[compsciphd]

Volt has 2 maintenance modes it automatically goes into

Engine Maintenance mode: haven't used the gas engine in some period (month?) so it uses the engine for a small period of time (less than my 12 mile commute) so get the engine oil moving.

Fuel maintenance mode: doesn't let average age of gas be over a year. i.e. I filled my tank August 30, 2017 from basically empty. On Aug 29, 2018 it went into fuel maintenance mode and even though I had a full battery, it would only use gas. I was probably around 1 gallon left, I filled it up, so expect around june 2019, it will go into fuel maintenance mode again unless I finish off the tank and fill it up again.