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2023 Toyota Corolla Key Fob Not Working: Quick Fixes, Causes, and Repair Options

If your 2023 Toyota Corolla key fob suddenly won’t lock/unlock or won’t start the car, the cause is often a weak fob battery or signal interference. The good news: you can usually get into the car and start it using Toyota’s backup procedures while you troubleshoot.

Understanding Your Situation

On the 2023 Corolla (US), the smart key/remote system relies on a small coin-cell battery, a working transmitter, and the car’s receiver/immobilizer authorization. When the fob battery is low, the fob is damaged, or the signal is blocked, the car may not respond to button presses and may show “Key Not Detected” when trying to start.

🚀 Immediate Steps to Take

  1. Try the mechanical key: Press the release on the fob to pull out the hidden metal key and unlock the driver door manually.
  2. Use the backup start method: Hold the Toyota emblem side of the fob against the START/STOP button (or follow the dash prompt), then press the brake and press START/STOP to start the car.
  3. Replace the fob battery and retest: Install a fresh CR2032 (common for Toyota smart keys), confirm correct polarity, then test lock/unlock and starting from outside the vehicle.

Your Options

Replace the key fob battery (DIY)

Cost: $3-$15 Time: Same day (10-20 minutes)

Open the fob case carefully, replace the coin-cell battery (commonly CR2032), and verify the buttons and smart key function return. This fixes most sudden “not working” issues caused by low voltage.

âś“ Pros:
  • Lowest cost and fastest fix
  • Often restores both remote buttons and push-button start detection
âś— Cons:
  • Opening the case improperly can crack the shell
  • If the fob is damaged or unprogrammed, a battery won’t help

Rule out interference / vehicle-side issues

Cost: $0-$60 Time: Same day

Test with the spare fob (if available), move away from potential RF interference (parking garages, cell towers, metal structures), and check for a weak 12V battery if the car behaves oddly (slow electronics, multiple warning lights).

âś“ Pros:
  • Can identify whether the problem is the fob or the car
  • Avoids unnecessary key replacement
âś— Cons:
  • Intermittent issues can be hard to reproduce
  • 12V battery testing may require a shop visit if you don’t have tools

Repair or replace the key fob shell/buttons

Cost: $20-$120 Time: Same day / 1-3 days

If the fob works intermittently or only at very close range, the internal board may be fine but the case, buttons, or battery contacts may be worn or damaged. A locksmith can often transfer the internal electronics into a new shell.

âś“ Pros:
  • Cheaper than full key replacement when electronics are still good
  • Restores reliable button feel and battery contact
âś— Cons:
  • Not a fix if the transmitter board is failing
  • Quality varies by parts source

Replace and program a new smart key fob (locksmith or dealer)

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

Purchase a compatible smart key fob and have it programmed to your Corolla’s immobilizer/smart key system. This is the typical solution if the fob is lost, water-damaged, or electronically failed.

âś“ Pros:
  • Restores full functionality with a reliable, matched key
  • A pro can also delete lost keys from the vehicle (when possible)
âś— Cons:
  • Higher cost (fob + programming)
  • May require proof of ownership and an appointment

Dealer diagnosis for smart key/immobilizer faults

Cost: $150-$250 (diagnosis) + repairs Time: Same day / 1-3 days

If neither fob works and a new battery doesn’t help, the issue may be with the vehicle (smart key ECU/receiver, wiring, or related modules). A Toyota dealer can scan for codes and confirm the failure point.

âś“ Pros:
  • Most accurate troubleshooting for vehicle-side problems
  • OEM parts and procedures
âś— Cons:
  • Diagnosis fees may apply even if you decline repairs
  • Repairs can be costly if modules are involved

⚠️ What to Avoid

✕ Don’t force the fob open with excessive prying—broken clips and cracked shells are common and can cause battery contact issues.

✕ Don’t buy the cheapest online fob without verifying compatibility (FCC ID/part number); mismatched fobs may not program or may have limited functions.

✕ Don’t ignore signs of a weak 12V battery (slow cranking on non-hybrid models, dim lights, repeated warnings); low vehicle voltage can mimic key problems.

⚠️ 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 my 2023 Corolla if it says “Key Not Detected”?

Use the backup method: press the brake, hold the Toyota emblem side of the fob against the START/STOP button (or follow the on-screen prompt), then press START/STOP. This allows the car to read the fob even if the fob battery is weak.

What battery does a 2023 Toyota Corolla key fob use?

Many 2023 Corolla smart keys use a CR2032 coin-cell, but verify by opening the fob and reading the battery marking (or check your owner’s manual). Install with the correct polarity and avoid touching both sides of the new battery with bare fingers if possible.

My buttons don’t work, but the car still starts. What does that mean?

That commonly points to a weak fob battery or worn button contacts. The passive RFID-style backup/start detection can still work at close range even when the remote transmitter for lock/unlock is failing.

Will disconnecting the car battery fix a key fob that stopped working?

Usually no. A dead or weak 12V battery can cause smart key issues, but disconnecting power is not a reliable fix and can reset settings. It’s better to test the 12V battery and address the root cause.

Can a locksmith program a 2023 Corolla smart key, or do I need the dealer?

Many automotive locksmiths can program Toyota smart keys, but capability varies by equipment and vehicle configuration. If all keys are lost or there’s an immobilizer-related issue, the dealer may be required.

⏱️ Urgency Note: If you’re stranded or the fob works intermittently, address it soon—especially before you’re away from home. If you only have one working key, consider getting a spare programmed now to avoid a more expensive all-keys-lost situation later.

Related Information

Need Detailed Information?

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

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Last updated: 2026-01-04