The hybrid battery cooling fan may become restricted, resulting in illumination of the Check Engine Light and an associated fault code p0A82. Our technicians tell us that keeping the cooling fan clear of debris will help keep this fault code from setting and also may prolong the life of the hybrid battery.Google+
Car Problem Reports
Toyota Prius Restriction of the hybrid battery cooling fan may cause illumination of the Check Engine Light
Toyota Prius Problem
Average Mileage: 134,115 mi (67,345 mi - 170,000 mi)
Visitor, 2005 Toyota Prius, 170,000 mi
So why isn't there some kind of housing or filter to cover the fan and keep debris out?