One problem related to back up lights has been reported for the 2008 Toyota Prius. The most recently reported issues are listed below.
The 2008 Prius has a digital display. Sometimes when the vehicle starts up there is no information displayed on the screen. Nothing shows what gear (reverse, neutral, forward) it is in. There is no speedometer display. No odometer display. No fuel level display. At the same time that the dash does not light up, I have noticed there is no backup camera or backup lights when the vehicle is in reverse. In addition to the above, the start button will not fully shut down the car. It will cycle between accessory mode and full start when the button is pressed. I have noticed that when the problem is happening the vehicle is also not keeping track of the miles driven while the dash is not displaying - so when the dash does start working again, the odometer is not showing true mileage. After getting the vehicle to finally shut down, I have sometimes had the issue not present the next day at startup. Other times it will last through several starts and stops. I have read online that this problem is consistent with a faulty combination meter. And I feel it is a safety issue.