It's probably the same reason - in the US, Toyota wants oil changes and such for the Prius every 5,000 miles. There's a way to turn it off that involves pushing buttons, but I can't help you there. Mine only has about 3,000 miles so far, so I haven't seen the light, but from what I've read it's supposed to come on for a brief period and go off once the odometer hits 4,000, and is supossed to come on and stay on at 5,000 (or at intervals thereof).