Theory Of Operation
WARNING: This page is about a different car, the 2009 Dodge Caliber. However, it is still accessible from the selected car via links, so may be relevant.
The A/C Pressure Transducer signal is a direct input to the Totally Integrated Power Module (TIPM). The TIPM sends the Powertrain Control Module (PCM) the A/C pressure signal over the CAN C bus.