Fuel Pressure Sensor: Testing and Inspection

Fuel Pressure Sensor, Checking

• Always follow the safety precautions when reducing the high side fuel pressure. Refer to => [ Safety Precautions ] Safety Precautions.

• Follow the guidelines for cleanliness. Refer to => [ Clean Working Conditions ] Clean Working Conditions.

Special tools, testers and auxiliary items required

• Assembly Tool (T10118)

• 27 mm Crows Foot Wrench, 3/8" Drive

• Pressure Sensor Tester (VAS 6394)

• Test Instrument Adapter/DSO (3-pin) (VAS 5570)

• Vehicle Diagnostic Tester

Procedure

The fuel lines are under pressure.

Danger of personal injury to eyes and skin.

Wear protective eyewear and protective clothing in order to avoid injury and contact with the skin. Wrap a cloth around the connection before removing a fuel hose. Open the connection carefully and release the pressure.

- Disconnect the fuel pressure sensor - A - connector and remove the sensor with a crows foot wrench.






- Remove the locking bolt - 2 - and install the fuel pressure sensor into the pressure sensor tester (VAS 6394/1). Tightening specification: 22 Nm.






- Coat the adapter (VAS 6294/3) sealing point with clean engine oil and install it in the fuel rail - arrow -. Tightening specifications: 22 Nm.






- Connect the pressure sensor tester (VAS 6394/1) pressure line to the adapter (VAS 6394/3) - arrow -.






- Connect the fuel pressure sensor and the fuel pressure sensor connector using the test instrument adapter/DSO (3-pin) (VAS 5570).

- Press the button - A - once briefly to turn on the pressure sensor tester (VAS 6394/1).






• Pressing the button - A - for 2 seconds will turn on the illumination for 20 seconds.

• Set the pressure sensor tester (VAS 6394/1) back to "0" bar if it is not displaying "0" already. Refer to the operating instructions.

- Connect the vehicle diagnostic tester to the diagnostic connector.

- Turn on the ignition.

- Select "Guided Function" Check Fuel Pressure Sensor G247.

- Start the engine.

- Compare the pressure displayed on pressure sensor tester (VAS 6394/1) with the actual value displayed on the vehicle diagnostic tester.

• The pressures may have a maximum difference of 5 bar.

- If the difference is greater than 5 bar, replace the fuel pressure sensor.

The pressure sensor tester (VAS 6394) is under high fuel pressure. Disconnect the connector from the fuel pressure sensor while the engine is still running. This reduces the pressure to approximately 6 bar. Turn off the ignition and place a cloth over the fuel pressure sensor. Loosen the fuel pressure sensor carefully and release any remaining pressure.

- Repeat the test with the new fuel pressure sensor and compare both values.

If the measured value do not match again:

- Check the wiring.