Having driven my 09 prius for 3 years, I am very familiar with its habits. For the last 2 weeks, the hybrid battery energy monitor has been constantly 7-8 bars green. I have driven as much as 150 miles highway at a time and never left the green. During that time, mileage has dropped by 7-8 mpg. When going uphill, I only get a flicker of boost from the battery & elect. motor. Meanwhile the ICE is winding up trying to keep me up with traffic with very little electrical help. The battery keeps getting charged all the while. In town I occasionally get blue bars, but never less than 6. These symptoms have never occurred before. Longer trip coming up...Thoughts on this issue please.
Que Kermit The Frog singing "It's not Easy being Green". Seriously. If it is your original 12v? That might be a good place to start. Otherwise? Go forth to thine dealership, with brazen heart and good ale at the ready.
Try disconnecting the 12V negative for 5 minutes to do a hard reset of the HV and battery ECU. While disconnected, test the 12V. You should have more than 12.3V in the disconnected state.
