Overdrive Range, Third Gear - Torque Converter Clutch Not Applied (L4 Hybrid): Notes
WARNING: This page is about a different car, the 2007 Saturn Vue. 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 energized the 2-3 shift solenoid valve in order to shift the transmission into Third gear. The manual valve remains in the Overdrive (D) position, and line pressure continues to feed the drive and the PRND4 fluid circuits.
Under certain conditions the hybrid vehicles engine will shut off and the electric auxiliary transmission fluid pump will start running to keep the transmission pressurized and ready for the engine restart. This engine off condition is a fuel economy feature and the L4 hybrid transmission's electric auxiliary fluid pump is an enabling component.