Checking holding pressure, engine code CWVA

• Observe safety precautions → Chapter.
• Observe rules for cleanliness → Chapter.

• Pull off supply line -1-. Separate plug-in connectors → Chapter.

• Collect escaping fuel with a cleaning cloth.

• Connect fuel line from fuel tank to shut-off tap -B- of pressure tester -VAS 6550- by means of hose -VAS 6550/2-.
• Connect fuel line leading to engine -1- to shut-off tap -A- of pressure tester -VAS 6550- by means of hose -VAS 6550/1-.

Test sequence:

• Connect vehicle diagnostic tester.
• Select final control diagnosis for fuel pump in vehicle self-diagnosis program.

Note

The fuel pump is now actuated to build up fuel pressure.

• Read off fuel pressure on pressure gauge.

Specification: ≥ 4.0 bar.

• End self-diagnosis and switch off ignition.
• Observe pressure drop on pressure gauge. After 10 minutes, the pressure must not drop by more than 1.0 bar.

If pressure drops:

• Check all fuel lines for leaks and damage.

If no fault is detected:

• Ensure that drain tap -C- on pressure tester-1- is closed.
• Shut-off valves -A- and -B- on pressure tester-1- are open.
• Actuate fuel pump with final control diagnosis to build up fuel pressure.
• After pressure has built up, close shut-off valve -A- of pressure tester immediately. Lever is then at right angle to direction of flow.

If the pressure now drops (leak on fuel tank side):

Proceed as follows to check residual pressure on fuel delivery unit → Anchor.

If the pressure does not drop now (leak on engine side):

Note

If there is a leak on engine side:

• Check surfaces of fuel lines for leaks.
• Check surfaces of fuel rail and injectors for leaks → Rep. gr.24.

If no fault is found:

• Check injectors for leaks → Rep. gr.24.

Checking holding pressure on fuel delivery unit:

Golf SV:

• Remove right rear seat → General body repairs, interior; Rep. gr.72.

• Partially detach cover -1- in floor covering at parting line -arrow-.
• Do not detach cover completely from floor covering in order to ensure it is reinstalled in the correct installation position.
• Detach it just enough that the cover can be folded upwards.
• Fold up cover in -direction of arrow-.

Golf and Golf Estate:

• Remove rear bench seat → General body repairs, interior; Rep. gr.72.

Continuation for all vehicles:

• Unclip cover -1- for flange at retaining tabs -arrows-, using removal wedge -3409-.

• Unclip sealing grommet -1- downwards from cover -2-.
• Push cover -2- back along wiring harness -3-.

• Pull fuel line -1- off flange. Separate plug-in connectors → Chapter.

• Connect pressure tester -VAS 6550- to fuel delivery unit -1- by means of hose -VAS 6550/3-4-.
• Connect pressure tester -VAS 6550- to fuel line -2- by means of hose -VAS 6550/3-3-.
• Ensure plug-in connectors are secured properly by pulling.

• Ensure that drain tap -C- on pressure tester-1- is closed.
• Shut-off valves -A- and -B- on pressure tester-1- are open.
• Actuate fuel pump with final control diagnosis to build up fuel pressure.
• After pressure has built up, close shut-off tap -B- of pressure tester immediately. Lever is then at right angle to direction of flow.
• Repeat holding pressure check → Anchor.

If pressure no longer drops:

• Check fuel line for leaks.

If the pressure drops again:

• Open fuel delivery unit -1- → Chapter.
• Check that all hose connections -arrows- are connected.
• Check fuel lines for leaks and damage.

If no fault is found:

• Pressure retention valve in fuel delivery unit is defective; renew fuel delivery unit → Chapter.