Although it's not officially a recall, it is almost considered the same thing. You see, in the US, if a widespread problem doesn't really present any safety concerns then it's not an official safety recall. The company has opted to pay for all repairs though in the same way a simple recall works. Toyota is calling it a 'customer satisfaction campaign'.
The problem itself is down to the electric water pump. Toyota says that the pump can potentially let air bubbles into the coolant, disturbing the stream of waterflow and circulation around vital engine components. In a worst-case scenario it could cause the car to overheat and lose power, the company says. No reports related to injuries or accidents have been made in relation to the problem.
Toyota Australia says this affects vehicles built between August 2003 and May 2007, which are all fitted with a warning light that will illuminate if problems arise. Customers won't be asked to take their cars into a Toyota dealer to have the part replaced until February next year though. In the meantime, if, in the unlikely event, your Prius warning light does come on, Toyota advises to contact a local dealer right away to have the pump replaced free of charge.