Dead Key Fob Battery medium urgency

Dead Key Fob Battery? How to Start & Unlock a 2024 Toyota Tundra (US)

A dead key fob battery on a 2024 Toyota Tundra can stop remote lock/unlock and may prevent push-button start from recognizing the fob. The good news: you can usually unlock the door with the hidden mechanical key and start the truck using the fob’s emergency start method. Then replace the fob battery to restore normal operation.

Understanding Your Situation

The coin-cell battery inside the Smart Key fob has discharged, so the fob can’t reliably transmit a signal to the truck. In many cases, the vehicle can still detect the fob at very close range using an emergency “touch/hold” procedure, even when the fob battery is too weak for normal use.

🚀 Immediate Steps to Take

  1. Unlock if needed: Slide the release on the fob to remove the hidden mechanical key, then use it in the driver’s door lock (there may be a small cover over the key cylinder).
  2. Start the truck (push-button start): Hold the Toyota emblem side of the fob directly against the START/STOP button, then press the brake and press the START/STOP button to start.
  3. Replace the fob battery ASAP: Install a fresh coin-cell battery (commonly CR2032 on many Toyota Smart Keys, but confirm by checking the battery marking inside your fob or your owner’s manual).

Your Options

DIY key fob battery replacement (most common fix)

Cost: $3-$15 Time: Same day

Open the Smart Key fob, note the battery orientation (+/-), replace with a new coin-cell battery, then reassemble and test lock/unlock and starting.

✓ Pros:
  • Lowest cost
  • Fast and widely available parts
✗ Cons:
  • Wrong battery type or flipped polarity can cause continued issues
  • Risk of damaging the fob case or seal if pried incorrectly

Replace battery at a dealer or independent shop

Cost: $10-$40 Time: Same day

A service advisor or technician replaces the fob battery and confirms the fob functions normally afterward.

✓ Pros:
  • Reduced risk of breaking the fob housing
  • Quick confirmation that the issue is truly the battery
✗ Cons:
  • More expensive than DIY
  • May require a visit during business hours

Mobile locksmith visit (if you’re stranded and need help now)

Cost: $75-$200 Time: Same day

A locksmith can help you gain entry, verify the fob/battery issue, and often replace the coin-cell battery on-site. If the fob is damaged, they can advise on replacement options.

✓ Pros:
  • Comes to you
  • Helpful if you can’t access the vehicle or need immediate assistance
✗ Cons:
  • Higher cost
  • Service availability varies by area and time

Key fob replacement (only if battery replacement doesn’t fix it)

Cost: $250-$600+ Time: 1-7 days

Purchase a new Toyota Smart Key fob and have it programmed to your 2024 Tundra. This is appropriate if the fob is water-damaged, physically broken, or not recognized even with a new battery.

✓ Pros:
  • Resolves failed or damaged fob hardware
  • Restores full Smart Key reliability
✗ Cons:
  • Most expensive option
  • May require appointment and proof of ownership

⚠️ What to Avoid

✕ Don’t force the fob open with excessive pressure or metal tools that can crack the housing or damage internal clips; use a gentle pry at the designated seam.

✕ Don’t use an unknown/old battery or touch the new battery surfaces excessively; oils and low-quality cells can shorten life or reduce reliability.

✕ Don’t assume it’s “just the battery” if the truck still won’t recognize the fob after replacement—water damage, a damaged fob, or vehicle-side issues can mimic a dead battery.

Frequently Asked Questions

How do I start my 2024 Toyota Tundra if the key fob battery is dead?

Use the emergency start method: hold the fob directly against the START/STOP button (Toyota emblem side toward the button), then press the brake and press START/STOP. This allows the truck to read the fob at very close range even when the battery is weak.

What battery does a 2024 Toyota Tundra key fob use?

Many Toyota Smart Key fobs use a CR2032 coin-cell, but you should confirm by opening the fob and reading the battery label (or checking your owner’s manual). Install the same type and match the correct +/− orientation.

Will a dead key fob battery prevent me from unlocking the door?

Remote buttons may not work, but you can still unlock the driver’s door using the hidden mechanical key stored inside the fob.

After replacing the battery, do I need to reprogram the fob?

Typically no. A simple battery swap should not erase programming. If the fob still doesn’t work, confirm battery orientation and try a different new battery; if problems continue, the fob may be damaged or the vehicle may need diagnosis.

⏱️ Urgency Note: Low to moderate urgency: You can usually unlock and start the truck using the mechanical key and emergency start method, but replace the battery soon to avoid being stranded later—especially in extreme heat/cold or if you only have one working fob.

Related Information

Need Detailed Information?

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

View Tundra Key Fob Guide →

Last updated: 2026-01-04