Key Fob & Mechanical Key

[Rickker]

Recently came back to my 2024 Kona in a parking lot and could not unlock it. No communication between the fob and the car. Figured the battery inside the fob was too weak (which it was). Tried to open the door with the mechanical key but was not able to do so. Tried holding the fob in different positions near the door handle, and finally it opened. Later, at home, I removed the CR 2450 battery, checked the voltage to be 2.98v with my multimeter. Purchased a new CR 2450, measured its voltage to be 3.20v, installed it in the fob and all is well.

OK, that's the background. Here are some questions, in case this comes up again...

* Is there any way to tell when a fob battery is starting to die, without physically removing it from the case and measuring the voltage under load? A friend of mine has a Honda CR-V and says that a notice comes on the insturment panel when the fob battery is getting weak. That would be nice. It is a PITA to pry apart the fob cases, take out the battery, then have to test it under load to determine if it is getting weak.

* As for the mechanical key, I was not able to figure out how to use it, and will go to the dealer to have them show me. But, even if I had been able to unlock the car with the mechanical key, that only gets me inside the car. What about starting the car and driving home? Does the action of opening the door allow being able to start it, and drive away?

Perhaps this has happened to some of you. Answers/comments are welcome.

 

[electriceddy]

I was not able to figure out how to use it

This video should help, although I have to admit I haven't had the opportunity to check this with mine yet.

What about starting the car and driving home?

Apparently I read somewhere (probably in the manual) if you push the "dead" FOB against the start button (with your foot on the brake)...it will start the car.
BTW, Thank you for posting the battery type (CR 2450).

 

[Rickker]

This video should help, although I have to admit I haven't had the opportunity to check this with mine yet.


Apparently I read somewhere (probably in the manual) if you push the "dead" FOB against the start button (with your foot on the brake)...it will start the car.
BTW, Thank you for posting the battery type (CR 2450).

Thanks for the video, eddy! No wonder I was unable to figure out how to use the mechanical key. Not an easy process, especially if you are under roadside stress. Hope I won't have to use it, but at least I know how.

 

[insightman]

No wonder I was unable to figure out how to use the mechanical key.

After watching the video I daresay nobody would intuitively figure out they have to first use the key to dismantle the door handle to expose the lock where the key can perform its primary function.

Perhaps there's an RFID chip in the fob that, when close to an RFID sensor in the (depressed) start button, turns on the Kona. I think you should tear your fob apart, remove the battery, and test my theory.

 

[electriceddy]

Thanks for the video, eddy! No wonder I was unable to figure out how to use the mechanical key. Not an easy process, especially if you are under roadside stress. Hope I won't have to use it, but at least I know how.

Just make sure your not parked near a drain like this one or you may be disappointed when that cover piece falls in there

 

[electriceddy]

nobody would intuitively figure out they have to first use the key to dismantle the door handle to expose the lock where the key can perform its primary function.

The owners manual shows how to do this but the little pictures are really bad and hard to figure out.
It was after reading that section I decided to download a proper video - just in case. When I do decide to try it, I think I might glue a little thread on the cap so it does not get lost upon removal.

I think you should tear your fob apart, remove the battery, and test my theory.

Ha Ha

 

[Rickker]

After watching the video I daresay nobody would intuitively figure out they have to first use the key to dismantle the door handle to expose the lock where the key can perform its primary function.

Perhaps there's an RFID chip in the fob that, when close to an RFID sensor in the (depressed) start button, turns on the Kona. I think you should tear your fob apart, remove the battery, and test my theory.

You are apparently correct, according to Chat GPT there is an RFID chip. Here is the response from them:

[start of Chat GPT message}
Starting the car with a dead fob battery:

Even when the fob battery is dead, the fob still contains a passive RFID chip that the car
can read at very close range (it doesn’t need battery power for that).

To start your Kona Electric:
Sit in the driver’s seat and hold the fob close to the START/STOP button (touch
the fob directly to the button if necessary).

Press the brake pedal as usual.
Then press the START button with the fob (or with your finger if you’re holding the
fob nearby).

The car should recognize the fob and start normally." [end of Chat GPT message]

However, I am not going to pry the cases apart to verify this. I found it difficult to separate the cases and don't want to chance of breaking something.
OK, it's good to know this, but what is really needed is a way to determine if the battery in the fob is weak and about to die, without having to pry the cases apart.

 

[BobNY13]

I haven't had to start my Kona EV that way, but I have started other fob-based cars by pushing the start button with the key fob. Apparently a standard part of that "keyless" technology.

 

[Das KONA]

Well, I haven’t tried it yet but that key door-opening trick looks like a bit of a PITA. I often leave the dog in the car with utility mode on and locked our 2021’s doors with the key in the fob to attain “dog mode”. But the 2021 had a simple opening to put the key into and the key was within the fob. With our new 2026 not only am I going to have to start carrying the key, but I’ll have to master the pick-up-sticks door opening method.

Sad, but we do like most other changes in the 2026.