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2024 Kia K5 Dead Key Fob Battery (US): How to Get Back In and Start

A dead key fob battery on a 2024 Kia K5 can leave you unable to unlock the doors remotely or get the car to recognize the fob. The good news: you can still unlock the door with the hidden mechanical key and start the vehicle using the built-in backup detection method.

Understanding Your Situation

The small coin-cell battery inside the Kia Smart Key has discharged, so the fob’s buttons and normal proximity functions may stop working or become intermittent. The fob itself is usually fine—replacing the battery typically restores normal operation.

🚀 Immediate Steps to Take

  1. Unlock the door with the hidden mechanical key: slide the release on the fob to remove the emergency key, then use the driver-door key cylinder (remove the small cover if equipped) to unlock.
  2. Start the car using the backup method: with the fob inside the vehicle, use the vehicle’s designated backup key-fob detection location (commonly the START/STOP button area). Press the brake and attempt to start; if needed, hold the fob directly against the START/STOP button while pressing it.
  3. Replace the fob battery as soon as possible: install a new coin-cell battery (commonly CR2032 on many Kia smart keys—confirm by checking the old battery marking or your owner’s manual), then test lock/unlock and starting.

Your Options

DIY key fob battery replacement (recommended first step)

Cost: $3-$12 Time: Same day

Open the smart key case, swap the coin-cell battery for a new one (match the exact type printed on the old battery), and reassemble. No programming is typically required for a battery change.

âś“ Pros:
  • Fast and inexpensive
  • Usually restores full fob range immediately
âś— Cons:
  • You can crack the case or damage clips if pried incorrectly
  • Wrong battery type or reversed polarity will prevent operation

Battery replacement at a parts store or locksmith

Cost: $10-$30 Time: Same day

A store or locksmith replaces the coin-cell battery and may do a quick function check (lock/unlock/start).

âś“ Pros:
  • Less risk of breaking the fob housing
  • Quick confirmation that the issue is truly the battery
âś— Cons:
  • More expensive than DIY
  • Availability varies by location and time

Dealer inspection (if battery replacement doesn’t fix it)

Cost: $0-$200+ (diagnosis varies); $250-$600+ if a new smart key is needed Time: Same day / 1-3 days

Dealer checks for fob damage, vehicle antenna/receiver issues, or a weak 12V vehicle battery that can mimic fob problems. They can also replace the smart key shell or supply a new OEM key if needed.

âś“ Pros:
  • Most accurate diagnosis for persistent issues
  • OEM parts and support
âś— Cons:
  • Highest cost route if a new key is required
  • May require appointment and proof of ownership

⚠️ What to Avoid

✕ Don’t force the fob case open with excessive pressure—broken tabs can prevent the fob from sealing properly and can lead to future failures.

✕ Don’t install a different battery size/chemistry “that fits”—use the exact type printed on the old battery and confirm polarity (+/-) orientation.

✕ Don’t ignore repeated low-fob-battery warnings for weeks—once the battery is fully dead, you may be stuck using the mechanical key and backup start method.

⚠️ Common Mistakes to Avoid

  • Using wrong battery type
  • Damaging case during opening
  • Not resetting after replacement
  • Buying expensive batteries

Frequently Asked Questions

Can I start my 2024 Kia K5 if the key fob battery is dead?

Usually, yes. Use the mechanical key to get in if needed, then use the vehicle’s backup key-fob detection method—commonly holding the fob against/near the START/STOP button while pressing it with the brake pedal depressed. Exact behavior can vary by trim; your owner’s manual shows the backup start procedure.

What battery does a 2024 Kia K5 key fob use?

Many Kia smart keys use a CR2032 coin-cell, but you should confirm by reading the battery code printed on the old battery or checking the owner’s manual for your specific trim/fob style. Replace it with the exact same type.

Will I need to reprogram the key fob after replacing the battery?

Normally, no. A battery swap should not erase programming. If the fob still won’t work after a correct battery installation, the fob may be damaged, the battery may be installed incorrectly, or the vehicle could have a separate issue (including a weak 12V battery).

Why does my fob work only when I’m very close to the car?

That’s a classic sign of a weak coin-cell battery. Range drops first, then buttons/proximity become intermittent, and eventually the fob stops working. Replace the battery and retest.

⏱️ Urgency Note: Low immediate safety risk, but moderate urgency for convenience and reliability. Replace the fob battery soon—especially before travel—so you’re not forced to use the mechanical key and backup start method unexpectedly.

Related Information

Need Detailed Information?

Get vehicle-specific key fob compatibility, part numbers, and a complete price comparison for your 2024 Kia K5.

View K5 Key Fob Guide →

Last updated: 2026-01-04