A family member owns a 2015 Jetta 1.8T. She asked me to check the oil as the "oil lamp" came on when starting the car. I checked the level and it was a maybe a smidge above the bottom cross hatching on the dipstick, so I am thinking it may be about 7/8 quart low. After checking the oil level I started the car and did indeed see the illuminated yellow oil lamp warning so I checked the manual and found that this means low oil level. The manual did not however mention how low the oil would have to be before this warning came on. So I guess I am asking, is less than 1 quart low enough to trigger a low oil light, or even be concerned? When she asked me to check it I told her not to drive it until I could check it out. Once I saw it was low I told her to pick up a quart of either M1 0w40 or Castrol 0w40 / 5w40. She said she will top it off tomorrow so we will see what happens then I suppose.