Fuel Pressure Sensor/Switch: Service and Repair

Fuel Pressure Sensor (G247)

The fuel pressure sensor is located inside the left rail (cylinder bank 2) and measures the current fuel pressure in the high pressure system and sends a voltage signal to the Engine Control Module (ECM) (J623).






Removing

Follow the guidelines for a clean working environment when working on the fuel system. Refer to => [ Clean Working Conditions ] Clean Working Conditions.

Always follow these instructions before and during work.

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

- 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.

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

- Dry the fuel pressure sensor.

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

- Remove the fuel pressure sensor.

- Suction any dirt out of the hole, 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, is it possible to re-use it.

• Check the sealing surface on the fuel rail hole.

• Coat the fuel pressure sensor thread and biting edge with diesel fuel.

- Tighten the fuel pressure sensor by hand.

- Tighten the fuel pressure sensor to the specification.

• Tightening specifications: fuel system, assembly overview, refer to => [ Fuel System Overview ] Fuel System Overview

Fuel System, Bleeding and Performing a Leak Test

- After installing, let the engine run at a moderate speed for a few minutes and then stop it.

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

- Check Diagnostic Trouble Code (DTC) memory and erase, 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.