How To Disengage Anti Theft System? The Underlying Process

Steps to Disable Car Anti-Theft System

1. Use Key Fob

The most obvious way to get around the anti-theft system is to use the key fob. By pressing the alarm button, you should get it turned off. When everything is working as it should, this is the easiest way to turn the system off and get back on the road. 

If you are having trouble with the key fob, it could be where you are located. Sometimes, it won’t work if you aren’t close enough to your car. Additionally, if there are other vehicles between you and your car, there could be interference. Try it again when you get closer.

However, the battery in the key fob can also fail. If the key fob battery is dead or there’s another malfunction, you might need to try one of the other steps instead.

RELATED: Car Alarm Keeps Going Off Randomly?

2. Try Key in Door

As the key fob starts to die, it might no longer disable the alarm. Still, you should be able to use the key until you get home to change the fob’s battery.

When you put the key into your driver’s side door lock, turn it and hold it in place for about twenty seconds. This time allows the vehicle to recognize the key, ensuring the system shuts off. You might also try turning the key a few times in the lock to get the system to recognize it. 

3. Examine Key/Cylinder

If the key in the door lock isn’t working, it’s possible you are using the wrong key. Take a closer look at it to ensure it’s the right match. Maybe you grabbed your spouse’s keys when you walked out the door this morning. 

Additionally, any damage done to the door lock cylinder can cause the alarm to go off. If there’s damage, the system could inadvertently believe someone is trying to break in. This is a common area thieves attack when trying to break into a car. The only solution at this point would be to replace the door lock cylinder.

RELATED: Key Fob Dead? Here’s How to Unlock & Start it

4. Turn on Ignition

If you have gotten into the car, it’s possible to reset the system. With a little patience, you might be able to deactivate the alarm by trying to start the car.

Obviously, the car isn’t going to start while the alarm is activated, but the same steps might help deactivate it. If the anti-theft device light is on the dash, put your key in the ignition and turn it ON. At this position, the accessories are activated, such as the radio. 

If the system resets itself, the light will go off. In some cases, this could take several minutes of waiting. Once the light is off, you should be able to start the vehicle as normal. There’s also the chance that the light went off because you drained the battery, which means you have another problem to think about. 

5. Remove Alarm Fuse

A quick fix to get the alarm to stop sounding is to remove the fuse. This will also provide a soft reboot to the immobilizer.

You can find the alarm fuse in the panel. Look in the owner’s manual to find the exact location of the fuse used by the security system. While the fuse is out, the car is not going to start. However, you can reinsert it and hopefully reset the alarm. 

RELATED: How to Program a Key Fob Yourself at Home

6. Disconnect Battery

If nothing else has worked, it’s time to disconnect the car battery. If your alarm is blaring and you just want to turn it off, get under the hood and stop it by disconnecting the battery cables. 

Once the battery is unplugged for a few minutes, the computer is going to reset. Wait a few minutes before you reconnect it. If the system hasn’t reset and you still can’t get around the anti-theft system, it’s time to call for professional help. 


Check key and cylinder

Sometimes your alarm will start to go off if the battery in your key fob is getting low. This is to warn you that it is getting low so you don’t have to deal with being locked out of your car or having to use the key to get in the car. If the alarm starts going off randomly, then the first thing you should do is switch the battery in your remote. You will then have to wait a few days and see if that fixes the problem. If it does, then you are good to go, but if it doesn’t, then you will have to investigate farther.

The next thing you should check is making sure that the door lock cylinder isn’t damaged. The door lock cylinder is on the inside of the door where it latches to the body of the car. If it looks damaged or seems like that it isn’t making a good latch, then that might be the cause of the alarm going off. This is because the car might think someone is trying to pry the door open. Also, you should check under the door handle where someone would try to punch a screwdriver thru to open the locked door. If this area is damaged, then it could be triggering the alarm. If the door lock cylinder looks damaged, then try replacing it and seeing if that fixes the issue.

The last thing you need to check is back to the key, and that is making sure you are using the right one. Some cars have valet keys that are only designed to do certain things, and if you are using the wrong key, then it can set the car off. This is because the car will think you are trying to use a fake key. Also, some cars have chips in one key but not another, so make sure you are using the one with the chip. When you get in a hurry, it is easier than you might think to try to use the wrong key and that will trigger our anti-theft system.

Next Step

Schedule Electric Problems Inspection

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Nissan Infiniti Security Reset

Call into the dealer, this is their response: Using the fob hit unlock button. Use the ignition key to start the car. Use the key to unlock the driver’s door. Remove the negative battery cable and then reconnect.

Audi Immobilizer Reset Instructions

Call to the dealer, this was their response: With the ignition key try to start the vehicle. Exit the vehicle and lock all door with the windows up, then unlock the doors using the key fob the engine should start. Disconnect the battery using the negative cable wait one minute and reconnect.

How To Deactivate Toyota Immobilizer Using Car Door Key

The engine immobilizer works due to the matching code found in a chip in your car key and the ECU. If you want to switch off the immobilizer, you will need to use the car door key. 

An engine immobilizer would be a pointless feature if anyone could deactivate it, agreed? That is why the key plays such an important role in deactivating the immobilizer.

Follow this step-by-step guide to successfully deactivate the engine immobilizer in your Toyota: 

Step 1 – Put the key into the lock on the car door.

Step 2 – Turn the key as if you were going to unlock the car but don’t open the door. 

Step 3 – Hold the car key in place in the lock for approximately 30 seconds. Leaving the key in the lock for this time will signal to the immobilizer that you are using the legitimate key to unlock the car.

Step 4 – Turn the key both ways – lock and unlock – and this action will bypass and deactivate the engine immobilizer. You need to give the Toyota immobilizer time to recognize the key so the immobilizer can be successfully deactivated. 

Step 5 – Keep the door in the unlock position and start the engine. The immobilizer should now be reset. 

Use Key in Door

Another tip you can use to try to disable your anti-theft system is to use the key in the door. You want to make sure to use the driver side door and the physical key to having a chance of this working. Insert the key in the door lock all the way and then turn the key to unlock your car door, but don’t release it. You want to hold the key in the unlock position for twenty to thirty seconds. This lets the car recognize that you have the right key and will disengage and reset the system. If this doesn’t work, then you can try to turn the key back and forth in the lock a few times. Some cars will recognize the key this way if the key is being turned in the door lock cylinder. If using this method shuts the alarm off and disengages the anti-theft system, then you can try to start the car.

Third: Keep a fob battery in the car

Any large grocery store or pharmacy will sell the batteries that go in key fobs. Stick one in the glove compartment, replace it or check that it’s still good every two or three years. The first time you press the button and don’t get that reassuring “click!” from the door locks, you can grab the spare battery and to quickly rule out an easy issue.

If you’ve taken the preventive measures and the car still won’t start, here are a few strategies for getting around the anti-theft devices.

Method 1: Unlock the door with the mechanical key, Part 1

If the vehicle won’t respond to fob commands, remove the mechanical key from the fob and use it to open the doors. That can let the vehicle know the key you have is security cleared. Depending on the vehicle, you might be able to start the engine with the mechanical key; on some push-to-start cars, the pushbutton cover can be removed to reveal a traditional ignition cylinder lock. On other vehicles, you’ll need to locate the backup fob holder slot. The slot will contain a transponder that can recognize the key. 

Method 2: Unlock the door with the mechanical key, Part 2

This is a more involved way to get the car to recognize the key. First try placing the mechanical key in the door lock, then unlock the door, lock the door, and unlock the door again. Try starting the car. 

If that doesn’t work, place the mechanical key in the door lock, but when you turn the key to unlock the door, hold the key at the end of the turn for 30 seconds before returning the key to the neutral position. Try to start the car. If this doesn’t work, get out and lock the car with the key, then repeat the unlock-and-hold method, then try to start the car.

Some vehicles need a “cheat code” to get this method to work. Certain Honda Accord models, for instance, require turning the key to unlock, lock, lock again, then unlock before starting, and letting the car run for 10 minutes to reset the anti-theft system.

Method 3: Turn the ignition to “On”

If your car has a mechanical key ignition cylinder and still won’t start, a flashing or constantly illuminated anti-theft system light might alert you to the fault here. You can try giving the car time to re-recognize the key. Put the key in the ignition and rotate forward two clicks to the “On” position that makes the dashboard light up, but don’t try starting the car. Leave the key there for 15 minutes; it doesn’t always take that long, but it can.

After that time, check to see if the anti-theft light has gone out, if one was lit up. Turn the key backward two places to the Lock position, then wait three more minutes. When that has elapsed, try to start the car.

Method 4: Check the fuses

There’s often a fuse associated with the immobilizer, and like all fuses, it can blow. Check the owner’s manual to locate the fuse and assess its condition. Another handy preventive tip is to always carry a few fuses in a few amp ratings. Fuses can be enormous pains when they blow, and they’re such easy fixes. This step is much quicker than the previous method, but depending on where the appropriate fuse box is, you could get dirty.

Method 5: Disconnect a battery terminal

If you have the proper tools (and why wouldn’t you?), disconnect one of the battery terminals to do a sort of hard reset on the electronics system. Wait a couple of minutes, reconnect the terminals, and try to start the car. 


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