Pressure Control (PC) Solenoid 3 Trim
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.
The PC solenoid 3 trim is commanded OFF, allowing PCS 3 signal fluid to exhaust from the hybrid low, 1-2 clutch regulator valve; the hybrid low, 1-2 clutch boost valve; and the shift solenoid valve - mode B.