Checking non-return valves of fuel pump 1V276 and fuel pump 2V277 — VW

🧭 Before you start

Remove the right sender flange cover, unplug the flange and remove its locking ring. Separate the supply line of 1V276 and connect the pressure tester, pull fuel pump relay J17 and run the pump from the remote control to about 6 bar. Close cut-off tap B and watch the gauge for 10 minutes; then repeat by building pressure again and closing tap A for the left pump. A pressure drop below 4.5 bar on either test means renewing that fuel delivery unit.

Fits: VW Phaeton (3D)

• Renewed: fuel delivery unit

Don't miss

• Mask the second adapter cable connection to prevent a short-circuit.
• Drain tap closed and cut-off taps open before pressurising.
• Pressure must stay above 4.5 bar after 10 minutes with the tap closed.
• Pull fuel pump relay J17 before running the pump from the remote control.
• A failed non-return valve means renewing the fuel delivery unit, not the valve.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

📋 Procedure

1. Pull out pins (arrows) and remove cover for right sender flange in luggage compartment floor (A).
2. Pull connectors (arrows) off sender flange.
3. Now remove locking ring from flange using fuel tank sender unit tool3087.
4. On right side, separate supply line (1) of fuel pump 1V276.
5. Connect pressure testerVAS 6550 with adapterVAS 6550/1 and adapterVAS 6550/2 to supply line of fuel pump 1V276.

6. Make sure that drain tap is closed and cut-off taps are open.
7. Pull fuel pump relay J17 from socket (1).
8. Connect remote controlV.A.G 1348/3A with adapter cable, PhaetonV.A.G 1348/3-3 to terminal 87 of fuel pump. Mask second connection of adapter cable to prevent short-circuit.
9. Connect positive terminal (1) of remote control to positive pole of battery in luggage compartment.
10. Press remote controlV.A.G 1348/3A until a pressure of approx. 6 bar is displayed on pressure gauge.
11. Watch pressure drop on pressure gauge and close cut-off tap (B). After 10 minutes, pressure must not drop below 4.5 bar.
12. Non-return valve in right fuel pump 1V276 defective, renew fuel delivery unit .
13. To do this, open cut-off tap (B) and build up fuel pressure by pressing remote controlV.A.G 1348/3A.
14. After pressure has built up, close cut-off tap (A).
15. Non-return valve in left fuel pump 2V277 defective, renew fuel delivery unit .

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