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Dead Key Fob Battery (2023 Hyundai Tucson): How to Unlock & Start Your SUV

If your 2023 Hyundai Tucson key fob suddenly won’t unlock the doors or the push-button start won’t respond, the most common cause is a dead fob battery. The good news: you can still get in and start the vehicle, then replace the battery in minutes.

Understanding Your Situation

The coin-cell battery inside the Tucson smart key can no longer provide enough power to transmit a signal to the vehicle. The mechanical key inside the fob still works for the door, and the vehicle has a built-in backup method to recognize the fob for starting.

🚀 Immediate Steps to Take

  1. Unlock the driver’s door with the hidden mechanical key: press the release on the fob to pull out the metal key, then use the key cylinder (typically hidden behind a small cover on the driver door handle).
  2. Start the Tucson using the backup method: hold the Hyundai logo side of the fob against the START/STOP button (or place it directly next to the button) and press the brake, then press START/STOP while the fob is touching the button.
  3. Replace the fob battery as soon as possible (commonly a CR2032 coin cell for this model) and test lock/unlock, remote start (if equipped), and proximity functions.

Your Options

DIY key fob battery replacement (most common fix)

Cost: $3-$12 Time: Same day

Buy a new coin-cell battery (often CR2032) and install it in the smart key. Open the fob carefully at the seam, swap the battery with the correct polarity, and reassemble.

âś“ Pros:
  • Lowest cost solution
  • Usually restores full fob range and reliability immediately
âś— Cons:
  • Risk of damaging the fob housing if pried aggressively
  • Using a low-quality battery can lead to short life or inconsistent performance

Battery replacement at a parts store or locksmith

Cost: $10-$30 Time: Same day

Have a professional replace the coin cell and confirm the fob works afterward. Some shops will also inspect the fob case and contacts for damage or corrosion.

âś“ Pros:
  • Quick and convenient with less chance of breaking the fob
  • Often includes a basic function check
âś— Cons:
  • Costs more than DIY
  • Quality can vary by shop (battery brand and handling)

Dealer service visit (if problems continue after a new battery)

Cost: $0-$200+ Time: 1-3 days

If a new battery doesn’t fix it, the dealer can test the smart key, check for vehicle-side issues (antenna/receiver, door handle sensors), and verify software updates or fault codes.

âś“ Pros:
  • Best option for diagnosing vehicle-side communication issues
  • May be covered under warranty depending on the cause
âś— Cons:
  • Higher potential cost if not warranty-related
  • May require an appointment and wait time

⚠️ What to Avoid

✕ Don’t assume the fob is “dead” and order a new one before trying a fresh coin-cell battery—battery failure is far more common than fob failure.

✕ Don’t pry the fob open with excessive force or metal tools that can crack the case or damage the circuit board; use gentle pressure at the seam.

✕ Don’t install the battery upside down or touch both battery faces with greasy/dirty fingers—poor contact can cause intermittent operation.

⚠️ Common Mistakes to Avoid

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

Frequently Asked Questions

Can I still start my 2023 Hyundai Tucson if the key fob battery is dead?

Yes. Use the backup start method: hold the fob against the START/STOP button and press the brake, then press START/STOP while the fob is touching the button so the vehicle can read the transponder.

What battery does a 2023 Hyundai Tucson key fob use?

Most 2023 Tucson smart keys use a CR2032 coin-cell battery, but verify by opening the fob and matching the number printed on the old battery.

How do I unlock the door if the fob won’t work?

Slide the release on the fob to remove the hidden mechanical key, then unlock the driver’s door using the key cylinder (often behind a small cover on the driver door handle).

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

Typically no. Replacing the coin-cell battery should not erase programming; the fob should work immediately once reassembled correctly.

⏱️ Urgency Note: Low to moderate urgency: you can usually unlock and start the Tucson using the mechanical key and backup start method, but replace the battery soon to avoid being locked out at an inconvenient time.

Related Information

Need Detailed Information?

Get vehicle-specific key fob compatibility, part numbers, and a complete price comparison for your 2023 Hyundai Tucson.

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Last updated: 2026-01-04