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Fuel Pressure Sensor – find it and fix it!

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Fuel Pressure Sensors –

what is it, where to find it, how to fix it if it goes wrong.

The fuel pressure sensor is a crucial part of the modern common rail diesel system.     The fuel pressure sensor sends information to the engine management unit informing it of the present pressure in the common rail reservoir.
The fuel pressure sensor is probably the weakest component in the electronic control loop. It has to do a lot of work and is prone to failure.

What are the symptoms of fuel pressure sensor failure?

Cutting out.
Failing to start
Running in limp/ get home mode
Erratic running
Engine will run when sensor is dis-connected but will not rev
Engine runs but lacks power

Are all fuel pressure sensors the same?

No there are quite a considerable few differences. There are different makes e.g. Bosch, Siemens/Delphi and Denso.
Different types of Bosch sensors
Mercedes and BMW versus other vehicles
There are differences in the Bosch types fitted to Mercedes and BMW on the one hand and the bulk of other diesel vehicles. Mercedes and BMW Bosch sensors have a different plug design to other sensors fitted to vehicles like Peugeot, Renault and Iveco for example.

Siemens and Delphi
There are a considerable number of variations in the types of sensors fitted on vehicles running the Delphi and Siemens systems.
On the one hand the sensors can have a different pressure rating and on the other hand they can have a different plug configuration. By this I mean the male plug on the vehicle’s wiring loom is specific to the type of sensor fitted. Subtle differences on the male plug have to coincide with the same configuration on the female plug which is part of the sensor.

Denso sensors are fitted to a wide variety of vehicles particularly those originating from companies like Nissan, Toyota and Mitsubishi. They are difficult to source and at time of writing the price from main dealers has tended to be high. Like the sensors already discussed plug configuration does vary from one type to another. In other words the sensor can look identical to another but cannot be used because the plug is different.

Can fuel pressure sensors be repaired?

The typical fuel pressure sensor is a sealed and integrated unit so it cannot be dismantled. In a word they cannot be repaired. Replacement is necessary. Please view   for more information. Contact person Andy Hewing

Where will I locate the fuel pressure on my vehicle?

The fuel pressure sensor is usually located on the end of the common rail fuel reservoir. It is screwed into the rail in a conventional way and is easy to remove and replace. Unfortunately the rail is located in many different places on the many different vehicles. Sometimes the rail is at the front of the engine, sometimes behind. Follow the fuel pipes back from the injectors to locate the position of the common rail fuel reservoir.

Is the fuel pressure regulator different to the fuel pressure sensor?
Yes the sensor is different to the regulator. Some vehicles are fitted with a regulator on the rail. Usually at the opposite end of the rail to the sensor. One easy way to tell them apart is sensor is 3 pins, regulator is 2 pin.

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