How to protect your car for free

You don’t need any expensive or awkward-to-use products to stop theives stealing your car!

Car manufacturers have already provided a “secret switch” for owners to easily prevent signal relay attacks.

See instructions below for which buttons to press on your key fob, in order to disable keyless entry overnight or whenever you choose.

Audi

[Temporary]

Press “lock” button once (to be confirmed)
- See manual, page 40

Bentley

Unknown

BMW

[Temporary]

Press the “lock” button on the digital key/remote control key fob
From the manual:
- ▷ If the vehicle was locked with the remote control, it cannot be unlocked touchless.
- ▷ If the vehicle has been in the idle state for several days, touchless unlocking and locking is not possible until after the vehicle has been driven.

Ferrari

Unknown

Ford

[Temporary] Lock the car by pressing the button on the remote control key (to be confirmed)
[Automatic] “Sleeping key fob” feature deactivates transmitter if key fob has not moved for 40 seconds (Fiesta/Focus, 2019 onwards)
[Permanent] Disable “Passive entry” in the car’s menu (Fiesta 2016, Focus 2017 onwards)

Hyundai

Unknown

Jaguar

[Permanent] (2013 F-Type, Discovery Sport)

Open driver’s door (using fob)
Key fob inside car
Press headlamp button on the key fob 3 times
Press unlock button on the key fob once
Keys outside car
Close driver’s door
Lock car using the fob
Unlock car using the fob

Notes:

Same procedure again to re-enable it, except press the lock button at step 4.
You have to make sure you first unlock and then re-lock the car with the fob, not the keyless button on the door.

(source, source, source)

Kia

Unknown

Lexus

[Temporary]

Press lock button and keep it pressed
At the same time, press unlock button twice
After 1 second, the light on the key fob will flash an extra time

Mazda

[Permanent] (2021+)

By turning on the transmitter power saving function, the advanced keyless entry and push button start system functions turn off and the battery power consumption of the transmitter is restricted.

Turning on the power saving function:

Press the lock button on the transmitter 4 times within 3 seconds to turn on the operation indicator light.
Press the lock button continuously for 1.5 seconds or longer while the operation indicator light turns on (for 5 seconds).
Press any of the buttons on the transmitter to make sure that the operation indicator light does not turn on/flash.

Turning off the power saving function:

Press the lock button on the transmitter 4 times within 3 seconds to turn on the operation indicator light.
Press the lock button continuously for 1.5 seconds or longer while the operation indicator light turns on (for 5 seconds).

NOTE: Once you turn this on, the car will not start with the key until you either turn the power save mode off, or place the key against the start/stop button while pressing it.

Source: Owner’s Manual

Mercedes

[Temporary]

Lock car as usual
Press lock button again twice quickly

Mini

Unknown

MG

Unknown

Nissan

[Permanent] (Qashqai)

Settings -> vehicle -> locking
Change the i-key setting to “off”

[Automatic]

Latest key fobs turn off after a period of inactivity (J12 onwards?)

Feature is called “i-key” (intelligent key).

Peugeot

Unknown

Porsche

[Temporary]

Press lock button and keep it pressed.
At the same time, press the unlock button within 1 second
Keep both buttons pressed until the indicator light on the vehicle key lights up continuously

Range Rover

[Temporary]

With the key inside car and door open,
Press headlight button 3 times, then unlock button
Then just lock car with fob as normal

Škoda

Unknown

Subaru

Unknown

Tesla

[Temporary]

Press the “lock” button once (to be confirmed)

[Permanent]

To disable keyless entry completely (Model S):
- Go to the Settings tab on the center touchscreen
- Then to the Doors & Locks menu
- Switch ‘Passive Entry’ OFF (must press brake pedal)

Toyota

[Temporary]

Press lock button and keep it pressed
At the same time, press unlock button twice (Tacoma)

Vauxhall

Unknown

Volkswagen

[Temporary]

Lock the car with the key fob
then press the little indented area on the door handle
keyless entry is now disabled until you unlock the car again (T-roc 7 onwards?)

[Automatic]

Key fob goes to sleep after 15 minutes inactivity (T-Cross)

Note: VW keyless entry feature is called “KESSY”

Other cars

Submissions welcome

Explanation

Most of us leave our car keys in the hallway of our house which is a short distance away from our car. Thieves use special equipment to boost the signal from your car’s keyless entry fob so the signal can reach all the way to your car and unlock it. They can even do this if you keep your keys in a room on the opposite side of your house.

A common solution is to keep your keys in a specially designed “Faraday box” or pouch which blocks the signal, but this doesn’t work well for many. You could forget to put the keys there, or not want to spend the time and money. Pouches can also fail to work after some time. People have tried using tin foil instead, but it’s still a bit of a faff.

There are other more elaborate devices to solve the problem, but they often carry a significant cost.

This page explains the official methods that your car manufacturer designed to prevent thieves carrying out signal boosting to steal your car.

Types of disabling

This page describes, for each car type, up to three different ways to disable the keyless entry feature:

Temporarily disable. This is most useful if you want to use the keyless entry when convenient to you, but turn it off overnight or when you go on holiday. You have to remember to do it each evening. Keyless entry will stay deactivated until you next unlock the car by physically pressing the button on the key fob.
Automatically disable. This is the best option, because you don’t need to do anything different to keep your car safe. They key fob turns itself off after you put it down. When you pick it up and put in your pocket, it reactivates. Unfortunately not all car manufacturers have provided this feature.
Permanently disable. Follow these instructions if you never want to use keyless entry. It protects the vehicle from this specific type of keyless entry theft.

Other methods of preventing car theft

Put your keys in a little bag that blocks the signals called a “Faraday pouch”. Not recommended, because in my experience these degrade over time and let signals through.
Keep the keys on the other side of the house, far away from the car. Not recommended, because the signal can still be relayed with the right equipment.
Put your keys in the microwave (Not tested. Has anyone tried this?)
Permanently disable keyless entry (AKA passive entry). Often possible from the car’s on-board touch-screen computer. Check the manual or ask your car dealer.
Electronic immobiliser. All cars since 1998 already have a factory-fitted electronic immobiliser(*), but these are ineffective against relay attacks because the car’s system has been tricked into thinking the correct key is present.
Ghost immobiliser. May protect against keyless car theft by providing an extra layer of security. Significant cost of installation.
Thatcham mechanical wheel lock. A good idea if you can tolerate the inconvenience. Will definitely make your car more difficult to steal, whether by relay attack or any other method.
Disable or lock the data port. Modern cars have electronic systems which are accessed via an “On-Board Diagnostics” (OBD) port. After gaining physical access to the vehicle, it is possible for thieves to plug equipment into the ODB port and hack the information neeed to start the car.
Fit a tracker. Does not actually prevent the car being stolen, it’s more of a deterrent (if the thieves are aware of it). Not ideal as you might have to travel quite a distance to reach the car’s new location. It could be still be inaccessible or dangerous to approach. And a shipping container or even a car park might block the tracker signal.

Reassurances

Even when “keyless” or “passive” entry is disabled, it’s still common to press a button on they key fob to unlock the door. You probably don’t need to worry about the risk of thieves capturing that signal and replaying it later to steal your car. Firstly the signal is different for locking and unlocking the car. When you lock the car and leave, copying that signal would only help someone lock the car again! And when you unlock the car it’s because you’re about to get into it and drive off, so any potential thieves would need to follow your car. That is a lot of effort to go to, and presumably car theft most commonly occurs in low-effort, low-risk scenarios.
A number of manufacturers have introduced preventative measures aimed at curbing keyless car theft. Fobs provided by car companies such as BMW, Audi, Ford and Mercedes now come fitted with a motion sensor that automatically deactivates the signal when the key is not moving; this prevents the signal being relayed when the key is left overnight, for example. Jaguar and Land Rover, meanwhile, use ultra wide-band radio technology, which stops thieves being able to isolate the signal to your car. (read more)

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