Toyota Repair: Overdrive Off light flashing, toyota avalon, transmission troubles

Question
I have a 95 Toyota Avalon. My OD OFF light just started flashing steady. I have no transmission troubles at all. It doesn't matter if I turn OD on or off, it still flashes. About 1 month ago, my check engine light came on. (husband thinks its a sensor) Could it be related? Disconnect the battery and everything is great...for a while, then lights start up again. I want to sell it soon and don't want to put alot of $$ into it, but don't want to sell it with a major problem either. Thanks

Answer
The engine light and the O/D light flashing is probably related, you should have a diagnostic scantool connected to find out what the trouble codes are, most larger autoparts chain stores are doing this at no charge, once you have that information I can probably be of some help.