Common Rail SCV

An essential part of the common rail system, Suction Control Valves (SCVs) are vital for maintaining the right pressure in the fuel system to meet the required low emissions levels and high power output.

Common Rail SCV

How common rail SCVs work

The common rail system is essential for delivering fuel under the right pressure to the rest of the engine. Keeping the fuel pressure level correct and accurate is vital for the engine to perform the combustion process efficiently. Efficient combustion ensures the reliable performance of the engine, helps to reduce carbon emissions and maximizes fuel consumption.

SCVs control the amount of fuel that is pumped through the common rail system, therefore helping to maintain consistent fuel pressure. This ensures that the common rail injectors can deliver the right amount of fuel under the correct pressure to the combustion chamber, optimizing combustion performance and increasing overall engine efficiency.

HP2 type pump with red green SC Vs visible

Features and benefits

  • Part of DENSO’s pioneering common rail system.
  • Ensures consistent fuel pressure levels.
  • OE quality standard component.
  • Easy-to-use part numbering system.
Consistent fuel pressure
SCVs are an essential part of the common rail system due to their control over fuel supply to reach a consistent pressure. Without SCVs, the system couldn’t function accurately.
High-quality parts
Made to OE manufacturer’s standards, each part of DENSO’s common rail system is high-quality and meets the applications of a range of vehicle types.
Wide product range
With an easy-to-use product numbering system, it’s easy to find the right SCV for your application, whether it’s an application with a HP2, HP3 or HP4 High Pressure pump system.

Types and characteristics

Although DENSO common rail components suit a range of applications, they also maintain a consistent level of quality, meeting OE manufacturer’s standards.

Common Rail SCV types

For HP2 pump system

Because this high-pressure pump has two pumping mechanisms, it also has two SCVs.

These on/off solenoid valves use a green or red connector to identify the two pumping systems, which is important for pump timing.

These two SCVs are sold as one kit.

SC Vs for HP2 pump
For HP3 and HP4 pump system

Operation of the SCV is same for HP3 and HP4 pump systems.

For these two pump systems, depending on application, DENSO uses two different types of SCV. Both of them are linear solenoid valves and operate in the opposite way to each other.

SCV for HP3 HP4 pump
Normally closed SCV

This SCV is fully closed when the solenoid is not energized. Depending on demand, the SCV will move to the right opening position.

Normally open SCV

This SCV is fully open when the solenoid is not energized. Depending on demand, the SCV will move to the right opening position.


The unique design of DENSO SCVs ensures that fuel pressure remains consistent, enabling the common rail system to function reliably and accurately.

Catalogues and marketing materials

To find out more about Common Rail SCV browse the Downloads Area section. Click here.


Ensuring that SCVs are installed accurately and maintained properly will keep the common rail system performing efficiently.


  • Install one new O-ring.

  • Install two guide pins in the mounting holes and install the new gaskets.

  • Apply engine oil on small O-ring.

  • Install the SCV by carefully pushing it into the housing (to avoid O-ring damage). When the SCV is in position, remove the guide pins.

  • Fit the bolts and tighten them to 6.9-10.8Nm.

  • Once the installation is complete, connect the vehicle to the DENSO diagnostic tester DST-PC/DENSO C and perform available routines for pump testing at the required engine conditions. Ensure that there are no system leaks and no Diagnostic Trouble Codes.