Truck was in for same problem twice. First time was charged $527.00. 12 days later back for same issue with DEF fluid sensor light on. Was told fluid was bad and dealer removed and replaced fluid. Had dealer take sample out which they gave me in Styrofoam cup. Sent sample to be tested along with box it came from. All came back good except sample they took. Contacted Nissan corp. about refund and was told they would have to believe service rep.. Second trip back fluid was good, light still on. They changed tank and sensor under warranty. Sansone Nissan auto mall was where I took truck. Does anyone have issue like this.