Decreased Pressure/Flow Condition
WARNING: This page is about a different car, the 2008 GMC Yukon and 2008 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
Oil from the oil pan sump is drawn into the pump inlet (1). The rotor and vanes of the pump are rotated in a clockwise direction pressurizing the oil (4). Pressurized oil exits at the pump outlet (5) and continues to the engine oil galleries. In this mode of operation, the hydraulic force of the oil pressurizes the cavity (4) on the outer area of the slide (3). When the hydraulic force increases sufficiently, it overcomes the spring (2) force and pivots the slide counterclockwise. As the slide pivots counterclockwise, the pump outlet pressure and displacement decreases, which in turn reduces the required drive torque.