Fuel Pressure Sensor (G247)

Fuel Pressure Sensor (G247)

Special tools, testers and auxiliary items required

• Socket 27 mm (T40218) or a commercially available 27 mm socket

• Torque wrench

• The fuel pressure sensor - 1 - measures the current fuel pressure in the high pressure system and delivers a voltage signal to the Engine Control Module (ECM) (J623).






• If the malfunctions, the pressure is controlled via an ECM characteristic map (maximum engine speed is limited to emergency operation mode).

• The fuel pressure sensor has a biting edge as a seal.

Removing


• Follow the guidelines for a clean working environment when working on the fuel system. Refer to => [ Fuel System ] Fuel System.

• Always follow these rules before and during work.

- Remove engine cover. Refer to => [ Engine Cover ] Service and Repair.

- Remove the noise insulation from the cylinder head cover.

- Before removing, clean the threaded area around the fuel pressure sensor using a commercially available detergent. Dirt must not enter the hole.

• Clean carefully, cleaner must not enter the connector.

- Dry the fuel pressure sensor.

- Disconnect the electrical connector from the Mass Airflow (MAF) sensor (G247).






- Remove the fuel pressure sensor using (T40218).

• Do not use an open-end wrench for opening or tightening.

- Suction any dirt out of the hole in the fuel rail, the threads and the sealing surface. Do not use mechanical tools.

• Seal the hole in the fuel rail immediately with a suitable plug to prevent dirt from entering.

Installing

• The fuel pressure sensor has a biting edge instead of a sealing ring.

• Check for damage to the fuel pressure sensor sealing surfaces and threads. If the fuel pressure sensor is OK, it is possible to re-use it.

• Check the sealing surface on the fuel rail hole.

• Coat the fuel pressure regulator valve (N276) threads and biting edge with diesel fuel.

- Tighten the fuel pressure sensor by hand.

- Tighten the fuel pressure sensor to the specification.

• Tightening specifications, refer to => [ Fuel System Overview ] Fuel System Overview, Diesel

After installing the fuel pressure sensor, let the engine run for a few minutes to bleed the fuel system and then switch the engine off.

• The high pressure connections must "not" be opened; the fuel system bleeds itself.

- Check the Diagnostic Trouble Code (DTC) memory and erase it if necessary.

- Turn off ignition.

- Carefully check the entire fuel system for leaks.

If there are leaks even though the correct tightening specification was used, replace the affected component.

- Perform a road test where the accelerator pedal is pressed all the way down at least one time. Then check the high pressure area again for leaks.

• If there is still air in the fuel system, the engine may switch to emergency mode during the road test. Turn off the engine and erase the DTC memory. Then continue the road test.

- After the road test, check the DTC memory again.