840 error code Transmission Fluid Pressure Sensor/Switch ("A") - can this be fixed at home?

Question

Can this be replaced by anyone and/or how involved is it?

Answer 1

P0840 Transmission fluid temperature sensor

This is going to need more than drop in the sensor , you may need to reprogram the TCM, Nissan has a TSB bulletin on this , where reprogram is required.  and flush the transmission fluid. Let this be Dealer only