I am on the road and getting some kind of mild electric motor noise every 15 seconds or so. It sounds like its under the dash and its really only audible with the windows up. Brake Booster or?
i thought the booster was a buzzing noise. coolant pump maybe? or hvac vent door actuator? how many miles on her?
Bad abs module it has a leak. Very common very expensive to repair. Use search forum and search Abs module
"Mild electric motor noise", "buzzing noise", people hear different things. There's a pump driven by an electric motor, so it would be fair to call it an electric motor noise, even if some people describe it as buzzy. How often it has to re-pump depends on a lot of things, such as ... how often you're using the brakes. Every time you use them, some fluid is transferred from the accumulator out to the brakes, and then back to the reservoir. When the accumulator pressure is low enough, it's pumped back up. If you're in stop-and-go traffic, that'll happen often. If you're sitting there not touching the brakes and the pump has to repeatedly cycle, that's another story. Before deciding every worst-case scenario is actually happening to you, you might plug in Techstream and just watch the live accumulator pressure reading, see how noticeably it's dropping between pump runs when no one is using the brakes.
Its 230k on the v and the noise is coming from under the hood near the brake systems, drivers side firewall. I will check it with techstream in the next day or two. I notice something is pulsing the brakes at very low speeds as well.
Check if you may subject of Voluntary fix by Toyota https://static.nhtsa.gov/odi/tsbs/2019/MC-10164922-9999.pdf . 31 August 2021/unlimited mileage.
Hi, welcome to PriusChat, where a lot of people come looking for accurate information about their Prius cars. The 'campaign ZJB' document linked above applies only to 3rd generation Prius liftback and Prius Plug-in (PHV) cars, not to the v or the c. The end dates vary by model year: So it's already over for 2010s (unless anybody's got one that hasn't rolled 150k by now). For 2011s through 15s, it is still in force through August 2021 and then to your tenth year or 150k miles, whichever comes first. It is a replacement conditioned on specific failures ("certain internal malfunctions of the brake booster and brake booster pump assemblies"). It is good to remember that in the 3rd generation Prius, those are two different assemblies: There is a list of trouble codes that may mean the covered failure has occurred. They are codes that can also be set for other reasons. Sometimes a few simple steps of diagnosis will reveal that something else has caused the codes you have, and that replacement of one or even both these assemblies would not be the necessary solution.
They are not covering the Prius v in this program. That's the heart of the issue because they are covering the hatchbacks.
Are you still having this issue? Did you find the cause/solution? my 2007 Prius is doing this too. 220+k miles. Happens when accelerating, coasting, idling and noticed today after turned off for 5 minutes or so….
There are a lot of differences introduced in the Gen 4 brake system, which you can read about by following the posts in the discussion over here. I don't know that we have a lot of experience yet with Gen 4s above 300k miles, but there are enough differences in the system that the news could turn out to be good.
Thank you for that update! I stopped at Toyota and they mentioned that could be it. He didn’t seem concerned - like I could drive with it til a light/warning comes on. But a couple times when I started it the car started moving when I put it in gear and the brake wouldn’t stop it/engage for a few seconds/feet. Makes me a bit nervous that could happen at a higher speed…
Yes, 2nd and 3rd gen Prius may have brake booster problems but many also do not have issues even after 400k or 500k miles. I am wondering, what kind of prevention we can do. I doubt regular 3 yearly brake fluid changes can help. Even at 100k miles 5 years brake fluid change interval, the water content is still only 1% and additives are still at 90% level. What I understand, some batches of brake boosters are bad and revised units have different production/sticker numbers.
In the Gen 3 world, there was definitely a batch of bad accumulators (Gen 3 splits the works into a couple different assemblies) that got manufactured with the metal bellows slightly undersized, so it banged around inside the can on bumpy roads, and developed cracks early). Those were recalled, and you could recognize them by the labels. I'm not aware that the issues with the boosters/actuators are of that kind. Sometimes we're a little free with the idea of a manufacturing defect when we see things wear out ten years and near-lunar distance after being manufactured.
My cycling noise went from happening every 15 seconds, to every 8 seconds to now being every 4 seconds. And it continues after I turn to car off for a few minutes. there’s no code indicating anything is wrong. I’ve gotten used to it. But I wonder about what happens if whatever’s making the noise (brake actuator motor/ABs?)) stops working, will my brakes still work? I can keep ignoring this for a few hundred thousand miles, but if it’s dangerous to myself and other drivers, I’d rather address it…
there's no telling if or when they might fail. but toyota provides a safety back up. there is a manually activated hydraulic system which simply requires more pedal pressure. in a panic, that comes naturally
