Circuit/System Description (Hybrid)

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: MY 2008 and 2009 Transmission models 9BAJ and 9BBJ have a normally open pressure switch A.
MY 2009 Transmission models 9CCJ and 9DAJ have a normally closed pressure switch A.

The automatic transmission fluid pressure (TFP) manual valve position switch consists of four pressure switches. Two of the switches are normally-open, and determine gear range selection. The third switch is normally-closed, and detects torque converter clutch (TCC) release fluid pressure. A fourth switch may be normally open or normally closed, depending on the transmission model, and is used to determine if the transmission has line pressure for Hybrid operation. The TFP manual valve position switch also contains the automatic transmission fluid temperature (TFT) sensor. These components are combined into one unit that is attached to the control valve body.

The transmission control module (TCM) provides a reference voltage on the two range signal circuits. By grounding one or more of switches B and C with fluid pressure from the manual shift valve, the TCM detects the selected gear range. Switch A indicates to the engine control module (ECM) if there is line pressure, from either the transmission or the auxiliary transmission pump, which allows hybrid operation.