I have 27K miles on my car and have gotten the oil changed 2 times so far (both times when the MM was at 20%). The MM is currently at 30% and I'm thinking of changing the oil soon (when it's at 20%).

I have never had the MM give me another code at all. My question is does the oil indicator need to reach 0% before other MM indicators are displayed?

Should I wait until the MM shows 0% and then reset my indicator or is this just because at 27K miles, the MM codes have had no need to display?

Thanks.