How to test suction control valve?
Home » car repair tips

How to test suction control valve?

Suction Control Valve (SCV) is one of the important actuators in the common rail system. SCV is usually installed in the supply pump (high-pressure fuel pump). The function of the SCV is to control fuel pressure inside common rail engines. It allows only the required amount of fuel to be pumped through the system.

The SCV is directly connected to the engine Engine Control Unit (ECU). Therefore, if the SCV has a problem or any symptoms of the damage, the ECU will order the check engine warning lamp to turn on so the driver can see it.

How to test suction control valve - scv

To determine the SCV damage, we need a scanner that is compatible with the car. When the SCV is damaged, the Diagnostic Trouble Codes (DTC's) will appear. For example, P0089 (Suction Control Valve stuck), P0628 (Suction Control Valve open), P0629 (Suction Control Valve battery short), or P1275 (Supply pump exchange). Read: Common Rail Diesel Starting Problems

This article will share information about checking the SCV (Suction Control Valve) specifically for Mitsubishi Montero Sport and Mitsubishi Triton with 4D5 engines. Below is how to check a Mitsubishi Montero Sport SCV's



I. Measure the resistance value of the SCV


Measurement of the resistance value of the SCV aims to ensure that the coil in the SCV is in good condition, not broken or short. For accurate inspections, it's better to use a digital multitester. Here are the inspection steps.

  1. Disconnect the connector wire from the suction control valve.
  2. Turn on the digital multitester and select the selector for the resistance measurement (ohms). Don't forget to calibrate the multitester before measuring the resistance value.
  3. Measure the resistance between the no.1 and no.2 terminals on the suction control valve.
  4. The standard resistance for SCV is 2.1 ohms (at 20 degrees Celsius)
  5. If the resistance value is less or more than the standard value, then the SCV is considered defective.



II. Physical examination and movement of the SCV valve


This physical examination and movement of the SCV valve ensure that the SCV can move and work normally. Here are the inspection steps.

  1. Remove the SCV from the supply pump.
  2. Check and pay attention to the SCV body. If there are bends or dents in the body, it indicates the SCV is not good.
  3. Pay attention to the existing o-ring rubber condition and make sure the o-ring is in good shape.
  4. Check the front of the SCV where the SCV valve is located, make sure the condition does not show any wear or dirt clogging, which can cause a DTC P0089 (Suction Control Valve stuck).
  5. Attach the SCV to the connector cable.
  6. Turn the ignition switch to the ON position.
  7. A good SCV will show vibrations on the SCV body when the ignition is turned ON. Also, pay attention to the valve hole in front of the SCV. When turned ON, the valve will also appear to be moving.

Also read:

Damage to the SCV indicated based on the above examination requires replacing the SCV with a new one. But suppose the resistance value is still in standard value and appropriate. In that case, we can do SCV cleaning by opening the snap ring on the front of the valve and removing the valve along with the spring.

Pay attention to the valve wall. If there is severe wear or tear, it means that the SCV must replace. If not, try to clean and reinstall the SCV. If the results are still the same, check more carefully for other common rail system components to avoid missing part replacement estimates.

SHARE