Will Dead Battery in Key Fob Cause Car Not to Start

  • A dead battery in a key fob can cause a car not to start.
  • The key fob is responsible for transmitting signals to the car’s immobilizer system, which allows the engine to start.
  • When the battery in the key fob dies, it can no longer transmit signals to the immobilizer system, causing the engine not to start.
  • If you suspect that your key fob battery is dead, try replacing it with a new one and see if that solves the problem.
  • If replacing the battery doesn’t work, there may be an issue with either the key fob or the car’s immobilizer system. In this case, it’s best to consult a professional mechanic for further diagnosis and repair.

Picture this scenario: you’re on your way to work, running late as usual, and you jump in your car ready to head out. You press the brake and hit the start button, but nothing happens. Your heart drops as you try again with no luck. Suddenly, you remember that the battery in your key fob has been acting up lately. Could that be the reason why your car won’t start?

It’s a frustrating situation that many of us have experienced before. We rely so heavily on our cars to get us where we need to go, and any issue can throw off our entire day. But when it comes to a dead battery in your key fob causing your car not to start, is that really possible? In this article, we’ll dive into the details of how key fobs work and whether or not a dead battery can prevent your car from starting. So sit back, relax (if you can), and let’s unravel this mystery together.

The Quick Answer:

A key fob is a small electronic device that wirelessly controls various functions of a car, such as locking and unlocking doors, popping open the trunk, and starting the engine. It uses radio frequency identification (RFID) technology to communicate with the car’s computer system. A dead battery in the key fob may cause buttons to stop working or reduce signal range, but it should not prevent the car from starting.

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What is a key fob and how does it work?

A key fob, also known as a remote or clicker, is a small electronic device that controls various functions of a car. Key fobs come in different shapes and sizes but they usually have buttons for locking and unlocking the doors, popping open the trunk, starting the engine, and setting off an alarm.

The technology behind key fobs is based on radio frequency identification (RFID) which allows the device to communicate wirelessly with the car’s computer system. When you press a button on the key fob, it sends a signal to the car’s receiver which then performs the desired action.

Key fobs are powered by batteries which can last anywhere from several months to several years depending on usage. Some newer models of cars have keyless entry systems which use proximity sensors instead of buttons to detect when someone is nearby with the key fob.

Can a dead battery in a key fob cause the car not to start?

No, a dead battery in a key fob should not prevent your car from starting. The purpose of a key fob is to send signals wirelessly to your car’s computer system which then performs certain functions such as unlocking doors or starting the engine.

If your car doesn’t start after turning the ignition switch, it could be due to other factors such as a faulty starter motor, alternator or fuel pump. In some cases, there may be an issue with the security system that prevents your car from starting if it doesn’t detect an authorized key signal.

What are the symptoms of a dead battery in a key fob?

1. Buttons don’t work

The most obvious symptom of a dead battery in your key fob is that the buttons on the device stop working. You may notice that pressing the lock or unlock button doesn’t do anything, or that the range of the signal is greatly reduced.

2. Warning light on dashboard

If your car has a warning light for key fob battery low, it means that your car’s computer system has detected a weak signal from your key fob and is alerting you to replace the battery soon.

3. Car won’t start

In rare cases, a dead battery in your key fob can cause issues with starting your car if there is an immobilizer system installed in your vehicle. The immobilizer system prevents unauthorized access to your car by only allowing it to start when a specific code from the key fob matches with its database.

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How can I replace the battery in my key fob?

The process of replacing a battery in a key fob varies depending on the make and model of your device. However, most key fobs have similar steps:

1. Open up the key fob

  • Locate the seam between two halves of the key fob case and use a flathead screwdriver or coin to pry them apart.
  • Be careful not to damage any internal components while opening up the device.

2. Remove old battery

  • Locate where the battery sits in your key fob.
  • Carefully remove the old battery using tweezers or a small flathead screwdriver.

3. Install new battery

  • Note down which side of the battery is facing up before removing it from the packaging.
  • Insert the new battery in the same orientation as the old one.

4. Reassemble key fob

  • Carefully snap the two halves of the key fob back together until you hear a click or feel them lock into place.
  • Test your key fob to make sure that all buttons work correctly and that the range is adequate.

Are there any other reasons why my car may not start even if the key fob battery is fine?

Yes, there can be several other reasons why your car won’t start even if your key fob battery is fine:

1. Dead starter motor or solenoid

If you turn the ignition key and your engine doesn’t crank over, it could be due to a dead starter motor or solenoid. The starter motor engages with your engine’s flywheel to turn it over, while the solenoid activates electrical current to reach the starter motor and engage it.

2. Bad alternator

The alternator charges your car’s battery while you’re driving, but if it goes bad, then it won’t supply enough charge to keep your battery running for long enough periods.

3. Fuel pump failure

The fuel pump is responsible for delivering gasoline from your tank to your engine. If it fails, then you’ll have no fuel going into your engine which means you won’t be able to start your car.

What should I do if my car still won’t start after replacing the key fob battery?

If replacing the key fob battery doesn’t fix the issue of your car not starting, then you should try the following:

1. Check for other symptoms

Look for any other symptoms such as warning lights on your dashboard or strange noises coming from your engine. This can help narrow down the cause of the problem.

2. Try a different key fob

If you have another key fob that works with your car, try using it to see if it starts. If it does, then the issue may be with the original key fob.

3. Call a mechanic

If none of these steps work, then it’s time to call a mechanic who can use diagnostic tools to pinpoint the exact cause of why your car isn’t starting.

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How can I prevent my key fob battery from dying prematurely?

To prolong the life of your key fob battery, you can follow these tips:

1. Use sparingly

Avoid using your key fob excessively when not necessary as each button press consumes some power which can drain the battery over time.

2. Keep away from heat

Avoid exposing your key fob to excessive heat since it can damage both the device and its battery.

3. Replace battery in time

If you notice any signs of a weak battery such as reduced range or non-functioning buttons, replace them immediately before they die completely.

4. Store properly

When storing your key fob for extended periods like when going on vacation, remove its batteries and store them separately in a cool and dry place where they won’t get damaged by moisture or humidity.

In conclusion, a dead battery in the key fob can prevent a car from starting and it is important to check and replace the battery regularly to avoid any inconvenience.

Frequently Asked Questions about Will Dead Battery in Key Fob Cause Car Not to Start

Why is my key fob not letting me start my car?
If your remote starter is malfunctioning, consider changing the battery in your key fob. Replacement key fob batteries can be found at Batteries Plus and most remote starters use 2032 lithium coin cell batteries. It is important to note that if your car is not in “Park”, the remote starter will not function properly.

Can dead battery cause key not to turn in the ignition?
In many high-end cars with advanced electronic ignition systems, if the battery is dead, the key may not turn. To confirm this issue, it is recommended to check the battery’s lifespan.

Why won t my car start after changing battery in key fob?
In the event that your key fob does not work after replacing its batteries, you may need to either reprogram it or inspect it for faulty buttons and damaged battery connectors. If you have already replaced the battery in your remote key fob and it still does not function properly, reprogramming the key may be necessary. This information was provided on April 27, 2023.

Why won’t my car start when I turn the ignition?
If you turn the key and only hear a single click without the engine starting, it may be due to an issue with the electrical system, specifically the starter motor. The starter motor is responsible for physically starting the engine, and if it’s not functioning properly, a replacement is necessary.

Can a dead key fob drain your battery?
According to Consumer Reports’ road test manager, Mike Monticello, a key fob for a car will consistently attempt to communicate with the vehicle, which can use some battery power. However, this is usually not enough to completely drain a healthy car battery. Essentially, the key fob contributes to the battery issue.

Do I need to reprogram my car after battery replacement?
The latest battery doesn’t need to be programmed for the latest car models. No registration is needed, but it’s advisable to check the electrical functions after installing the new battery.

Technical writer with 3+ years of experience. Bachelor of Arts in Environmental Studies from UC Santa Cruz. Passionate about sustainability and providing clear, concise how-to guides for common battery problems.

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