Auxiliary Line Boost Valve
WARNING: This page is about a different car, the 2010 GMC Sierra and 2010 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
PCS 5 signal fluid, at the auxiliary line boost valve, opposes auxiliary line boost valve spring force and orificed auxiliary line boost fluid pressure to regulate line or auxiliary line pressure into the auxiliary line boost circuit. Auxiliary line boost fluid is routed to the fluid pump and auxiliary fluid pump valve in order to regulate auxiliary line fluid pressure.