Reduction Valve
WARNING: This page is about a different car, the 2005 Suzuki Reno and 2005 Suzuki Forenza. However, it is still accessible from the selected car via links, so may be relevant.
The reduction valve reduces the line pressure with which the downstream solenoid valves and pressure control solenoid valves (EDS) are supplied. This makes it possible to use smaller solenoid valves. The line pressure comes from the oil pump and flows to the reduction valve. The inlet port to the reduction valve will be blocked and line pressure will be maintained at the appropriate level.