Fuel Pressure Test

Fuel Pressure Test

Special tools, testers and auxiliary items required

• Multimeter.

• fuel line adapter set (V.A.G. 1318/17A). These tools may be substituted with an equivalent aftermarket tool and are also available for rental or purchase through Volkswagen.

• In line Fuel pressure gauge with shutoff. (high pressure).

Test conditions

• Battery voltage 12.5 V

• Function and voltage supply for the Fuel Pump is OK.

• Fuel tank at least 1/4 filled.

• Ignition switched OFF.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check


Fuel system is under pressure! Before opening the system, place rags around the connection area. Then release the pressure by carefully loosening the connection.

Start diagnosis

- Disconnect fuel supply line - 2 - at the supply location and catch any fuel coming out with a shop towel





• Pull circlip upward to unlock fuel line

- Install a fuel pressure gauge with appropriate adapters.

- Open shut off valve on fuel gauge.

- Switch ignition ON and OFF repeatedly until fuel pressure gauge stops increasing pressure.

- Read fuel pressure on the gauge.

- Turn the ignition switch OFF

• Specified value: 3.5 to 5 bar

If specification is exceeded:

- Check the fuel line between the fuel delivery unit and the supply line in the engine compartment for bends and blockages

If no malfunction in fuel return line is found:

• The pressure relief valve and the fuel filter are integrated in the fuel level sensor 2 G169 with the suction jet pump and cannot be replaced individually.

- If the pressure relieve valve in the fuel filter is defective, replace fuel level sensor 2, G169 and the suction jet pump.

If the specified value was Not obtained (low pressure) :

- Fuel Pump is faulty, replace Fuel Delivery Unit (fuel pump). Refer to the repair information.

Final procedures

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

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.