Electric power steering

[Geoff Peace]

Yaris 1 litre 2005 model with electric power steering. Had a small problem with this the other day, warming it up on the drive in this cold weather and the power steering warning light came on. Handbook states if the engine is raced for longer than 30 seconds the power steering will decrease to prevent overheating, restart the engine and drive. This I did and the light went out and it has been O.K. since. I have owned the car since new and this has never happened before, the engine has been raced for the MOT for instance to ensure that the engine is hot. Does anyone know how this system operates? The motor appears to be under the dash and must engage with the steering column directly or through some form of clutch. Does it reverse rotation for turning left and right? Is it controlled by an ECU or some mechanical means? Does the motor run continuously or only when required for turning? Iwould dearly like to know the answers to these questions for future maintenance. If anyone knows the answers or has any information I would be most grateful. [The Haynes manual only deals with the hydraulic form of power steering]
Regards Geoff Peace.