Power Steering Light

[sıɹɐʎ]

My P/S light came on yesterday. I'm pretty sure it started when I was turning at 5mph on a steep incline. Power steering appeared to still be functional, although I was driving at low speeds. I went and parked at work; when I restarted the car, the light was off.

Unfortunately I don't have a ODB-II reader. My immediate thought was the power steering fluid, but the factory service manual makes no mention of fluid as a direct cause for the light to go on. Moreover, the failsafe chart suggests that "asssist force restricted" is generally applied due to electrical problems rather than mechanical ones.

My '07 Yaris is a little over 25,000 miles, and I'm taking it in to the dealer for scheduled service this Saturday, so I thought I'd have them look at it. Before I go, I was wondering if anyone had any similar stories (I couldn't find any when I searched) or suggestions. Thanks!