Key Fob Not Working high urgency

2024 Hyundai Elantra Key Fob Not Working: Quick Fixes, Costs, and Next Steps

If your 2024 Hyundai Elantra key fob suddenly won’t lock/unlock or won’t start the car, the cause is usually a weak fob battery, interference, or a fob/vehicle communication issue. The good news: you can often regain access and start the car using built-in backup methods while you troubleshoot.

Understanding Your Situation

The key fob may not be sending a strong signal (commonly due to a low battery), the vehicle may not be receiving it (interference or receiver issue), or the fob may be damaged/desynced. In some cases, the car’s 12V battery is weak, which can prevent the smart key system from responding.

🚀 Immediate Steps to Take

  1. Try the backup entry method: press the release on the fob to remove the hidden mechanical key, then unlock the driver’s door using the key cylinder (typically behind a small cover on the handle).
  2. Try the backup start method (push-button start models): hold the fob directly against/near the START/STOP button and press the brake, then press START. This can work even with a weak fob battery.
  3. Rule out simple causes: move away from potential interference (other key fobs, wireless devices), try your spare fob if available, and check whether the car’s 12V battery seems weak (dim lights, slow electronics).

Your Options

Replace the key fob battery (DIY)

Cost: $3-$15 Time: Same day

Open the fob case and replace the coin-cell battery with the correct type (commonly CR2032 on many Hyundai fobs, but verify your exact fob). Then test lock/unlock and starting functions.

âś“ Pros:
  • Lowest-cost fix for the most common cause
  • No programming typically needed for a simple battery swap
âś— Cons:
  • Wrong battery type or poor contact can keep the fob from working
  • Doesn’t help if the fob is damaged or the vehicle has a receiver/12V issue

Use the spare key fob and diagnose the original

Cost: $0-$15 Time: Same day

If your spare fob works, the issue is likely with the original fob (battery, internal damage, or worn buttons). You can then replace the battery, inspect for water damage, or replace the fob.

âś“ Pros:
  • Fast way to isolate whether the problem is the car or the fob
  • May avoid towing or dealer visit
âś— Cons:
  • Not possible if you don’t have a spare
  • Spare may also be low battery if rarely used

Check/charge or replace the vehicle 12V battery

Cost: $0-$250 Time: Same day

If the Elantra’s 12V battery is weak, the smart key system may not respond reliably. A jump start, battery test, or replacement may restore normal operation.

âś“ Pros:
  • Fixes a vehicle-side cause that can mimic a bad key fob
  • Improves overall reliability (starting, electronics, safety systems)
âś— Cons:
  • Requires tools or roadside assistance
  • If the 12V battery is fine, this won’t resolve a fob issue

Replace and program a new OEM key fob (dealer)

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

The dealer supplies an OEM smart key fob and programs it to your Elantra. This is the most reliable route if the fob is lost, damaged, or not communicating properly.

âś“ Pros:
  • Highest compatibility and reliability
  • Programming and verification handled by trained technicians
âś— Cons:
  • Higher cost than other options
  • May require appointment, proof of ownership, and waiting for parts

Mobile automotive locksmith (smart key replacement/programming)

Cost: $180-$450 Time: Same day

A qualified locksmith can often supply and program a compatible smart key fob at your location. This is helpful if the car won’t start or you’re stranded.

âś“ Pros:
  • Convenient on-site service (often faster than a dealer)
  • Can be cheaper than dealer OEM in many cases
âś— Cons:
  • Quality varies—must confirm experience with Hyundai smart keys
  • Some aftermarket fobs may have reduced range or features

⚠️ What to Avoid

✕ Don’t force the fob open with sharp tools that can crack the housing or damage the circuit board—use a proper pry point and gentle pressure.

✕ Don’t repeatedly press the START/STOP button without following the backup start method (fob against the button); it can drain the fob battery further and waste time.

✕ Don’t assume it’s the fob if the car shows signs of a weak 12V battery (dim interior lights, erratic electronics)—address the 12V system first for safety and reliability.

⚠️ Common Mistakes to Avoid

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

Frequently Asked Questions

How do I start a 2024 Hyundai Elantra if the key fob battery is dead?

If your Elantra has push-button start, hold the fob directly against/near the START/STOP button and press the brake, then press START. This backup method can work even when the fob battery is too weak for normal operation. Use the hidden mechanical key to unlock the driver’s door if needed.

What battery does a 2024 Hyundai Elantra key fob use?

Many Hyundai smart key fobs use a CR2032 coin-cell battery, but it can vary by fob design and trim. Confirm by checking the old battery marking after opening the fob or by referencing your owner’s manual.

My key fob locks/unlocks but won’t start the car—what does that mean?

It can indicate the fob isn’t being detected inside the cabin (weak fob battery, interference, or a detection/antenna issue). Try the backup start method by holding the fob against/near the START/STOP button. If it still won’t start, have the 12V battery and the smart key system checked.

Will replacing the key fob battery erase programming or require reprogramming?

Typically, no. A battery replacement should not erase the fob’s programming. If the fob still doesn’t work after a correct battery install, the issue may be poor battery contact, internal fob damage, or a vehicle-side problem.

Why does my key fob work only sometimes or only at very close range?

This is commonly a weak coin-cell battery, but it can also be radio interference (parking garages, dense urban areas), a damaged fob, or a vehicle receiver issue. Replace the fob battery first, then test in a different location and with the spare fob.

Do I need to tow the car to the dealer if the key fob isn’t working?

Not always. If you can unlock with the mechanical key and start using the backup start method, you may be able to drive to a dealer or locksmith. If the car won’t power on or the 12V battery is dead and you can’t jump it safely, roadside assistance may be the safest choice.

⏱️ Urgency Note: If you’re locked out, stranded, or the car won’t start in an unsafe location, treat this as urgent—use the mechanical key/backup start method and consider roadside assistance. If the issue is intermittent, address it soon to avoid a complete no-start situation.

Related Information

Need Detailed Information?

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

View Elantra Key Fob Guide →

Last updated: 2026-01-04