Nissan Repair: crank sensor, crank sensor, vent line

Question
The mechanic told me that the crank sensor needed to be changed ($ 550) and after 2 weeks the same yellow light (please check engine) came back. A different expert in a auto-parts store told me that the code showing was P1440.
Could it be that they never changed the crank sensor but only pushed it in until the light on dashboard disappeared?

Answer
Vikki,

The code P1440 is for the evaporative system and it shows to have a leak.  That is, probably the gas cap was loose and after tightening the cap the light should turn off after a few times of driving the car.  Depending on your year of Nissan you might have a loose vent line or rotted hose.  But, usually, it is the gas cap.