Key fob interference with phone?

Discussion in 'Hyundai Kona Electric' started by EVRIGREEN, Jul 10, 2019.


    EVRIGREEN New Member

    I read in the manual that I could experience interference between my key fob and my iPhone (getting my Kona EV this weekend). Apparently it happens when the phone and key are in close proximity. Has anyone experienced this? I plan to carry my key and phone in my purse, so this would be a bit of a headache.
  2. KonaTom

    KonaTom Active Member

    Hasn’t been an issue for me
    electriceddy likes this.
  3. FlbrkMike

    FlbrkMike Member

    The only problem the I've had (and it was like this with my Fusion Energi as well), is if my iPhone and my key fob are in the same pants pocket then the "touch" doorlock won't work. Otherwise, no problems.
  4. Didn't know you carried a purse:D
    (sorry Tom)
    Lex23 likes this.
  5. SkookumPete

    SkookumPete Well-Known Member

    It'd happened to me two or three times. I think the two devices have to be touching or very close.
  6. Your key-fob just like your phone has a fun little disclosure that’s very common and is a FCC requirement (and similar worded disclosures elsewhere) that goes something like this:

    Your device must not create unwanted interference but must accept any unwanted interference.


    Because these devices talk on “unlicensed” channels, they are still regulated but just about anyone who follows the regulation can use the spectrum without a license. Wifi, Bluetooth, microwaves, key-fobs, etc all use this same 2.4ghz unlicensed spectrum and it’s incredibly congested.

    So why is the manual telling you that your phone and key-fob can interfere? It’s pretty standard after all no? It’s actually super simple and super complicated why they’re disclosing this issue. Your key-fob is constantly powered and broadcasting as it’s a smart key, more so the smart key is designed to be -very- low powered so the car should only turn on inside the car, this way when you’re near your car someone can’t just jump in turn it on and drive away. In theory. But the second side of this super underpowered key-fob is your phones much higher powered (.1-1watt haha) powered phone can easily prevent it from working. If your key-fob isn’t working, especially if the batteries aren’t fresh, you’ll generally know why. Just a matter of inches can make the difference.
  7. victor_2019

    victor_2019 Active Member


    I do experience it from time to time.

    although not as bad as I get on my honda clarity which is constant, if the key is in same pocket as phone, the keyless entry fails almost every time. on the hyundai it's more rare but it does happen.
  8. mikeselectricstuff

    mikeselectricstuff Active Member

    This is a simple shielding & damping effect - the metal phone is damping the 125kHz (maybe 134 in US/Can?) signal that the car sends to the fob to interrogate it. If the phone has Qi wireless charging, that will make it worse as the charge receiver coil and ferrite shielding will absorb a lot of the energy.
  9. KonaTom

    KonaTom Active Member

    You never heard of a “man purse”.
    electriceddy likes this.
  10. I tend to travel light;)

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