1 year ago
Last edited at 7:19AM on 2/27/2012
The computer looks at how the engine is running and decides whether to allow Overdrive. Flashing must indicate a problem. The selector must be in O/D any other button must be OD On. It has to be up to temperature 180 degrees. (bad thermostat?) It has to have all sensors ok, and running well. (no check engine light) The voltage passes through the brake light switch. (it can be faulty-wire's broke) Sometimes the parking brake has to be fully released. Finally, the solenoid in the tranny must get the 12 volts, and the solenoid must function, and the tranny has to agree with the computer's decision. (3rd gear at steady speed)
Clogged fuel or air filter or catalytic converter can be issues too.
According to the owner's manual, you should contact your Toyota dealer as this could indicate a problem with the transmission. If a malfunction occurs within the speed sensors or even the solenoids, the overdrive OFF light will start blinking so you really ought to have the car checked.