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2023 Toyota Highlander Key Fob Not Working? Quick Fixes & Next Steps (US)

If your 2023 Toyota Highlander key fob suddenly won’t lock/unlock the doors or won’t let the vehicle start, the cause is often a weak fob battery or a communication issue. The good news: you can usually get back on the road using Toyota’s backup entry and start methods while you troubleshoot.

Understanding Your Situation

Most “key fob not working” cases come from a depleted CR2032 battery, a fob that got wet or damaged, radio interference, or a vehicle-side issue (12V battery low, antenna/module fault). Even if the buttons don’t work, the fob may still start the car using the Smart Key backup procedure.

🚀 Immediate Steps to Take

  1. Try the backup entry method: press the small release on the fob to remove the mechanical key, then unlock the driver door with the key blade (alarm may sound until you start the car).
  2. Try the backup start method (push-button start models): hold the fob directly against the START/STOP button (logo-side toward the button) and press the brake, then press START. This uses the fob’s passive transponder even if the battery is weak.
  3. Replace the key fob battery (typically CR2032). After replacement, test LOCK/UNLOCK and remote start (if equipped). If it still fails, try your spare fob to isolate whether it’s a fob or vehicle issue.

Your Options

Replace the key fob battery (DIY)

Cost: $3-$15 Time: Same day

Open the fob case, replace the CR2032 coin-cell battery, and verify all functions. Inspect for corrosion or moisture inside the fob while it’s open.

✓ Pros:
  • Fast and inexpensive
  • Fixes the most common cause
  • No programming required for a simple battery swap
✗ Cons:
  • Won’t help if the fob is water-damaged or internally broken
  • Incorrect battery orientation or pinched seals can cause repeat issues

Use the spare key fob and diagnose the original

Cost: $0-$15 Time: Same day

Test a second working fob to confirm the vehicle is responding. If the spare works, the original fob likely needs repair, a battery, or replacement.

✓ Pros:
  • Quick way to pinpoint fob vs vehicle problem
  • Helps avoid unnecessary towing or dealer visits
✗ Cons:
  • Not possible if you don’t have a spare
  • If both fobs fail, the issue may be vehicle-side

Re-sync/relearn by cycling power (basic reset)

Cost: $0-$250 Time: Same day

Address temporary glitches by turning the vehicle fully off, moving away from the car with the fob for a minute, then retrying. If the vehicle’s 12V battery is weak, charging/testing it may restore Smart Key reliability.

✓ Pros:
  • Can resolve intermittent communication issues
  • A 12V battery test can prevent future no-starts
✗ Cons:
  • Not a guaranteed fix for a failed fob
  • 12V battery replacement adds cost if needed

Dealer diagnosis and key fob replacement/programming

Cost: $250-$650 Time: Same day / 1-3 days

Toyota dealer verifies Smart Key system operation, checks for stored fault codes, and replaces/programs a new OEM fob if the original is defective or missing.

✓ Pros:
  • OEM parts and correct programming
  • Vehicle-side issues can be diagnosed properly
  • Warranty coverage may apply depending on cause and coverage status
✗ Cons:
  • Higher cost than DIY or locksmith options
  • May require appointment and proof of ownership

Automotive locksmith (mobile) key fob replacement/programming

Cost: $180-$450 Time: Same day

A qualified mobile locksmith supplies and programs a compatible fob on-site. They can also cut a mechanical key if needed.

✓ Pros:
  • Often faster than a dealer and can come to you
  • Can be less expensive than OEM dealer pricing
✗ Cons:
  • Quality varies—use a licensed/insured locksmith with Toyota experience
  • Aftermarket fobs may have reduced range or feature limitations

⚠️ What to Avoid

✕ Don’t force the fob case open with sharp tools that can crack the shell, damage the circuit board, or compromise water resistance.

✕ Don’t keep pressing the start button repeatedly if the car won’t recognize the key—use the backup start method (touch fob to button) and then troubleshoot calmly.

✕ Don’t assume it’s only the fob: if both fobs act up, have the vehicle’s 12V battery tested before paying for programming or towing.

⚠️ Common Mistakes to Avoid

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

Frequently Asked Questions

My 2023 Highlander won’t unlock with the fob—how do I get in?

Remove the mechanical key blade from the fob (using the release on the fob) and unlock the driver door manually. If the alarm sounds, it typically stops once the vehicle recognizes a valid key and you start it.

If the key fob battery is dead, can I still start the Highlander?

Usually yes. For push-button start, hold the fob against the START/STOP button and press the brake, then press START. This allows the vehicle to read the fob’s passive transponder even with a weak/dead fob battery.

What battery does a 2023 Toyota Highlander key fob use?

Most 2023 Highlander smart key fobs use a CR2032 coin-cell battery, but confirm by checking the marking on the old battery or your owner’s manual.

Why does my key fob work sometimes and not others?

Intermittent operation is commonly caused by a weakening fob battery, moisture damage, or radio interference (parking garages, dense urban areas, or nearby transmitters). It can also happen when the vehicle’s 12V battery is low.

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

Typically no—battery replacement alone shouldn’t erase programming. If it still doesn’t work after a new battery, the fob may be damaged or the vehicle may have a Smart Key system issue that needs diagnosis.

⏱️ Urgency Note: If you’re stranded or the vehicle won’t start even with the fob held to the START/STOP button, treat it as urgent—avoid repeated attempts that can drain the 12V battery further. If the 12V battery is weak or the car is in an unsafe location, arrange roadside assistance or towing to a safe place for diagnosis.

Related Information

Need Detailed Information?

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

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Last updated: 2026-01-04