Fuel Pressure, Checking (AEG)

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Volkswagen > A4 > Procedures > Fuel Pressure, Checking > AEG

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Fuel Pressure, Checking

Special tools, testers and auxiliary items required

• High pressure fuel gauge

• Remove the fuel supply line - 2 - and catch leaking fuel using a rag.

• Install a High pressure fuel gauge in place of the fuel supply line.
• Open the shut-off valve of the High pressure fuel gauge.
• Switch the ignition on and off until the fuel pressure on no longer rises.
• Check the indicated fuel pressure on the High pressure fuel gauge.
• Specified value: 3.5 to 5.0 bar.
• If the fuel pressure is OK, check the residual pressure. Refer to = > Residual Pressure, Checking.
• If specified value is obtained:
• Check the return line between the fuel filter and the fuel pump for kinks and blockage.
• If no malfunction is found in the return line between the fuel filter and the fuel pump:
• The pressure relief valve in the fuel filter is malfunctioning, replace the fuel filter. Refer to = > Engine Mechanical, Fuel Injection and Ignition - Repair Group 20 .
• If specified value is not obtained:
• Check the fuel pressure in front of the fuel filter.

• Connect a High pressure fuel gauge between the fuel filter and the fuel supply line.
• Open the shut-off valve of the High pressure fuel gauge.
• Start the engine and let it run at idle.

• Slowly close the shut-off valve of the High pressure fuel gauge. Pressure must increase to min. 6.0 bar. If 6 bar is reached, open shut-off valve again immediately!
• If the fuel pressure increases:
• The pressure relief valve in the fuel filter malfunctioning, replace the fuel filter. Refer to = > Engine Mechanical, Fuel Injection and Ignition - Repair Group 20.
• If the fuel pressure does not increase:
• Replace the fuel pump. Refer to = > Engine Mechanical, Fuel Injection and Ignition - Repair Group 20.

  Final Procedures

• After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

End of diagnosis.

Source: 2.0 Liter 4-Cyl. 2V Generic Scan Tool, Engine Code(s): AEG > 20 - Fuel Supply