If simulation function of M-MDS is used:

Turn the ignition switch to the ON position. (Engine off)
Turn the variable swirl solenoid valve from off to on using the IMRC PID and verify that the operation sound of the solenoid valve is heard.
- If the operation sound is not heard, replace the variable swirl solenoid valve.
- If the operation sound is not heard, inspect the following:
  - Vacuum hose and vacuum chamber for looseness or damage
  - Shutter valve actuator
  - Check valve is stuck open or closed
  - Shutter valve cannot move smoothly