Noise when Regen Braking Kicks in

[rizulli]

My Kona has been in to the dealer three times in a last couple of months, all related to regen braking.

First was the brake software recall, no big deal.

A couple of weeks later the car started throwing "Check regen brakes" errors on the dashboard. I don't have the exact wording as it always occurred when my wife was driving. Took it in to the dealer (twice) and they determined some form of brake module needed to be replaced, 3 week delay and a gas powered loaner later and the problem was solved.

Soon after we started to notice a grinding noise when the regen brakes activated. Only when it activates mind you, lift the foot off the accelerator and there is a bit of a grinding noise as the regen activates and then it is gone. The car is at the dealer right now and I've already done a trip back because they 'couldn't replicate the problem'. Took a video of it (below, you can hear it when I lift my foot from the pedal) and left the car with them again after talking to the tech. My wife says the noise has been getting louder.

Anyone else have any info on this latest issue? I'm assuming something isn't secured properly after the brake module replacement, but I honestly don't know.

 

[m4rk0]

[..] Soon after we started to notice a grinding noise when the regen brakes activated. [..]

Hi rizulli,

That's exactly the issue I am having since yesterday with my Kona 2021 FL 64kWh, 1200Km / 745mi so far, barely one month old.
Car did not show any noise until yesterday; brought it in to the dealer because it needed replacing a rear light, so they lifted it, removed rear bumper, replaced light and put everything together.
Now, my car shows a reproducible grinding noise when regen breaking is set to level 2; level 1 is not enough to engage it; level 3 tends to increment the 'number of grinds' from 3/4 to 5/6 and their loudness.

Do you have any update on yours? Have you been able to get it fixed? Please, could you share some details about your Kona? (FL or pre-FL, kms, whether it has increased on the number of grinds and their loudness, and so on).
I spent a few hours so far trying to find other people having the same issue but it seems I managed to find only cases where rattle/clicking sound happens when coasting at slow speed and/or increase in frequency when going faster. It seems to me we are dealing with a different issue, at least under different conditions - so far.

Thanks.

EDIT
Just found out you have a pre-FL Kona

 

[rizulli]

I am pretty convinced it was the result of the dealer not tightening something properly when they replaced the brake module.

After I convinced them that the problem existed and them talking to Hyundai head office, they ordered in a part (they were never able to tell me exactly what it was, the person at the front desk thought it was a mount of some sort). After the part was swapped out I haven’t had any issues.

The interesting thing was, when it got super hot out (35-40 degrees C) the noise basically went away. This is why I’m leaning on my theory of the dealer not tightening everything properly the previous time they were working in there.

 

[m4rk0]

Thanks for your reply.

I see; I have to wait for the service to have the car in and check what's going on. I will update this thread when I hear back from them.