About 4 weeks ago I got the 2025 Prius Plu-In Hybrid XSE Premium. At about 66 miles on the odometer I noticed that there is a scratching/grinding-ish sound and pedal sensation when the car transitions to friction braking. If I press the pedal quickly it goes straight into friction braking, and I hear/feel it. This is only heard/felt at low speeds (20MPH or below). This is NOT ABS going off. I know what that feels like, and have experienced it in this car as well. I took it to the dealer and they claim it’s normal. They said pads and rotors look fine. However, I tried another Prius on the lot, and it does not behave this way. Anyone else here experience this? My previous car was a 2022 Lexus ES300h, and it did not have this issue with brakes.
My Prius gets that way every time it has sat parked over a rainy night. I fix it, the next time I drive it, by shifting to Neutral for my first 3 or 4 stops. That rubs off the flash surface rust that has formed on the rotors, making the grinding/scratching/vibration.
I see. Mine just never ever goes away. I even tried that thing where you take the car to 40mph and stop about 5 times over a few days. But this happens at every single stop, or when just creeping forward with foot on brake.
If you're really only at 66 miles over 4 weeks, clearly it's getting very little use, and it may have been sitting around the dealer some time. There could well have been a fair bit of build-up, and you're not managing to get through it with your usage pattern. I'm pretty certain it can improve, and if you did keep working at the stops it would help. (Do the stops in neutral to get those pads working.)
My 2021 Prius Prime Limited PHEV brakes at over 40,000 miles are still whisper-quiet. I hardly use the friction brakes; so, chances are that the brakes are still brand-new. This was reported by other posters, too. It seems to be a manufacturing defect. Perhaps there is some something wrong with the pad-wear indicators or other brake hardware.
@KMO I am at 600 miles now, and sadly it is getting worse, not better. I meant to say I noticed it when it had just 66 miles on the odometer.
Considering where you live, and because your dealership hasn't helped you, I'd consider taking it to TCCN Automotive out in Homer Glen for an evaluation. I'd trust them far more than any dealership. Even if they don't fix it for you, they can figure out what's wrong so you can take that info to the dealer and have it fixed under warranty. In case you don't know TCCN, it's a Toyota/Lexus/Scion specific repair shop owned/run by TheCarCareNut, a former 15-year Toyota master diagnostic tech and youtuber that opened up his own shop about three years ago.
Ha ha, you say it only happens below 20 mph. Are you sure you are not hearing the “acoustic vehicle-alerting system” that turns on below 22 mph with the engine off and mistaking it for a brake sound, sending everyone on a wild-goose chase? Here is how my Gen 4 PHEV sounds—much louder in reverse than in forward. I mistook it for the transmission grinding before I found out what it was. LOL It was less loud in my 2020 Prius Prime XLE than in my 2021 Prius Prime Limited.
Just to add onto Gokhan's post. Test by driving right around 22-23mph. If the sound suddenly disappears when you hit 23mph* and suddenly reappears at 22mph, Then what you're hearing is coming from the speaker. You can also test by forcing the engine to start when you're below 23mph. As soon as the engine starts, the noise will disappear. If the noise doesn't correspond to any of this, then it's something else. Since you say it's linked to braking, then it probably is. *I'm pretty sure 22/23mph is the cutoff, but maybe test +/-1mph to be certain.
This is not a speaker sounds. It’s grinding sensation through the pedal. You can also hear it, it sounds like metal grinding, and not the synergistic EV noise it makes.
I have 1700 miles on mine and I’m noticing a slight intermittent break grinding sound during initial driving but it goes away. Just started a few days ago. Almost like the sound my 2009 made after it rained and was parked for a while. Hopefully this won’t be a regular occurrence. Yesterday I got out of my parked car and heard a high pitched screechy metal sound. Only lasted a few seconds and haven’t heard it since. WTH I’m trying to remind myself that most things can be repaired but my nerves aren’t believing it.
Then I'm back to taking it to TCCN. Can you tell if it's happening just in regen, physical, or both? I'm wondering if there's something caught in one of your brake pads. Maybe a small rock or something is stuck and that's what's you're feeling. SM-S901U ?
OK then. The Prius EV speaker sound is a grinding sound though. When I first heard it, I thought the transmission was grinding. Perhaps shoot a video and post it here so that we can hear this sound.
@KMO mentioned stopping in neutral, which I haven’t tried. Holy crap it helps! The rotors seem warped, and aggressively stopping from high speed in Neutral seems to make the grinding much quieter, and most importantly, the grinding sensation through the pedal almost goes away. However, it comes back after a few hours and I have to do an aggressive brake in Neutral again.
Aggressively not-stopping is better still. I mean brake a lot, and hard, but don't actually stop. That way the rotor cool-down is a bit more even, which helps keep things smoother longer.
Depending on how interested TCCN might be in your braking issue, it may be some time before you can even get an appointment with TCCN. I recently called and left a voicemail and got a return voicemail informing me they are scheduling "typically about 2 1/2 months" out. From some of his videos, it seems he may accommodate an earlier appointment if the problem is "interesting" (and maybe he can make an interesting video out of it. I will say in the almost year, I've had my car, maybe this has happened once or twice and I attribute the event(s) to times when I wasn't driving as carefully as I usually do. And also probably my lack of knowledge on how regenerative braking and normal braking are supposed to work.
