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2024 Toyota Highlander Dead Key Fob Battery: How to Get In, Start, and Replace It

If your 2024 Toyota Highlander key fob suddenly won’t unlock the doors or the vehicle won’t detect the fob, the most common cause is a depleted fob battery. The good news: you can still get in and start the vehicle, then replace the battery quickly.

Understanding Your Situation

The coin-cell battery inside the Highlander’s smart key fob has dropped too low to reliably power the fob’s radio signal, so the vehicle may not sense the fob for keyless entry or push-button start. This often appears as reduced range, intermittent unlocking, or a “Key Not Detected” message.

🚀 Immediate Steps to Take

  1. Use the hidden mechanical key to unlock the driver’s door (slide the release on the fob to remove the key, then insert it into the driver door key cylinder—usually behind a small cover).
  2. Start the Highlander using the fob’s emergency start method: hold the fob against the START/STOP button (Toyota logo side typically facing the button) and press the brake, then press START/STOP.
  3. Replace the fob battery with a new coin cell (commonly CR2032 for many Toyota smart keys—confirm the exact type printed on your old battery), then test lock/unlock and remote range.

Your Options

DIY battery replacement (most common)

Cost: $3-$10 Time: Same day

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

âś“ Pros:
  • Fast and inexpensive
  • Usually restores full range immediately
âś— Cons:
  • Easy to damage the case or seal if pried incorrectly
  • Wrong battery type or upside-down installation can mimic a bigger problem

Replace battery at a Toyota dealer or service shop

Cost: $0-$25 Time: Same day

A dealer or repair shop replaces the fob battery for you and can verify the fob is communicating properly afterward.

âś“ Pros:
  • Reduces risk of breaking the fob housing
  • Quick confirmation if the issue is battery-related
âś— Cons:
  • May require a trip/appointment
  • Some locations charge a minimum fee

Mobile locksmith battery swap + key fob health check

Cost: $50-$150 Time: Same day

A mobile automotive locksmith comes to you, replaces the battery, and can help diagnose if the fob itself is failing or if there’s a vehicle-side issue.

âś“ Pros:
  • Convenient if you’re stranded
  • Can diagnose beyond just the battery
âś— Cons:
  • Higher cost than DIY
  • Quality varies—use a reputable, licensed provider

⚠️ What to Avoid

✕ Forcing the fob open with a knife or metal tool that can crack the housing or damage internal components—use a plastic pry tool if possible.

âś• Installing a different battery size/chemistry than the one printed on the original battery (or installing it upside down).

✕ Assuming the fob is “dead” and ordering a new one before trying the emergency start method and a fresh battery—replacement keys are far more expensive.

⚠️ 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 2024 Toyota Highlander if the key fob battery is dead?

Yes. Use the emergency start method: press the brake and hold the fob against the START/STOP button, then press START/STOP. The vehicle can read the fob at very close range even when the battery is depleted.

What battery does the 2024 Toyota Highlander key fob use?

Many Toyota smart keys use a CR2032 coin-cell battery, but you should confirm by checking the battery type printed on the old battery inside your fob or your owner’s manual for your exact trim/fob style.

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

Typically, no. A battery replacement should not erase programming. If the fob still doesn’t work after a correct battery install, the fob may be damaged, the battery may be weak/defective, or there may be a vehicle-side issue.

Why did my range get worse before it stopped working?

A weakening coin-cell battery often causes reduced signal strength first—so you may need to be closer to the vehicle—before it fails enough to trigger “Key Not Detected” or prevent remote locking/unlocking.

⏱️ Urgency Note: Low to moderate urgency: it’s usually safe to drive once started, but replace the battery soon so you don’t get stranded somewhere you can’t easily unlock or start the vehicle. If you only have one working fob, replace the battery proactively and keep a spare coin cell in the vehicle.

Related Information

Need Detailed Information?

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

View Highlander Key Fob Guide →

Last updated: 2026-01-04