First I want to apologize if there are threads about this. I did do some searching and didn't find anything related to my possible issue. Some background. I have a 2009 and just turned 100K. For the first time that I can remember the blower cooling fan came on the other day. It stayed on for maybe 3 or 4 minutes then shut off. My MPG plummeted during the time it was on and the rest of my trip which was probably about 25 miles. By plummeted I went from my normal crusing mpg of mid 50s down to the low to mid 40s. I did not get any warning lights and the next day the car was back to my normal computer MPG operating range. I guess my question is has this happened to other people. And is this a harbinger of things to come. Meaning could this be a sign my battery could be going? Should I take it to the dealer to see what the readings are of the modules? Thanks.
Were you running the air conditioning? If not, your battery most likely got too hot from use+increased ambient temperatures. When the battery is too hot, computer decreases the allowed amount of current in/out of the battery, and as the result Prius becomes not a hybrid any more so mileage drops significantly. Running the air conditioning in hot weather would benefit both the battery and driver. The battery should be fine. No need to go to dealer if there are no check engine lights/codes. Another issue if you carry dogs frequently or drive with your windows open on dusty roads. The battery cooling system and fan can get clogged. Search priuschat for pictures and instructions on how to clean. Thanks, - Alex
