Theory Of Operation

WARNING: This page is about a different car, the 2015 Fiat 500. However, it is still accessible from the selected car via links, so may be relevant.

The Push Button Shifter (ePRND) provides momentary push button functionality with included hardware to electrically communicate a vehicle movement request. Each button has a pair of electrical contacts that close to signify that the button has been pressed. The button contacts are electrically at two different voltage potentials. When the button is pressed the contact voltages switch potentials.

The Electric Vehicle Control Unit (EVCU) monitors the ePRND Module switch inputs for desired gear position. When the EVCU detects the transition of both contacts associated with an ePRND Module button press, it will illuminate the appropriate LED (Jewel) on the selected button. Faults associated with the functionality of the LED will result in the ePRND module having all or none of the LED's illuminated.