Theory Of Operation
WARNING: This page is about a different car, the 2020 Jeep Renegade. However, it is still accessible from the selected car via links, so may be relevant.
The Electronic Shift Module (ESM) monitors the shifter position sensors for electrical failures. If one or more position sensors are faulted, A DTC will set and the shift indicator LEDs may be turned off depending on the severity of the failure.