1-2/3-4 Accumulator Valve
WARNING: This page is about a different car, the 2010 Pontiac G5 and 2010 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
The accumulator valve regulates the line pressure into the 1-2/3-4 accumulator fluid circuit in order to fill the 1-2 accumulator. Torque signal fluid pressure controls this regulation. Accumulator fluid pressure is regulated to a higher pressure with greater torque signal fluid pressure.