In that case any of the 2 terminals serves (positive or negative), since you leave the entire system without food. But the most advisable thing is to remove the negative.
Now I understand that these vehicles have a small screen (display) on the board, when it requires oil change appears "INSP". The way of turning off that legend is as follows:
1. Identifies the button that is located on the board and you will keep it pressured (pressured until the end of point 3)
2. Girdle the key to Ignition position
3.In the display you have to remove the letters INSP and instead of that lines you must appear some lines
I hope it serves you