I need some help! In the past 6 weeks my 2005 prius has been getting bad gas mileage; around 40 mpg when I usually get 50 to 52. I know some would say it's bc it's winter and I'm using the heat. However it hasn't been that cold in Denver so far (it will be next week) so I haven't been using the heat much. Plus last winter when I used the heat my gas mileage didn't change. Now for the past week when I start my car it makes this "kunk kunk kunk" noise that I have not heard before. I just replaced the regular battery last month because it was showing a check brake sign on my dash. They checked my brakes and said everything was fine there but that the battery needed replaced and it was throwing off "erroneous signals." Hence the check brake signal. I don't know what's going on at this point! Please help! Thanks P.S. my check brake signal is still on. They say it's a fuse that needs to be replaced for $85 Posted via the PriusChat mobile app.
That mechanic probably didn't know much about the prius. Can you post a picture of the brake light? I can tell you it's not a fuse
Did it sound like bad timing, eg a real rough engine along with noise? Do you stop and restart to correct or does it correct itself?
Is it a Toyota dealership doing the diagnosis, or independent mechanics? If there's a brake warning light there should be codes. Toyota has propriety (Techstream) software for reading the codes; best have them check it out, and post the codes here too.
Ditto getting the diagnostic test codes from Toyota. Anything else is just guessing, and meanwhile you're driving a possibly dangerous vehicle. If the light is red, that means stop driving. You should be hearing a quiet ratcheting noise every two or three times you apply the brakes. That would be normal. Is the noise you're referring to slow in frequency, and continues for a long time? Is it unaffected by applying the brakes? If so, it sounds like the coolant control valve sounds when it goes bad, unrelated to the brakes. That valve is behind the left headlight, if that helps narrow it down.
Hi Andrewclaus -- I've just noticed a sound happening when I hit the brakes, but not every time. I don't know that I'd describe it as ratcheting, but it sounds like something that is normally running skips a couple times. What is that normal sound you're describing?
it's the same sound you get from behind the dashboard when you open the drivers door to get in. kind of a buzzing for a few seconds.
Ah - that one I'm familiar with and indeed have heard it all along. What I'm hearing is different and might be more similar to OP's sound!
Could be a wheel bearing, CV joint, suspension bushing, bad tire, or a dozen other things. Like Douglasjre says, we need more info. Melshot, what's going on?
