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2024 Acura RDX Key Fob Not Working: Quick Fixes, Causes, and Repair Options

If your 2024 Acura RDX key fob suddenly won’t lock/unlock or the vehicle won’t detect it for push-button start, the cause is usually power, signal interference, or a fob/vehicle receiver issue. The good news: you can often get back on the road with a few quick checks and Acura’s built-in backup starting method.

Understanding Your Situation

The RDX uses a smart key (proximity) system: the fob sends a low-power radio signal to the vehicle for locking/unlocking and starting. When the fob battery is weak, the signal is blocked (interference), or the fob/vehicle antenna system has a fault, the car may not respond or may display a “Keyless Access System Problem” or “Key Not Detected” message.

🚀 Immediate Steps to Take

  1. Try the spare key fob (if available). If the spare works, the issue is likely the original fob battery or the fob itself.
  2. Replace the key fob battery with a quality new coin cell (match the exact battery type printed in the fob). After replacement, test lock/unlock and remote functions from a few feet away.
  3. If the vehicle won’t start, use the emergency start method: hold the fob directly against/very close to the START/STOP button and press the brake, then press START. This uses the fob’s passive transponder even if the battery is weak.

Your Options

Replace the key fob battery (DIY)

Cost: $3-$12 Time: Same day

Open the fob case and install a new coin-cell battery of the correct type (as labeled inside the fob or in the owner’s manual). This addresses the most common cause: a weak or dead battery.

âś“ Pros:
  • Fastest and cheapest fix
  • Often restores both remote and proximity functions
âś— Cons:
  • Doesn’t help if the fob is damaged or the vehicle has a receiver/antenna issue
  • Improper installation can damage clips or cause intermittent contact

Use the backup start method and schedule service

Cost: $0-$50 Time: Same day

If the car won’t detect the key, start the RDX by holding the fob near the START/STOP button, then drive to a safe location or service facility. This is a workaround while you diagnose the fob or vehicle issue.

âś“ Pros:
  • Gets you moving even when the fob battery is weak
  • Buys time to troubleshoot without towing
âś— Cons:
  • May not restore lock/unlock range
  • If the fob is failing, the problem can worsen unpredictably

Dealer diagnostics and keyless system check

Cost: $150-$250 Time: Same day / 1-3 days

An Acura dealer can scan for body control/keyless access fault codes, verify antenna/receiver operation, and confirm whether the issue is the fob, keyless access module, or wiring/interference.

âś“ Pros:
  • Most accurate way to pinpoint vehicle-side faults
  • May be covered under warranty depending on cause and coverage
âś— Cons:
  • Higher upfront cost than DIY steps
  • Appointment availability may delay repair

Replace and program a new OEM smart key fob

Cost: $300-$650 Time: Same day / 1-3 days

If the fob is lost, water-damaged, or internally failed, an OEM replacement can be programmed to the vehicle. Programming typically requires dealer-level equipment and may require proof of ownership.

âś“ Pros:
  • Restores full factory function and reliability
  • Best compatibility and range compared to many aftermarket fobs
âś— Cons:
  • Most expensive common fix
  • Vehicle may need to be present for programming

⚠️ What to Avoid

✕ Don’t keep pressing the fob repeatedly for minutes—some vehicles temporarily reduce responsiveness after repeated attempts and it can mask the real issue (battery/interference).

✕ Don’t use the wrong coin-cell battery size or mix old/new batteries; poor contact can cause intermittent “Key Not Detected” problems.

✕ Don’t attempt to bypass or modify the keyless system wiring or antennas—improper repairs can cause no-start conditions and may affect warranty coverage.

⚠️ Common Mistakes to Avoid

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

Frequently Asked Questions

My 2024 Acura RDX says “Key Not Detected.” Will it still start?

Often yes. If the fob battery is weak, you can usually start the RDX by holding the fob directly against/very close to the START/STOP button while pressing the brake, then pressing START. If it still won’t start, the issue may be a failed fob, interference, or a vehicle-side keyless access fault.

Why does my key fob work sometimes but not others?

Intermittent operation is commonly caused by a weak battery, poor battery contact inside the fob, radio interference (parking garages, airports, dense electronics), or fob damage from drops/moisture. Try a fresh battery first and test in a different location away from other transmitters.

Could my phone or other electronics block the RDX key fob signal?

Yes. Phones, RFID wallets, other key fobs, and metal objects in the same pocket/bag can reduce range or prevent detection. Separate the fob from other electronics and try again.

If the spare fob works, does that confirm it’s not the car?

It strongly suggests the vehicle’s keyless system is functioning and the problem is with the original fob (battery, internal damage, or desynchronization). However, if both fobs fail in the same place, interference is also likely.

⏱️ Urgency Note: If the RDX won’t recognize any key fob and you can’t start it using the backup start method, treat it as urgent—avoid getting stranded and consider roadside assistance or towing to an Acura dealer. If you see a persistent “Keyless Access System Problem” warning, schedule service soon to prevent a future no-start.

Related Information

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Last updated: 2026-01-04