Car Starts Without Key [Causes & Fixes]

Have you ever approached your car anticipating to search for your keys only to discover that it had already started? 

To be honest, it’s an extremely weird and unsettling experience. 

For years, this strange occurrence of a vehicle starting without keys has perplexed many car owners and experts. It is an unusual thing and can be quite alarming. If this is your current situation, we encourage you to read this post till the end.

In this post, we’ll look at a few potential causes why your car might start without a key and how to address the situation.

Car Starts Without Key

What Causes a Car to Start Without a Key?

1. Keyless Entry System Malfunction

A keyless entry system malfunction is one of the most frequent causes of a vehicle starting without a set of keys. Keyless entry systems are common in many modern vehicles, enabling the driver to open and start the vehicle without the need for a physical key. 

To interact with the car’s computer, these systems use radio frequency identification (RFID) technology. The car’s computer may not detect the key fob if the keyless entry system isn’t working properly, which could result in the car starting without keys. 

This may occur if the key fob’s battery is dead or if there is a problem with its setting.

2. Faulty Ignition Switch

A broken ignition switch is another factor that makes a car start without keys. The ignition switch is in charge of communicating with the vehicle’s computer to turn on the motor.

The broken ignition switch can send a false signal to the computer, allowing the vehicle to start without the keys.

3. Wiring Issues

A vehicle can also start without keys because of wiring problems. A short circuit in the wiring can send the computer a false signal, triggering it to start the engine without the key.

Incorrect wiring can also result in other issues with the car’s electrical system, such as a dead battery or broken lights.

4. Hacking

Occasionally, by hacking, a vehicle can start without the keys. Hackers can access a car’s computer system using sophisticated tools and start the motor without a key.

Because of the serious security risks caused by this, manufacturers are continuously striving to improve the safety of their vehicles.

How to Fix a Car Starting Without a Key

Sometimes when your vehicle starts without a key, there may be an underlying issue that needs to be fixed. Here are some actions you can take to resolve the situation:

1. Check the Key Fob Battery

Check the battery in the key fob if your vehicle has a keyless entry system. The vehicle may start without a key if the battery is dead or low. Replace the battery and restart the vehicle.

2. Inspect the Ignition Switch

Examine the ignition switch for indications of wear or damage. If the switch is defective, it may have to be changed. A qualified mechanic can identify and repair the problem.

3. Examine the Wiring

Inspect the car’s wiring for signs of damage or corrosion. A short circuit or a loose connection can cause the vehicle to start without a key. A mechanic can fix or replace any damaged wiring.

4. Reset your Car’s Computer

If none of the above solutions works, you can attempt resetting the car’s computer. Disconnect and reconnect the battery wires after a few minutes. This will restart the machine and may fix the problem.

5. Contact a Professional

If you are not sure about diagnosing and repairing the problem yourself, it is best to consult a qualified mechanic. They know to correctly and efficiently diagnose and repair the problem.

What is a Keyless Ignition System in Cars?

A keyless ignition system is a type of technology that enables drivers to start and stop their vehicles without the use of a conventional metal key. To start the vehicle, a fob or a card with a unique code is used instead.

The keyless ignition device employs radio-frequency identification (RFID) and push-button ignition. When the driver approaches the car with the fob or card, the car’s sensors detect the code and instantly open the doors. Once inside, the driver can depress the stop pedal and activate the engine by pressing a button.

The keyless ignition device provides several advantages to drivers. For example, it removes the need to carry a bulky keychain, which is particularly useful for those who travel or commute frequently. 

The keyless ignition system can reduce the risk of theft by preventing the engine from starting without the appropriate fob or card. 

Read: Nissan Altima Bluetooth Not Working [Causes & Fixes]


If your car starts without a key, it’s important not to panic. Although it can be a strange and unsettling occurrence when a vehicle starts without the keys, it is not always a reason for alarm. 

This could occur for several reasons, such as a broken ignition switch, a keyless entry system that isn’t working properly, wiring problems, or hacking.

Follow the steps outlined above to determine the cause of the issue and take the right action. But if you can not determine the problem, you can take your car to a qualified mechanic to identify and resolve the issue.