Variable Swirl Actuator (VSA) Deactivation

Variable Swirl Flaps and its Actuator, also known as VSA, is a system of small butterfly valves mainly fitted in diesel engines with at least two intake ports. They are installed just before one of the cylinder's intake ports, allowing it to throttle its airflow and causing air swirl in the other intake port, which is not fitted with a swirl flap. The resulting air swirl improves the air-fuel mixing process, enhancing fuel efficiency and helping to comply with emissions standards at low engine loads. However, sometimes we need to disable the VSA in the engine control unit to determine the exact cause of vehicle malfunction and eliminate other possibilities.