Theory Of Operation
WARNING: This page is about a different car, the 2017 Jeep Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
To help improve fuel economy and emissions the Powertrain Control Module (PCM) monitors the HVAC settings for Coolant Temperature Model robustness. The PCM receives HVAC signals in raw data bussed from the HVAC Control Module. These are CAN C signals which indicate the Blower Speed and Driver Side Temperature Door Position. The PCM is required to diagnose these raw signals and set codes for any failures.