Keyless cars (officially “Passive Keyless Entry and Start” systems) offer fantastic convenience, but they come with unique risks and nuances that every owner should understand.
Here are 10 vital things to know about keyless cars:
1. The “Relay Attack” is the Biggest Security Threat
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What it is: Thieves use two electronic devices that amplify the signal from your key fob (e.g., from inside your house) to your car, tricking it into thinking the key is present. This allows them to unlock and start the car in seconds.
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How to Defend:
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Store your keys in a Faraday Bag/Pouch (signal-blocking pouch). Test it to ensure it works.
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Don’t leave keys near the front door or windows. Put them in a central location in your home.
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2. A Car That’s “Off” May Not Be Fully Off
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The Risk: If you don’t press the start/stop button firmly or correctly, the car may only go into “Accessory” mode instead of turning off completely. This can drain the 12V battery overnight.
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The Habit: Always check that the dashboard is completely blank and the ignition is off before exiting the vehicle. Listen for the engine to shut off.
3. “Dead Key Fob” Procedures Exist – Learn Them
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The Problem: The key fob’s battery will die eventually, leaving you unable to start the car normally.
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The Solution: Your owner’s manual has the solution. Most keyless cars have a specific spot (often in the cup holder or against the steering column) where you can place the dead fob. This allows the car to detect it via direct induction, letting you start the car. Know where this spot is before you need it.
4. The “Rolling Code” is Not Foolproof
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What it is: To prevent simple code-copying, your key and car sync to a new code every time you use it.
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The Limitation: While this stops basic code grabbers, it doesn’t protect against the more sophisticated Relay Attack mentioned in point #1.
5. You Can Accidentally Lock Your Key Fob in the Trunk
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The Scenario: You place your keys in the trunk while unloading groceries, shut the trunk, and it locks automatically—with the keys inside.
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The Safeguard: Most modern keyless cars have a sensor in the trunk that will prevent it from locking if it detects the key fob inside. However, this system can fail. Never leave your keys in the trunk intentionally.
6. The Risk of “Walk-Away Locking” is Real
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The Convenience: Many cars automatically lock when you walk away with the key fob.
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The Danger: If you walk away from the car while a passenger (especially a child or pet) is still inside, the car may lock with them inside. Always visually confirm everyone is out before walking away.
7. Keyless Cars are Silent and Present a Carbon Monoxide Risk
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The Scenario: Because the engine starts with a button and is often very quiet, it’s easy to exit the car while it’s still running, especially hybrids in electric mode.
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The Danger: If you do this in an enclosed space like a garage, deadly carbon monoxide can fill your home. Always double-check your car is off. Some cars now have warning beeps to alert you if you walk away while the engine is running.
8. Your 12V Battery is Still Critical
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The Misconception: People often think the keyless system runs off the main hybrid or EV battery.
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The Reality: The keyless entry, start system, and all computers run on the traditional 12V battery. If it dies, you will be locked out and unable to start the car, just like a conventional vehicle. A flat 12V battery is a common cause of keyless system failure.
9. Key Fob Batteries Drain Faster Than You Think
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The Cause: The key fob is constantly “listening” for a signal from the car, which drains its small battery.
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The Tip: The average key fob battery lasts 2-4 years. Replace it proactively to avoid being stranded. Keep a spare battery in your wallet or glove box.
10. You are Responsible for Key Fob Security
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The Rule: Insurance companies and police consider it the owner’s responsibility to secure the key signal. If your car is stolen via a relay attack and your keys were left by the front door, your insurance claim could potentially be questioned.
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The Bottom Line: Using a Faraday bag or a metal tin is not just a tip; it’s a crucial part of your car’s security system, just like locking the doors.