Theory Of Operation
WARNING: This page is about a different car, the 2012 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
Some controllers communicate with other controllers over the CAN C BUS. The Electronic Shift Module (ESM) continuously monitors BUS activity and reads the messages it needs. The CAN C BUS is also used to communicate the MIL status to the Engine Controller.
Refer to DIAGNOSTIC CODE INDEX and perform the appropriate diagnostic procedure.