Overdrive Range, Second Gear (W/O Electronic Range Select Mode): Notes
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.
As vehicle speed increases and operating conditions become appropriate, the PCM de-energizes the 1-2 shift solenoid valve in order to shift the transmission into Second gear. The manual valve remains in the Overdrive (D) position and line pressure is routed into the drive and PRND4 fluid circuits.