Dead Key Fob Battery medium urgency

2024 Hyundai Kona Dead Key Fob Battery (US): How to Unlock, Start, and Replace It

If your 2024 Hyundai Kona key fob suddenly won’t lock/unlock or the car won’t detect the fob, the most common cause is a dead fob battery. The good news: you can usually still unlock the door and start the vehicle using the built-in mechanical key and the Kona’s backup detection method. Then you can replace the coin-cell battery to restore normal operation.

Understanding Your Situation

The key fob uses a small coin-cell battery to power its radio signal. When the battery is weak or dead, the Kona may not respond to button presses and may show a “Key not detected” message, even though the fob is with you.

🚀 Immediate Steps to Take

  1. Unlock the driver door with the hidden mechanical key (inside the fob) if the buttons don’t work.
  2. Start the Kona using the backup method: hold the fob right up to the START/STOP button (or the designated key detection area per your owner’s manual) and press the brake, then press START.
  3. Replace the fob battery with the correct coin-cell (commonly a CR2032 on many Hyundai fobs, but confirm your specific fob/owner’s manual), then test lock/unlock and remote start (if equipped).

Your Options

DIY key fob battery replacement (coin-cell)

Cost: $3-$12 Time: Same day

Open the fob case carefully, swap in a new coin-cell battery, and reassemble. No programming is typically required for a simple battery change.

âś“ Pros:
  • Fast and inexpensive
  • Usually restores full fob range and reliability immediately
âś— Cons:
  • Risk of cracking the fob shell or damaging clips if pried incorrectly
  • Using the wrong battery type or installing it upside-down can cause continued issues

Battery replacement at a parts store or dealership

Cost: $0-$25 Time: Same day

Have a technician or counter staff replace the coin-cell battery for you (service availability varies).

âś“ Pros:
  • Less risk of damaging the fob
  • They can confirm the correct battery type and orientation
âś— Cons:
  • May require a trip during business hours
  • Some locations charge labor or require purchase of their battery

Replace the key fob (if the fob is damaged or still not working)

Cost: $250-$600 Time: 1-3 days

If a new battery doesn’t help, the fob may have internal damage (water intrusion, cracked circuit board, worn buttons). Replacement typically involves buying an OEM fob and having it programmed to the vehicle.

âś“ Pros:
  • Restores like-new reliability
  • Best option if the original fob is physically damaged
âś— Cons:
  • More expensive than a battery
  • May require proof of ownership and an appointment for programming

⚠️ What to Avoid

✕ Don’t force the fob open with a large screwdriver—use gentle pressure and a suitable plastic pry tool to avoid breaking clips or the case.

✕ Don’t touch the new coin-cell battery surfaces excessively; oils and grime can reduce contact quality. Handle by the edges when possible.

✕ Don’t assume the car is dead: a dead fob battery can look like a vehicle battery problem. Try the backup start method before calling for a tow.

Frequently Asked Questions

How do I start my 2024 Hyundai Kona if the key fob battery is dead?

Use the backup detection method: press the brake and hold the fob directly against (or extremely close to) the START/STOP button, then press START. The vehicle can read the fob’s transponder at close range even when the fob battery is weak or dead.

What battery does the 2024 Hyundai Kona key fob use?

Many Hyundai smart key fobs use a CR2032 coin-cell, but there are variations. Check your owner’s manual or the marking on the old battery once opened to confirm the exact type before buying replacements.

Will I lose my settings or need to reprogram the key after changing the battery?

Typically, no. Replacing the coin-cell battery does not usually erase programming. If the fob still won’t work after a correct battery replacement, the issue may be the fob itself, a vehicle-side problem, or interference.

Why does the Kona say “Key not detected” even when the fob is inside?

A weak/dead fob battery is the most common cause. It can also happen if the fob is in a bag with metal objects, near strong RF interference, or if the fob has internal damage. Try the backup start method and replace the battery first.

⏱️ Urgency Note: Moderate urgency: you can usually still unlock and start the Kona using the mechanical key and backup detection, but replace the fob battery soon to avoid being locked out or stranded at an inconvenient time.

Related Information

Need Detailed Information?

Get vehicle-specific key fob compatibility, part numbers, and a complete price comparison for your 2024 Hyundai Kona.

View Kona Key Fob Guide →

Last updated: 2026-01-04