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Kurt Kennedy
Kurt Kennedy, ASE master with L1
Category: Hyundai
Satisfied Customers: 89
Experience:  Shop foreman at Auto-Lab of Texas
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HOPEFULLY KENNEDY - QUESTION I need to understand the

Customer Question

HOPEFULLY FOR KURT KENNEDY - A FOLLOW UP QUESTION
I need to understand the keyless entry system on my 2012 sonata hybrid. I am building a custom interface for a new product which will share control features.Is the remote key 1 way or 2 way
what frequency (or frequencies) does it issue
what frequencies does the car send back to the key fob.
when I approach the door, where is the antenna that detects my proximity located for driver, passenger, and trunk
when i approach the door does the central logic send a Who R U request
Do I send back more than I AM
how does central logic determine i am outside cabin of car
once I am in car, how does central logic know i am in cabin
are seat occupancy sensors used to verify occupants
where is the HF pickup antenna or antennas inside the cabin
where is the LF pickup antenna or antennas inside the cabin
How does the key fob notify the central logic who I AM (HF or LF)Whoever answers this - is there a way to get back to you specifically for follow up questions?
Submitted: 6 months ago.
Category: Hyundai
Expert:  Kurt Kennedy replied 6 months ago.

This is Kurt Ill be back later tonight to answer all this.

Customer: replied 6 months ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 6 months ago.
Kurt, it is 10:21 here now. what time do you plan to call or write - either works for me.I will go to bed by 11:30. I should not have clikced phone - a written response is fine - I will wake up to it.
Expert:  Kurt Kennedy replied 6 months ago.

Sorry, its been a long night here I am in Houston and the weather has been something else the past month with all the flooding.

What do you mean by 1 way or 2 way?

There are 125khz transmitting antennas normally in the door handle to reconize when the key is approaching the car.

The who r u request as you call it, happens a few ways. The first time is when the first antenna reads the key, turns the lights on and unlocks the door. that is when that particular antenna makes sure its the right key for the car. Once you are inside there is a steering lock ECU that once you hit the start button once, it verify s the key code is correct and will unlock the steering wheel, It happens again from some type of "immobilizer ECU" or "Transponder ECU" that when you push the button to start, it operates on a 300khz signal and IT verifys its the right key for the car, and allows ECU to ground the starter relay to start the car.

No seat occupancy sensors are used in the smart key process. there are other pre reqs the ECU has to see as well such as a signal (input) from the brake light switch.
There are multiple locations for the HF antennas in the car. Most common is the ring around teh start button its self, its normally called a immobilizer booster.

The outside car is generally the handles for the LF (door handles are normally controlled by the central computer or in some cases the smart key ecu)

The Key verifiys the key code through multiple steps of the process and through multiple ECU's.

I just kinda rambled on, and tried to answer all your questions, please feel free to ask whatever I missed haha.

Thanks!

Expert:  Kurt Kennedy replied 6 months ago.

Did you get my last response? Did it make sense, or create any more questions?
Thanks!

Customer: replied 6 months ago.
Kurt, I am first trying to understand what happens when the sart key is outside the car.I assume the smart key is not constantly broadcasting (to conserve battery), raising question 11. Does the Hyundai constantly broadcast a wakeup signal to wake the smart key fob
2 if so, what frequency does the hyundai put out,
is is AM or FM
Can you say more about what the coded message looks like.3 If the key is the first to initiate the dialog:
does it broadcast over 125 mhz
is it AN or FM
how is it coded – what does it say?4 Is the key a bi-directional transponder?What frequencies does it receive? AM or FM Data structureWhat frequency does it respond over while outside the car
AM or FM Data structure5 does the smart fob use different frequencies once inside the car?What frequency (or plural) and data structure does it receive inside the cabinWhat frequencies and data structure toes it reply with inside the cabin.6 How does the car know the owner has exited the cabin, so he can lock doors.
When the smart fob exits the cabin are the same send and receive frequencies used by fob?
Does the tell the car it is outside, or does the car probe for a fob outside.If two authorized keys are in the car, can either lock the car, or must it be the driver who just shut off the vehicle.Thank you Kurt.If I have more questions we may set up a phone response.I know my requests are detailed and time consuming. Please suggest what might be a reasonable amount to fairly compensate you for the extra time.Jim Souder ***@******.*** (###) ###-####
Expert:  Kurt Kennedy replied 6 months ago.

Just confirming I see your response, and I will Reply tomorrow. I have material at work I will need to reference to access so i can give you the most correct and detailed info I can.

Thanks!!

Customer: replied 6 months ago.
Kurt, have you had any success in getting the information you require to answer?
thanks
jim
Expert:  Kurt Kennedy replied 6 months ago.

Sorry I have not replied, been a busy past few days. I do have about half of the answers done, ill try to get the other half tonight and send a reply. Sorry its taking me a few days!

Thanks buddy!

Customer: replied 6 months ago.
Kurt, I cant tell you how much I appreciate your effort - I could never do this without your help.
ThanksJim
Expert:  Kurt Kennedy replied 6 months ago.

Anytime man!! These types of questions really break up the nightly questions. Although this one is having me really think and do some research. I like it!

1. Does the Hyundai constantly broadcast a wakeup signal to wake the smart key fob

Yes, There is constantly a coded signal being sent out looking for the key in the pocket

2 if so, what frequency does the hyundai put out,
FM and is 433.92 Mhz (I think thats what you are looking for?)

Can you say more about what the coded message looks like.

Sorry, for that, I have no idea. its a very crypted code to prevent theft, I do know that.

3 If the key is the first to initiate the dialog:
Like stated above, its at 433.92MHz
how is it coded – what does it say?
Once again, that I am honestly not sure of. I made a phone call to a contact I have a manufacture who is responsible for the smart key operations on that brands car and he would not mention any of the code/encryption to me.

4. Is the key a bi-directional transponder?

They offer both. Unidirectional and Bi-directional. Just depends on the model and package.

What frequencies does it receive?

FM and 125KHz

What frequency does it respond over while outside the car
FM and I am not sure about the last part of this question.

5 does the smart fob use different frequencies once inside the car?

Yes, it uses RF inside the car to send signals and different verification codes to different control modules to start the car (smart key computer, Engine control computer etc)

What frequency (or plural) and data structure does it receive inside the cabin
Not sure on the Data structure? Not sure on the frequency, I ll have to double check that tomorrow.
What frequencies and data structure toes it reply with inside the cabin.

Ill check on this tomorrow as well.

6 How does the car know the owner has exited the cabin, so he can lock doors.

through the in car antenna's located in various places (Upper B pillers, head liner, etc.)

When the smart fob exits the cabin are the same send and receive frequencies used by fob?

Correct.

Does the tell the car it is outside, or does the car probe for a fob outside.

It no longer receives the RF signal and frequency "ping back" from the key on the inside antennas. which is why you cant lock a smart key in the car.

If two authorized keys are in the car, can either lock the car, or must it be the driver who just shut off the vehicle.

This is very confusing for the car, even more so if you have memory seats assigned to keys, radio stations and climate control settings. both can lock/unlock the doors.

Sorry thats all the Info I really have. but please feel free to explain anything I had questions on, or did not answer clearly. I will do my best to get the most accurate answer for you. Sorry it took me a while to get back to you!
Thanks man!

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