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2024 Hyundai Santa Fe Key Fob Not Working (US): Quick Fixes & Next Steps

If your 2024 Hyundai Santa Fe key fob suddenly won’t lock/unlock or the vehicle won’t detect it, the cause is often a weak fob battery or a communication issue. The good news: you can usually get back in and start the SUV using the built-in backup methods, then decide whether you need a new battery, a replacement fob, or service.

Understanding Your Situation

The Santa Fe uses a proximity “smart key” system. When the fob battery is low, the fob is damaged, or there’s radio interference, the vehicle may not receive a strong enough signal to unlock doors or allow push-button start.

🚀 Immediate Steps to Take

  1. Try the backup entry method: remove the mechanical key from the fob (release latch on the fob) and unlock the driver’s door using the hidden key cylinder (often behind a small cover on the handle).
  2. Try the backup start method: with the fob inside the vehicle, press the START/STOP button while holding the fob very close to the button area (or where the owner’s manual indicates the emergency detection point). Press the brake and try again.
  3. Replace the fob battery (commonly a CR2032 coin cell, but confirm by opening the fob or checking the manual). Install with correct polarity, then test lock/unlock and starting.

Your Options

Replace the key fob battery (DIY or parts counter)

Cost: $3-$15 Time: Same day

Open the fob case carefully, replace the coin-cell battery with a quality brand, and reassemble. This resolves most sudden “not working” issues.

âś“ Pros:
  • Lowest cost and fastest fix
  • No programming required for a simple battery swap
âś— Cons:
  • If the fob is damaged or the vehicle isn’t detecting any fob, a battery may not solve it
  • Opening the fob incorrectly can crack the housing or damage the seal

Use the Hyundai Digital Key (if equipped and previously set up)

Cost: $0-$20 Time: Same day

If your Santa Fe supports Digital Key and it was already paired to your phone, you may be able to lock/unlock and start using your smartphone until the fob is fixed.

âś“ Pros:
  • Can get you moving without waiting for parts
  • Useful as a backup even after the fob is repaired
âś— Cons:
  • Must be set up in advance on many vehicles
  • Phone battery, app/login issues, or cellular/Bluetooth problems can still prevent access

Inspect/clean the fob and rule out interference

Cost: $0-$50 Time: Same day

Check for water intrusion, cracks, or a stuck button. Move away from strong RF sources (parking garages, antennas, other key fobs pressed against yours). Try the spare fob if available to isolate whether the problem is the vehicle or the fob.

âś“ Pros:
  • Helps identify whether the issue is the fob, battery, or environment
  • May avoid unnecessary replacement or programming costs
âś— Cons:
  • Doesn’t fix internal fob failures
  • Intermittent issues can be difficult to reproduce

Dealer diagnosis and replacement smart key (OEM)

Cost: $250-$600+ Time: Same day to 1-3 days

A Hyundai dealer can test the fob and vehicle antennas, verify immobilizer/Smart Key system faults, and supply/program an OEM smart key if needed.

âś“ Pros:
  • Correct OEM part and proper programming
  • Access to Hyundai diagnostic tools and service bulletins
âś— Cons:
  • Typically the most expensive route
  • May require towing if you can’t start the vehicle

Automotive locksmith (mobile smart key service)

Cost: $180-$450 Time: Same day

A qualified locksmith can often cut an emergency key (if needed) and program a compatible smart key on-site. Ideal if you’re stranded or want a faster appointment than a dealer.

âś“ Pros:
  • Convenient mobile service
  • Often faster and sometimes cheaper than a dealer
âś— Cons:
  • Not all locksmiths support very new models immediately
  • Aftermarket fob quality can vary; confirm warranty and compatibility

⚠️ What to Avoid

✕ Don’t force the fob open with excessive prying—broken clips and damaged circuit boards are common when the wrong tool is used.

✕ Don’t keep pressing buttons repeatedly while standing next to the vehicle for long periods; it can drain a weak battery quickly and may trigger alarm behavior.

✕ Don’t assume it’s “just the car battery” and jump-start without checking basics first—if the fob isn’t being detected, you may still need the backup start method or a new fob battery.

⚠️ Common Mistakes to Avoid

  • Assuming key is broken
  • Not checking battery first
  • Calling tow truck immediately
  • Replacing when reprogramming needed

Frequently Asked Questions

My 2024 Santa Fe says “Key not detected.” Will it still start?

Often yes. If the fob battery is weak, use the backup start method by holding the fob close to the START/STOP button area (per the owner’s manual) while pressing the brake and starting. If it still won’t detect either fob, the issue may be the fob, interference, or the vehicle’s Smart Key system.

Do I need to reprogram the key fob after changing the battery?

Usually no. A battery replacement alone typically does not require reprogramming. If the fob still doesn’t work after a known-good battery is installed correctly, the fob may be damaged or desynchronized, or the vehicle may have a Smart Key/antenna issue that needs diagnosis.

What battery does the 2024 Hyundai Santa Fe key fob use?

Many Hyundai smart keys use a CR2032 coin-cell battery, but you should confirm by opening the fob or checking your owner’s manual because battery type can vary by fob design and trim.

If one fob works and the other doesn’t, what does that mean?

That usually points to a problem with the non-working fob (weak battery, water damage, worn buttons, or internal failure) rather than a vehicle-side issue. Replace the battery first, then consider fob replacement if it still fails.

⏱️ Urgency Note: Moderate urgency. If you’re locked out, use the mechanical key to enter safely and avoid damaging trim. If the vehicle won’t start and you’re in an unsafe location, contact roadside assistance or a mobile locksmith; repeated start attempts with a weak fob battery can leave you stranded.

Related Information

Need Detailed Information?

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Last updated: 2026-01-04