Checking fuel pressure, vehicles with engine codes CWVA, CWVB, CHYA, CHYB — VW

🧭 Before you start

Pull off the supply line at the engine, connect the pressure tester with its two hoses, close the drain tap and open both shut-off taps, then build pressure with final control diagnosis and read the gauge. If out of range, repeat the test ahead of the fuel filter and then at the fuel delivery unit under the rear seat. Check lines for kinks, blockage and leaks along the way, and renew the filter or fuel delivery unit as indicated.

Fits: VW Polo 6C (2014–2017); platform code 614

• Special tools named: VAS 6550/2
• Renewed: fuel filter, fuel delivery unit

Don't miss

• The fuel line is under pressure; wear eye protection and wrap a cloth around the connection before loosening.
• Pull on each plug-in connector after fitting to confirm it is secured.
• Drain tap C closed, shut-off taps A and B open before building pressure.
• A defective pressure limiting valve in the fuel filter means renewing the whole fuel filter.

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

🔧 Engine codes this applies to

📐 36 workshop diagrams for CHYA

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

📋 Procedure

1. Observe safety precautions .
2. Observe rules for cleanliness .
3. Pull off supply line (metal connector) (1). Separate plug-in connectors .
4. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Collect escaping fuel with a cleaning cloth.
5. Connect pressure testerVAS 6550 to fuel supply line with adapterVAS 6550/1 and VAS 6550/2.

6. Connect hoseVAS 6550/1 to fuel supply line leading to engine.
7. Connect hoseVAS 6550/2 to connection (B) of pressure testerVAS 6550.
8. Use hoseVAS 6550/2 to connect fuel line leading to fuel tank with pressure testerVAS 6550.
9. Ensure plug-in connectors are secured properly by pulling.
10. Ensure that drain tap (C) on pressure testerVAS 6550(1) is closed.
11. Shut-off taps (A) and (B) on pressure testerVAS 6550(1) must be open.
12. Connect vehicle diagnostic tester.
13. Press following buttons on display one after the other: [Note: The fuel pump is now actuated to build up fuel pressure.]
14. Read off fuel pressure on pressure gauge.
15. Check return line between fuel filter and fuel pump for kinks and blockages.
16. Pressure limiting valve in fuel filter is defective.
17. Renew fuel filter.
18. Check fuel pressure ahead of fuel filter. Adopt procedure as follows to do this:
19. Pull fuel supply line (arrow) off fuel filter. Separate plug-in connectors .
20. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Collect escaping fuel with a cleaning cloth.
21. Connect pressure testerVAS 6550 between fuel filter and fuel supply line with adapterVAS 6550/1 and VAS 6550/2.
22. Connect hoseVAS 6550/1 to fuel supply line leading to fuel tank.
23. Connect hoseVAS 6550/2 to connection (A) of pressure testerVAS 6550.
24. Use hoseVAS 6550/2 to connect fuel filter to pressure testerVAS 6550.
25. Ensure plug-in connectors are secured properly by pulling.
26. Ensure that drain tap (C) on pressure testerVAS 6550(1) is closed.
27. Shut-off taps (A) and (B) on pressure testerVAS 6550(1) must be open.
28. Repeat Final control diagnosis to build up fuel pressure.
29. Check fuel lines for possible restrictions (kinks) or blockages.
30. Check fuel line for leaks and damage.
31. If fuel filter is soiled, renew it .
32. If pressure limiting valve in fuel filter is defective, renew fuel filter .
33. Proceed as follows to check fuel pressure at fuel delivery unit:
34. Fold up bench seat General body repairs, interior72Rear seats; Removing and installing bench seat/individual seats.
35. Unclip cover (1) at retaining tabs (arrows) using removal wedge3409.
36. Pull fuel lines (2) off fuel delivery unit. Separate plug-in connectors .
37. ⚠ The fuel line is under pressure.Risk of injury to eyes and skin from fuel.Wear eye protection and protective clothing to avoid eye injuries and skin contact. Before loosening hose connections, wrap a cloth around the connection. Then release pressure by carefully opening the connection point. — Connect pressure testerVAS 6550 to fuel delivery unit (1).
38. Connect hoseVAS 6550/1 to fuel supply line (2) leading to engine.
39. Connect hoseVAS 6550/2 to connection (A) of pressure testerVAS 6550.
40. Connect fuel delivery unit (1) to pressure testerVAS 6550 using hoseVAS 6550/2.
41. Ensure plug-in connectors are secured properly by pulling.
42. Ensure that drain tap (C) on pressure testerVAS 6550(1) is closed.
43. Shut-off taps (A) and (B) on pressure testerVAS 6550(1) must be open.
44. Repeat Final control diagnosis to build up fuel pressure.
45. Check fuel lines for possible restrictions (kinks) or blockages.
46. Check fuel line for leaks and damage.
47. Remove fuel delivery unit and check for contamination.
48. Check that all hose connections (arrows) are connected.
49. Check fuel lines for possible restrictions (kinks) or blockages.
50. Check fuel lines for leaks and damage.
51. Fuel pump is defective, renew fuel delivery unit .

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