Common Rail Pressure Regulator

A Common Rail Pressure Regulator is a type of solenoid valve. UK Diesel Parts Common Rail Pressure Regulator Valve also know in the industry as Diesel Regulator Valve (DRV) or Fuel Pressure Regulator (FPR) are fixed to the common rail high-pressure pumps or to the common rail in majority of modern diesel cars.

The function of the Common Rail Pressure Regulator is to keep the pressure in the rail at a constant level. Common rail pressure sensor indicators the pressure required in the fuel rail to the ECU.

The ECU then switches the regulator to open or close. The rail encompasses a pressurised quantity of diesel fuel ready for the injectors to use, when the pressure in the rail drops the sensor signals this to the ECU and pressure is replenished.

What type of regulator is fitted to your vehicle?

Some Common Rail Pressure Regulator screw into the common rail.

They are easy to remove when the engine is switched off. Simply remove the electric male connecting plug and unscrew in a conventional way.

Other regulators are held in place by two or three bolts. These are often found in place on the high pressure fuel pump.

DRV’s can look different. Look out for different internal endings, different female plug fittings and different mounting bolts. (see pictures 1 and 2)

Picture 1 Picture 2

Common symptoms of regulator failure are:

  • Difficult to start
  • Cutting out
  • Rough Running

Fault codes often seen when diagnosing a common rail pressure regulator failure are:

  • P1271
  • P1278
  • P1272

If the regulator is faulty you will get an error code indicating this when you run a diagnostic check on the engine.

The fuel pressure regulator is simple to replace and you will not need to code to the engine.

You will need to remove the current fault codes in the ECU memory.

You must check the numbers on the regulator and replacement with either the exact number or one of the cross reference numbers correspond to the original.

Bosch numbers are 10 digit starting 0281 002 – – –

VDO Siemens also use numbers like X39-800-300-***Z, A2C******** or 55PP06-03

The number is usually located on the back of the regulator. (see picture 3)

Picture 3


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