Brandt

Hi guys im new on here and dont know if im posting in the right spot. But my problem is i bought a 07 is250 about a month ago and the nav didnt work. It has the program cannot be read see dealer. But today i took it in today to check and see if i had tire sensors. It has after market wheels. But when they were programming the sensors they had to reset the ecu. When they reset it and the scanner was running my nav came on then when the scan was done it went back off. And the buttons on the right of the screen dont do anything. The buttons are Map/voice, dest, and one more i cant remember. Any suggestions would be helpful.