"Check regenerative brakes" - Kona 2021

An issue like this has not been reported previously as best as I'm aware.

 

We had this problem - it was related to the 12v battery which died a few minutes later.

 

Received the same warning messages today. Over the past few weeks, the brake pedal would occasionally kick back while stopped. Today was stopped at a light and the brake pedal was kicking back a lot, then got the "Check Forward Collision Avoidance Assist system" and "Check Regenerative Brakes" warnings. The Check Regenerative Brakes remains up. It will be going in on Monday. Hopefully it is an easy fix.

 

It took a week, but after they replaced the ABS pump, it seems to be fixed.

 

Sorry - 2021 Kona EV Preferred. Just hit 2000km. And I’m in Winnipeg, Canada. (The parts had to come from Toronto, so much faster than from S.K.)

 

We have a 3 month old Kona preferred and had this check regenerative brakes warning popping up intermittently. We had brought it to our Hyundai dealer in Kanata (CAN) a month ago but since they did not find what was wrong they sent us back to live with the intermittent warning.

Now the brakes ceased responding when trying to stop the car in a parking slot. We ran in the car in front but at such a low speed that nothing was broken. We decided to tow the car to the nearest dealership (that was 200 k away because the one 100m next to the accident would not take EVs!). It has been 2 days now, they still have no idea.

The brakes were working fine right after the accident. And during, the pedal did not go to the floor but reacted normally except for the fact that it did not produce a deceleration. Scary.

I need to understand where this came from.

 

What means breaks stopped responding? Even when brake pedal pumped to the maximum? Was the break pedal hard to press? Or it just gave in?

 

My wife was driving. She pressed the brakes normally; the car did not decelerate. She pressed hard, like real hard; the car did not decelerate. She pumped the brakes; the car did not decelerate. The car was stopped by hitting the parked car parked in front.

Hyundai said the brake modules had to be replaced. It contains ABS system, the regenerative system and the conversion to hydraulic. I asked them to check if the hydraulic is supposed to kick in whenever the regenerative component defaults… they said they will check with the tech center.

 

Exactly my view - hard hydraulics should always kick in.
Even if regenerative is broken and hydraulic brake pump goes belly up, brakes should work by stepping in hard to the brake pedal.
Then the only problem could be with people not pressing the brake pedal hard enough as they expect normally working stuff.

Let us know what the dealer will report.

 

May or may not be related, but there is a recall #199 related to updating the brake system software.

 

After 2-3 weeks of wait, we have our car back with a new braking module. The answer to the question I had posed regarding whether there is a fail safe on the regenerative braking is: no. Unfortunately, if the regenerative brakes fail, the hydraulic brakes are not triggered.
This is probably what happened. The regenerative brakes failed so no braking was produced. The fact that we had a sporadic 'check brakes' sign is re-assuring: a brake fail should not happen if you go back to the dealer to have it checked.
But the fact that Hyundai had originally sent us back home with a defaulting vehicule because they could not locate the issue with the brakes is appalling to me. If other out there have this sign, don't let Hyundai send you back home because they can't find what's wrong. It could be very dangerous in my opinion.

 

... regenerative brakes fail, the hydraulic brakes are not triggered ...

I have significant doubts about that statement. The hydraulics *are* the backup for all the things
that can go weird during regen -- bumps of certain periodicities, panic braking, moving to Neutral.
If your statement was correct, going to Neutral while in motion [a common tactic to clean rust off
the rotors] would make the car an unstoppable juggernaut.

Now, a failure of the hydraulic system *itself* is a different story.

_H*

 

Agreed. I could not believe it myself. But this is the answer I got from the head mechanic at the Hyundai dealer who had to validate with Hyundai engineers (where? Canada or Korea?).