Fuel Pressure Sensor/Switch: Service and Repair

Fuel Pressure Sensor

Function

The fuel pressure sensor (rail pressure sensor) is located in the rail element (high pressure reservoir). It measures the current fuel pressure in the high pressure system and delivers a voltage signal to the ECM.

If the fuel pressure sensor malfunctions, the pressure is controlled via an ECM characteristic map (maximum engine speed is limited to approximately 3000 RPM in emergency operation mode).

Special tools, testers and auxiliary items required

• Torque Wrench (V.A.G 1332)

CAUTION!
• Follow the safety precautions when working on the diesel direct injection system. Refer to --> [ Safety Precautions ] Safety Precautions.

• Observe rules for cleanliness. Refer to --> [ Clean Working Conditions ] Clean Working Conditions.

Always follow these instructions before and during work.

Removing

- Remove engine cover. Refer to --> [ Engine Cover ] Engine Cover.

- Before removing, clean the threaded area around the fuel pressure sensor (for example using commercially available coolant). Contamination must not enter the bore in the rail element (high pressure reservoir).

• Clean carefully, cleaner must not enter the connector.

- Dry the fuel pressure sensor.

- Disconnect connector on the fuel pressure sensor - C -.





- Remove the fuel pressure sensor.

- Extract the contamination from the rail element bore (threads and sealing surface). Do not use mechanical tools.

• Seal the rail element bore immediately with a suitable plug to prevent contaminants from entering.

Installing

• Check the fuel pressure sensor sealing surface and threads for damage.

• Check sealing surface on the rail element bore.

• The fuel pressure sensor threads are coated with an anti-friction coating so they must be free of oil and grease.

- First tighten the fuel pressure sensor by hand.

- Then tighten fuel pressure sensor to specification. Refer to --> [ 14 , 100 Nm ] Removal and Replacement.

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

- Check fuel system for leaks. Refer to --> [ Fuel System, Performing Leak Test ] Testing and Inspection.

- Read the ECM DTC memory again.

- Install engine cover. Refer to --> [ Engine Cover ] Engine Cover.