Anti-theft systems are designed to prevent your vehicle from being stolen. These systems are constantly evolving. Essentially, how they work is by an electrical circuit disconnecting to prevent power from flowing in some fashion so your car won’t start or to die immediately. An anti-theft system may also integrate a car alarm or it might be just an engine immobilizer.

It’s possible that the anti-theft system in your car won’t function correctly at some point. This may be for many reasons including a dead car battery that loses its key memory or a dead battery in your remote. It could also be that your immobilizer chip is damaged in your key or the car door lock is damaged.

If your car’s anti-theft system isn’t working correctly, you’ll need to find a way to shut the system off so your car will return to normal operation.

Method 1 of 3: Check your key and cylinder

Step 1: Check your key fob battery. A car’s anti-theft system may activate if your key fob battery is dead and hasn’t disabled the system.

Make sure the battery is installed correctly in your key fob. If the battery is correctly installed, replace it with a fresh battery and try again.

Step 2: Check your door lock cylinder. If your car has been damaged in an attempt to steal it or break into it, the anti-theft system may have been engaged.

Check for damage to the lock cylinder itself or under the door handle where would-be thieves may have punched through with a screwdriver. If the lock is damaged, try using the passenger side cylinder if your car has one.

  • Note: While the driver’s side door lock is damaged, typically the passenger side won’t also be.

Step 3: Check that you are using the proper key to start your car. Many cars have a “valet” key or a door key that only performs certain functions such as unlocking the doors.

“Valet” keys are often distinguished by a “V” on the key shaft or a different-colored key head. The key you are using may not have the chip required to start your car.

Method 2 of 3: Turn the ignition on

If the anti-theft system has locked up your engine, you won’t be able to start it. You’ll have to disable it with these steps.

Step 1: Check for the anti-theft light. It’s located on your dash and will have a blue or red light.

Step 2: Turn the ignition to the "on" position. Insert the key into the ignition and turn it to the on position, which activates your accessories but not the engine.

Leave the key in position for about 10 – 15 minutes.

Step 3: Check the anti-theft light again. If it’s no longer blinking, turn the key back to the Off position and allow it to set for a minute or two.

This gives the system time to reset or you won’t be able to start your car.

Step 4: Start the engine. Attempt to start your engine.

If it still won’t start, check to make sure the battery hasn’t been drained.

Step 5: Repeat the process. Try the process over again to see if it will work.

Method 3 of 3: Use the key in your car door

Step 1: Insert your key in the lock on the door. Use the driver’s side door and the physical key even if your vehicle is equipped with a keyless entry system.

Step 2: Turn the key. Turn the key to unlock your car door, but don’t release it.

Hold the key in this position for 20 to 30 seconds. This lets the system know you have the correct key, and it can allow you to bypass the alarm system. Some vehicles recognize the key simply by turning the key back and forth in the door lock key cylinder.

  • Tip: Try turning the key both ways fully to disable the anti-theft system.

Step 3: Try to start the engine. Remove the key and try to start the engine.

Be sure to leave the key cylinder in the unlocked position.

An anti-theft system that prevents your car from running properly is a nuisance, and while you may be thankful for it in the event of a crime, it is now causing you a great deal of inconvenience, which these steps have hopefully helped you resolve. If your car still won't start, you should consult with a professional from YourMechanic to determine if there is another issue that is preventing your car from starting.

This article originally appeared on YourMechanic.com as How to Shut Off the Anti-Theft Device in Your Car and was authored by Jason Unrau.


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