I'm thinking it's for scan tool purposes and what not. I keep getting this braking error message sometimes ever since disconnecting my battery for my stereo install. When I go to clear the codes, the tool says the engine needs to be off with the key on. Well yeah that's sop for almost all scan tools. So I actually started the car and tried again. but even with the car"started' but the engine not running same error. I thought about this thread but haven't tried it yet. Also it's a cheap $20 scan tool so I thought that could be the issue at first.Interesting... can you find out from them what is/was the purpose of putting it in maintenance mode since all info I found dealt w/hybrids.