of-world vehicles with front-wheel drive — AUDI

🧭 Before you start

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

• Opens: fuel
• Renewed: seal

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• Danger! Fuel may escape.The fuel tank must not be more than 1/4 full when removing the fuel pump control unit J538, otherwise a large amount of fuel will escape. — Drain fuel tank if necessary .
• 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) from flange .
• The plastic detent on the threaded ring will break off when the union nut is unscrewed - this can be disregarded.
• Renew seal and union nut.
• Take care to avoid leakage at flange.Press flange downwards firmly when tightening union nut to make sure flange does not also turn. — Tighten union nut for flange using union nut tool T40068A.

🔧 Engine codes this applies to

📋 Procedure

1. Observe safety precautions .
2. Observe rules for cleanliness .
3. ⚠ Danger! Fuel may escape.The fuel tank must not be more than 1/4 full when removing the fuel pump control unit J538, otherwise a large amount of fuel will escape. — Drain fuel tank if necessary .
4. Move passenger's seat as far to front as possible (if necessary).
5. ⚠ To prevent irreparable damage to the electronic components when disconnecting the battery:Observe notes on procedure for disconnecting the battery. — Disconnect battery Electrical system27Battery; Disconnecting and connecting battery.

6. Remove rear seat bench General body repairs, interior72Rear seats; Removing and installing seat bench/individual seats.
7. Unscrew cover for flange (arrows).
8. If fitted, unplug electrical connector (2) for metering pump for auxiliary heater on flange.
9. Unplug electrical connector (1) on flange.
10. To do so, slide catch (1) upwards (arrow A) and press release catch inwards (arrow B).
11. ⚠ 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) from flange .
12. If fitted, disconnect fuel line (1) for metering pump for auxiliary heater on flange .
13. If fitted, unplug electrical connector (2) for metering pump for auxiliary heater on flange.
14. Release retainer catches with assembly tool T10118 and unplug electrical connectors (1 and 3) on flange.
15. ⚠ 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) from flange .
16. If fitted, disconnect fuel line (1) for metering pump for auxiliary heater on flange .
17. ⚠ Danger! Fuel may escape.The fuel tank must not be more than 1/4 full when removing the flange, otherwise a large amount of fuel will escape. — Unscrew union nut using union nut tool T40068A(arrow). [Note: The plastic detent on the threaded ring will break off when the union nut is unscrewed - this can be disregarded.]
18. Cover opening of fuel tank with clean cardboard (1) to prevent dirt particles from falling into the tank.
19. Remove bolts (arrows).
20. Guide out fuel pump control unit J538(item 1) towards interior between fuel tank and underbody.
21. Unplug electrical connector and remove fuel pump control unit. [Note: Renew seal and union nut.]
22. Bring fuel pump control unit J538 into installation position and secure with bolts.
23. Slip union nut (1) over your left arm and press flange (2) firmly into installation position (arrow) with your left hand.
24. Take union nut (1) off your left arm with your right hand and at the same time keep pressing down flange (2) firmly with your left hand (arrow).
25. Position union nut (1) with your right hand in such a way that double ridge (5) on ribs aligns with lug (3) of flange (approx. "“ten o'clock position”"). This will make union nut engage immediately with beginning of thread (4) when tightening.
26. Keep pressing flange downwards firmly (arrow).
27. Turn union nut approx. 480° with your right hand until double ridge (1) is in approx. "“two o'clock position”" and at the same time keep on pressing flange downwards firmly with your left hand.
28. ⚠ Take care to avoid leakage at flange.Press flange downwards firmly when tightening union nut to make sure flange does not also turn. — Tighten union nut for flange using union nut tool T40068A.
29. Connect fuel line, making sure it engages audibly.
30. Press fuel line in again and then pull to check that plug-in connector is correctly engaged.
31. Connect electrical connectors.
32. Install cover for flange .
33. Install rear seat bench General body repairs, interior72Rear seats; Removing and installing seat bench/individual seats.
34. Connect battery and perform steps required after re-connecting battery Electrical system27Battery; Disconnecting and connecting battery.
35. Vehicles with auxiliary heater: Bleed fuel supply line leading to metering pump .

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