How Remote Locking on a Car Works

Remote locking uses a key fob or phone to send an encrypted radio signal that the car verifies before commanding its door actuators to lock or unlock; newer systems add hands-free “passive” entry, Bluetooth Low Energy, and ultra‑wideband ranging to improve convenience and security. In practice, a transmitter (fob or phone) and a receiver in the vehicle exchange time‑limited, cryptographically protected codes, the body control module authorizes the request, and the central locking hardware physically secures the doors while flashing lights or sounding a chirp to confirm.

The core idea

At its simplest, remote keyless entry is a secure radio conversation between your key and your car. The transmitter emits a signal on regulated frequencies (commonly 315 MHz in North America, 433.92/868 MHz in Europe, or 902–928 MHz in some regions; newer digital keys use 2.4 GHz Bluetooth LE and 6–8 GHz ultra‑wideband). The vehicle’s receiver checks that the message is authentic and fresh, then the body control module triggers lock actuators and logs the event. Hands‑free systems add low‑frequency antennas (around 125 kHz) and, increasingly, ultra‑wideband to verify the key is near the door and not being relayed from far away.

The hardware in play

Remote locking relies on several coordinated components inside the key fob/phone and the vehicle. Below are the typical pieces you’ll find in modern systems and what they do.

• Transmitter (key fob or smartphone): Sends commands via RF (fob buttons), BLE (phone key), or NFC for close‑range backup; powered by a coin cell or phone battery.
• Vehicle antennas and receivers: UHF antennas for classic fobs; low‑frequency (LF) antennas near door handles and cabin for passive entry; BLE/UWB radios for digital keys.
• Security and crypto chips: Implement rolling codes or challenge‑response, often using AES‑128/256 or similar to prevent cloning and replay.
• Body control module (BCM): Verifies requests and broadcasts commands on the in‑car network (CAN, LIN, or Ethernet) to door modules.
• Door modules and actuators: Small motors and linkages that lock/unlock latches; may include “deadlock/superlock” to disable interior handles.
• Indicators: Hazard lights, horn chirp, mirror fold, and dashboard messages confirming action; some cars also auto‑relock if no door opens.

Together, these components turn a brief, secure radio exchange into a physical action and a visible confirmation, all in a fraction of a second.

What happens when you press the lock button

While implementations vary by brand, the sequence below captures the common steps for a button‑press remote keyless entry (RKE) lock or unlock.

1. The fob wakes and generates a fresh, time‑limited code (rolling code or challenge response), then transmits on its assigned frequency.
2. The car’s receiver demodulates the signal and forwards the message to the BCM.
3. The BCM authenticates it using the shared secret stored in both fob and car; nonces/counters ensure the code hasn’t been replayed.
4. On success, the BCM orders door modules to actuate locks; if configured, it also enables deadlock on a second press.
5. The vehicle flashes indicators or chirps, and may fold mirrors or present handles to confirm; if no door opens after unlock, it may auto‑relock.
6. If several wrong or out‑of‑sync codes arrive, the system refuses requests until resynchronization (typically by pressing the fob near the car).

This process typically takes under half a second, balancing speed with cryptographic checks to keep the exchange secure and resistant to casual interference.

How passive keyless entry and locking work

Hands‑free systems unlock when you pull a handle with the key nearby and lock when you walk away or touch a sensor. They add proximity checks to prevent unauthorized access.

1. The car periodically emits low‑frequency “wake‑up” signals around door handles; touching the handle or approaching strengthens the request.
2. The key responds over UHF/BLE with cryptographic proof of identity; some systems exchange a challenge to ensure freshness.
3. To measure true distance, newer vehicles use UWB distance‑bounding, which is difficult to relay; older systems estimate proximity with LF field strength, which is less secure.
4. If proximity and crypto pass, the BCM authorizes unlock; interior antennas then verify the key is inside before allowing engine start (immobilizer check).
5. For walk‑away locking, the car monitors signal loss and door state; once you step beyond the threshold with all doors closed, it locks and confirms.

Passive entry reduces friction to near zero while adding location awareness, which is why many brands now combine LF for wake‑up with BLE and UWB for secure ranging.

Digital and phone‑as‑key systems

Recent models from BMW, Hyundai/Kia/Genesis, Mercedes‑Benz, Tesla, and others support digital keys that live in your phone or watch. Here’s what underpins them.

• Bluetooth Low Energy: Maintains a low‑power link for presence detection and command exchange; used by Apple Car Key and Android Digital Car Key.
• Ultra‑wideband: Provides centimeter‑level ranging to defeat relay attacks and enable precise door targeting; branded as Digital Key Plus or similar.
• NFC backup: Lets you tap the phone/card at a marked spot to unlock and start when batteries are low.
• Secure elements: Keys are stored in a phone’s secure enclave/TEE; provisioning uses manufacturer apps and vehicle accounts with multi‑factor authentication.
• Standards: Many follow Car Connectivity Consortium Digital Key 3/3.5 profiles, improving cross‑platform compatibility introduced in recent iOS and Android versions.

The result mirrors a physical fob’s experience, but with cloud‑managed sharing and revocation, and—with UWB—stronger protection against relays.

Security: codes, crypto, and common attacks

Automakers use rolling codes and challenge‑response cryptography to stop cloning and replay, yet thieves still target weaknesses like signal relays and jamming. Below are the main risks and mitigations.

• Replay and code‑grabbing: Older systems (e.g., fixed codes, legacy KeeLoq) were vulnerable; modern AES‑based rolling codes and nonces counter this.
• Rolljam: Attackers jam and capture unlock codes to use later; mitigations include counters, short time windows, and dual‑channel checks.
• Relay attacks: Boosters carry your key’s signal to the car to unlock/start; defenses include key motion sensors (sleeping when still), UWB distance‑bounding, PIN‑to‑drive, and Faraday pouches at home.
• RF jamming in parking lots: Prevents locking so a car remains open; visual/audible confirmations and checking the handle help avoid it.
• OBD and in‑car attacks: Once inside, thieves may program new keys via diagnostic ports; OEMs add gateway authentication and immobilizer hardening.
• Software flaws: Vulnerabilities in BLE/UWB stacks can be patched; look for over‑the‑air updates and apply them promptly.

No system is perfect, but layered defenses—modern crypto, UWB ranging, good user habits, and timely updates—significantly reduce risk in day‑to‑day use.

Reliability and range factors

Range and responsiveness depend on radio physics, power, and environment. Expect tens of meters for button‑press fobs, a few meters for passive entry, and tap‑to‑start for NFC.

• Battery health: Weak coin cells shorten fob range; cold weather exacerbates it.
• Interference: Wi‑Fi, other key fobs, and metal structures can attenuate or jam signals.
• Regulatory power limits: Regions cap transmit power differently, affecting range.
• Orientation and shielding: Keys in bags, behind a body, or near metal reduce signal strength.
• Vehicle design: Glass area, antenna placement, and grounding impact performance.
• Protocol choice: UWB/BLE systems manage proximity differently than classic UHF fobs.

If range suddenly drops or operation becomes intermittent, replacing the fob battery and moving away from dense RF environments often restores normal behavior.

What happens inside the doors

After authorization, the body control module signals door modules to drive small electric actuators that move latch linkages. Some cars add features beyond basic lock/unlock.

• Deadlock/superlock: Disables interior handles to thwart forced entry via window breakage; often activated by a second lock press.
• Selective unlocking: First press unlocks the driver door; second press unlocks all.
• Child locks and safe exit: Electronic child locks and radar‑assisted safe‑exit warnings integrate with central locking logic.
• Soft‑close and power doors: Premium models coordinate latches and servos over the vehicle network for smooth operation.

These mechanisms translate the digital authorization into physical security while tailoring behavior to user preferences and safety rules.

Remote start and the immobilizer

Remote locking is separate from the immobilizer, which allows the engine to start only when a valid key is present. Remote start systems must also satisfy the immobilizer—via a secure token exchange—and typically keep the car locked with no shift or drive capability until a valid key is detected inside.

Practical tips

A few habits can improve convenience and security with remote locking, whether you use a fob or a phone key.

• Replace fob batteries proactively (often every 1–2 years) and keep a spare on hand.
• Verify lock confirmations, especially in busy parking areas where jamming is possible.
• Use deadlock mode when parking in public and walk‑away lock when available.
• Store keys away from doors/windows at home; consider a Faraday pouch if relay thefts are common locally.
• Keep vehicle and phone software updated to receive security fixes (BLE/UWB stacks, BCM firmware).
• Know your backup: where the physical blade key is, how to tap with NFC, and how to start if the fob battery dies.

These steps reduce nuisance issues and help the system deliver the convenience and security it was designed for.

Summary

Remote locking works by sending authenticated, time‑limited radio commands from a key fob or phone to a vehicle receiver, which the body control module verifies before driving door actuators and confirming the action. Classic systems use rolling codes over UHF; hands‑free versions add LF wake‑up and, increasingly, BLE and ultra‑wideband for proximity and anti‑relay protection. While attacks like relays and jamming exist, modern crypto, precise ranging, secure elements in phones, and good user practices make today’s remote locking both practical and robust.

How do remote door locks work?

Your smart lock will contain electronic components allowing it to connect to your home internet either via Bluetooth, Wi-Fi, or Z-Wave. This is what gives you remote access to the lock via an internet-enabled smart device. Like all locks, smart locks operate with the use of a lock and a key.

Can you lock yourself out of a car with keyless entry?

Yes, you can lock yourself out of a keyless car, but it depends on the vehicle’s system and settings. While some systems are designed to prevent this by not locking if the fob is detected inside, this feature can fail due to a dead key fob or car battery, or malfunctions in the electronic system. To avoid an accidental lockout, always check for your key fob before closing the car door and familiarize yourself with your car’s emergency access methods. 
How lockouts happen

• System Malfunction: The car’s proximity sensors or electronic locking system may not function correctly, failing to recognize that the key fob is inside. 
• Dead Key Fob or Car Battery: A dead battery in the key fob or the vehicle’s main battery can prevent the system from working and the car from recognizing the key. 
• User Error: You may manually lock the doors with the fob still inside, or the car’s automated lock settings could trigger after a set time. 

How to get back in

• Walk around the car: Check all doors and windows for an unlocked entry point. 
• Use the emergency physical key: Many key fobs contain a small, hidden physical key to unlock the driver’s door. 
• Use a door keypad: Some vehicles with keyless entry also have a door keypad, allowing you to enter a code to unlock the door. 
• Contact a professional: A locksmith can provide professional assistance to help you regain access. 

How to prevent lockouts

• Develop a habit: Always double-check that you have your key fob with you before leaving the car. 
• Know your car’s emergency features: Understand how to use the emergency physical key or door keypad on your specific vehicle model. 

How to lock a car with a remote?

Once you have confirmed that all doors are unlocked tap the X on the upper left of the tile to close the vehicle status. Screen to use the unlock feature. Your car must be locked using icon. App.

What are the disadvantages of keyless entry cars?

Keyless entry cars face disadvantages such as increased risk of theft due to “relay hacking” signal manipulation, higher replacement costs for lost or damaged key fobs, and potential electronic malfunctions caused by dead car or fob batteries, or system faults. They also present a learning curve for users and can lead to accidental engine shutdowns or roll-away risks with push-button start systems. 
Security Vulnerabilities & Theft:

• Relay Hacking: Thieves use signal amplifiers to intercept the communication between the key fob and the car, tricking the vehicle into unlocking and starting, leading to theft. 
• Diagnostic Port Hacking: Criminals can plug devices into the vehicle’s diagnostic port to program blank key fobs and gain entry, according to Compare the Market. 
• Lost/Forgotten Fob: Leaving a key fob inside a car or with a passenger can allow someone else to drive off with the vehicle, even without a legitimate key. 

Operational & Cost Issues:

• Battery Depletion: Both the car’s main battery and the key fob’s battery can die, leaving the owner stranded and unable to access or start the vehicle. 
• High Replacement Costs: Key fobs are expensive to replace, and reprogramming them requires specialized equipment and can be pricier than re-cutting a traditional key. 
• Malfunctions: As with any electronic system, keyless entry components can malfunction, requiring costly electronic repairs. 

User & Safety Concerns:

• Learning Curve: Drivers may need time to get accustomed to keyless start systems, especially understanding how to properly turn off and park the vehicle. 
• Accidental Shutdown: With push-button start systems, there’s a risk of accidentally shutting off the engine at low speeds or failing to turn it off when exiting the vehicle. 
• Increased Risk of Roll-Away Accidents: The quiet operation of modern vehicles with keyless ignition means drivers could forget to turn the engine off, potentially causing it to roll away if not in park.