Start with this first
Check you battery voltage / charge it ... Rzr's do stupid things when the battery gets weak
Check your battery cables and terminals confirm they are tight and clean
Check your main chassis ground in the rear driver side wheel well . This is a stud with a nut where your main ground attaches clean and confirm it is tight
Check for any wires that have possibly rubbed through the insulation and maybe grounding
Here are some other possibilities
P0916: Gear Shift Position Circuit Low OBD-II Trouble Code
The gear shift position sensor/transmission position sensor tells the TCM and ECU what gear you have selected with the shifter. If there is a low voltage signal on the transmission shift position sensor circuit, a P0916 DTC will be saved.
check the round sensor on the side of the motor where the shift cable is.
Maybe the connector is unplugged or cable is damaged.
Could be the whole sensor is bad.