How Close Does Key Fob Need To Be To Start Car? (2024)

The keyless ignition system is an increasingly popular car feature. This function lets you start your car without searching for a key in your pocket or handbag. But how close should your key fob be to start your vehicle? We researched this question and here is what we learned.

In most circumstances, the key fob needs to be inside the vehicle to start the engine. Moreover, safeguards are built into keyless ignition systems to prevent your vehicle from starting at an unexpected time.

Stay with us as we cover how the keyless ignition system works, what benefits you might enjoy, and what dangers it may impose. In addition, we'll also discuss the different types of keyless ignition systems and what to do in case you have a dead key fob.

How Close Does Key Fob Need To Be To Start Car? (1)

How Does A Keyless Ignition System Work?

The fob that comes with keyless ignition systems can be kept in your pocket, handbag, briefcase, or anywhere close to the receiver within the vehicle.

The fob sends a distinct low-frequency signal to the car's computer network, which verifies that the signal was transmitted correctly and allows you to start the engine by pressing a button on the dashboard or console. It's just as simple to turn off the motor: simply push the start/stop button.

In addition to keyless ignition, most systems provide keyless entry, which allows you to enter the vehicle without having to insert a key or press a button on the fob.

You can watch this video to understand more about keyless ignition:

What Are The Types Of Keyless Ignition Systems?

The keyless ignition system differs from one manufacturer to the next. However, these systems function similarly. The following are some of the common ignition switches:

  • Push-Button Start
  • Smart Key
  • Rotary Switch
  • Rocker Type

Push-Button Start

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The most prevalent keyless ignition type in cars is the push start button. It disarms and starts the car with a key fob. The car will only start if the key fob is within range when you press the engine start button.

After getting into the car, step on the brake and then push and keep holding the start/stop button until your engine starts. To switch off your automobile, make sure it is in parked gear, then press the start/stop button until it completely shuts off. You should also use the parking brake.

Smart Key

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It is the most recent version of the key fob. Within a 5 to 10-footrange, the ignition system can detect key fobs and exclude commands for disarming. The drivers can get inside the vehicle and start it right away.

Smart keys can also be utilized for a variety of additional tasks, such as remotely controlling a climate control system.

Rotary Switch

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These are the traditional ignition systems that require rotation to start and stop the engine.


Turning the engine on and off requires flipping the spring-loaded rocker switches.

What Are The Benefits Of Keyless Ignition Systems?

The most significant advantage of keyless ignitions is increased driving convenience. Moreover, the key fob and ignition's unique security code prevents car theft.

Another advantage of having a keyless system is the variety of driver comfort elements that can be managed remotely. It also reduces car accidents by not starting the engine until the brake pedals are pressed.

A key fob also reduces the possibility of key misplacement or having to scour the depths of your pockets or pocketbook for the keys.

What Are The Dangers Of Keyless Ignition Systems?

On the downside of things, the radio frequencies transmitted by the key fob can be traced and exploited to break into automobile systems. Also, without the fob, the system is inoperable.

As with any electrical component, it wears down with time to the point that you must replace the entire key fob or fix the complete system. Just to be able to start your car again can be an expensive buy.

Another issue is that a technological problem may cause the automobile to fail to recognize the presence of the key fob. In that instance, the vehicle will not start or the engine may lose power.

Here are some safety concerns a keyless ignition system may impose:

  • The combination of keyless ignition and automated stop/start raises the possibility of drivers mistakenly leaving their vehicles running. When this occurs in a garage, you are at risk of carbon monoxide poisoning.
  • Drivers who do not know how to turn off their vehicles' engines in the event of an on-road emergency.
  • Drivers who turn off their vehicles without placing them in "park" and walk away from them, leaving them vulnerable to rolling away — into another car or a person.

How Far Can You Drive Without A Key Fob?

If your car gets stolen or you accidentally dropped your key fob, you may wonder, will your car stop or will it still run?

To answer that, here are some famous vehicle manufacturers and how far their cars can go without a key fob:

  • Audi- 8 to 10 miles
  • Acura- 10 miles/ approximately 20 minutes
  • Jeep- 15 minutes
  • Mercedes- 20 minutes

Although, most car manufacturers allow cars to be driven without limit even if the key fob is not with them. Here are some of those brands:

  • BMW
  • Chevy
  • Honda
  • Dodge
  • Ford
  • Toyota
  • Nissan
  • Hyundai
  • Lexus
  • Mazda
  • Volkswagen
  • Volvo

How Much Does It Cost To Replace A Key Fob?

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If you lost your key fob, replacement fobs can cost somewhere between $250-$600 including the labor for the programming.

But if your fob just ran out of battery, it will only cost you less. Batteries for key fobs typically cost $10 or less, though some fobs require two. Because it simply takes a minute or two, battery specialist shops and dealers frequently replace the batteries for free.

You can read more about the cost of replacing keyless entry fobs in this article: How Much Do Keyless Entry Keys Cost? [What You Need To Know].

What To Do When The Key Fob Runs Out Of Battery?

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In most cars, the technology is designed to work with a remote that has a low battery or is completely dead. Of course, the precise method for using a dead key fob will vary depending on your car's model, so you need to consult your manual for details.

If you have a dead fob, here is what you can do to start your car:

  1. On the rear of your fob, look for a little sliding button. Slide or click the button to release the key fob cover. To get it to release, you may need to use your fingernail and a little force.
  2. Once you've obtained the mechanical key, use it to unlock the door. If you don't see a key slot, it's most likely hidden beneath the handle cover.
  3. To access the key slot, carefully pop off the handle cover with the key.
  4. Close the key fob and replace the mechanical key.
  5. Push the START button with the key fob. Instead of pressing the button with your finger, push the key fob against it. Many manufacturers utilize this as a backup device to ensure that the car can start even if the fob is dead.
  6. Some vehicles include a secret key fob slot that allows you to start the engine. The slot is the ideal size for your fob. Insert the dead key fob into the slot, then use the push-button start as usual.

What Are The Signs That Your Key Fob Needs Battery Replacement?

Even though your key fob appears to be functioning normally, slight anomalies can develop when your battery is nearing the end of its life. You're probably coping with these problems without even recognizing them.

However, these minor inconveniences may gradually lead to more catastrophic repercussions:

  • The signal range of a common fob is between 30 and 60 feet. However, if your remote's battery runs out, it will reduce the range of your fob's operation.
  • You may need to press the button on your fob numerous times before your vehicle recognizes the signal. When this happens, your battery struggles to generate enough power to operate. If this is the case with your key fob, you should replace the battery as soon as possible.
  • Some key fobs are merely used to unlock doors, while others are necessary to start push-to-start engines. It's possible that your key fob is to blame if this component is likewise inconsistent and requires repeated presses.
  • Although you may only have to click the button once, there is a considerable one or two-second delay before hearing your car unlock. This is also a sign that the battery in your key fob is dying.

Final Thoughts

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Now that we live in a time when convenience reigns supreme, it will only be a matter of time before all cars will shift to keyless ignition systems.

For the car to start, the key fob needs to be inside your vehicle. Also, since most keyless cars are powered by push-button ignition, you need to step on the break to power the car.

If you enjoyed this article, be sure to check out these great posts:

What SUVs Have Keyless Entry?

How To Test Keyless Entry Remote.

How Close Does Key Fob Need To Be To Start Car? (2024)


How close does a key fob have to be for a car to start? ›

The vehicle and fob communicate using low-power radio signals that are only effective when the fob is within approximately 36 inches of the car door or ignition start/stop button.

Will a key fob work from anywhere in the car? ›

Keyless ignition systems come with a fob that you can keep tucked away in your pocket, purse, briefcase, or anywhere in close proximity to the receiver inside the vehicle.

Can a low battery key fob cause car not to start? ›

What If My Key Fob Battery Dies? A dead battery in your key fob means it can't broadcast the signal the ignition system is looking for. If your car or truck can't detect the correct signal, then the ignition will remain locked, and you won't be able to start your car with the fob in your pocket.

Can a push start car start with the key outside the car? ›

The fob must be inside the car for the car's computer system to be able to connect with it, allowing the driver to start the car simply by pushing a button.

What is the range of a car fob? ›

Keyless remotes contain a short-range radio transmitter, and must be within a certain range, usually 5–20 meters, of the car to work. When a button is pushed, it sends a coded signal by radio waves to a receiver unit in the car, which locks or unlocks the door.

Can a car start if the key fob is outside the car? ›

There is a limited range and if the driver's door is open, that range will extend somewhat beyond the car's cabin. When the driver's door is closed, the fob must be inside the car for it to start; it's part of the security system.

Can a car drive away without key fob? ›

How far can a keyless car drive without the key? Generally speaking, there's no limit to the distance a vehicle with keyless entry and start can go without the keyfob being in the car. The vehicle will often just beep without the key present.

What happens if you walk away with key fob? ›

The car will stay running (along with music, climate control, etc). The doors won't lock if the fob is in the car, but since you've taken the fob outside the car, you can lock the doors using the fob, or your wife can lock the doors from the inside.

What happens if you drive away from your key fob? ›

If you do, you will need to call a tow, call a friend to pick up your fob or start walking home to get the fob. What happens if I drive off without my key fob? The car will say the key has left the vehicle and will keep running until you turn it off.

How long does a key fob battery last? ›

- For a regular key fob the life expectancy of the battery lasts 4-6 Years. - The life expectancy of a Smart key fob battery is around 2-3 Years.

What causes key fob to not start car? ›

An antenna or wiring fault in the keyless entry system, software issues, a damaged circuit board, or a faulty start button are all possible culprits. Consider having the vehicle inspected for any repair needs.

How far can a keyless car drive without the key? ›

You can drive a short distance without using a key fob in some cars (some key jobs can operate more than 30 to 50 feet) and If you expect to drive farther than that, you have to need your key. Normally, drivers can continue driving until they turn off the ignition system.

Can you steal a push start car without the key fob? ›

Whether thieves use the relay technique, use a jamming device or simply break a window, once they're inside the car, those vehicles with a start button rather than an ignition key can be simple to steal. Every car sold for more than a decade has been required to have a standard diagnostic port fitted.

What can block key fob signal? ›

Store the fob as far away as possible from the car and away from glass doors and windows. Or, buy an inexpensive RF-blocking box or pouch. It's lined with metal and will interrupt the signal.

What can interfere with key fob signal? ›

"Radio interference is a possible cause if the key fobs stop operating all of a sudden. Wireless devices such as radar detectors and anti-theft alarms can interfere with the key fob signals by transmitting at the same frequency."

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