My Car Anti Theft System Is Not Letting My Car Start?

My Car Anti Theft System Is Not Letting My Car Start?

One of the ways to describe the situation where your car anti-theft system is refusing you access to the car is like your pet that no longer recognizes you. That’s no fun for sure. Most new cars come with a pre-installed anti-theft system, or you can install some version of a car theft deterrent that can be as simple as an alarm.

Whichever the case, the purpose of an anti-theft system is to deter automobile thieves from accessing or stealing your vehicle. Most anti-theft systems are designed to trigger intermittent flashing of the head and taillights accompanied by a sound alarm whenever the car detects suspicious activity. Suspicious activity could mean someone trying to open your car without the original key or key fob.

Car anti-theft systems are such fantastic technology until it starts malfunctioning leaving your car unable to start. It has never been fun for your own car to treat you like you’re the thief it’s guarding against. No worries though, this article will show you what you can do if you ever found yourself in such a situation, leaving you feeling like a man whose dog can’t recognize him anymore after a long trip.

Why Is It Happening?

If the anti-theft light is flashing and your engine refuses to start, either one of these two is going on; there was an attempted breach or the system has developed a fault(s). Issues with car anti-theft systems include:

  • Failure of the anti-theft system to recognize your key or keyless entry signal
  • The battery of the key is dead, or there is a fault with the chip in the key fob. Problem key fob chip won’t let you get in the car, to begin with.
  • Your car’s anti-theft system is picking up wrong signals. This is more common in cases where you have two or more smart keys on the same key ring.

Your vehicle could randomly pick up signals from another smart key, preventing your engine from cranking up. Other times, it might lose signal from the original smart key, and pick a new signal from another key while driving, causing your engine to stall. If you happen to be experiencing any of this, you can bypass the system to relearn it.

What Can You Do?

Now, let’s take a quick look at what you can do if your car’s anti-theft system is refusing you entry to the car or preventing the car from starting.

  • 1st Scenario: You don’t have access to your car’s interior because your system is not recognizing your smart key

Do this: Insert the key in the driver’s side door and turn it like you would if you wanted to unlock the door, and then hold it in place for a few seconds. This strategy allows your car’s anti-theft system to confirm that you have the original key. If the system still does not give you access after doing this, check to make sure that your smart key battery isn’t dead. If you have a spare key, you can try this same method to see if the system is transmitting.

  • 2nd Scenario: You have access to your car’s interior but your engine isn’t starting up

Do this: Try the passlock relearn procedure. The passlock relearn procedure is a 10-minute procedure that involves trying to bypass the anti-theft system and start the engine. Here’s how to perform a passlock relearn:

Attempt to start the engine like you normally do, then leave the key in position for 10 minutes. The anti-theft light would remain on for a while on your dashboard and then disappear. After the light has turned off, turn the ignition off and wait twenty seconds and then restart the engine. If the engine starts and runs, then you’re good to go. But if the engine doesn’t start at all or starts and dies, then it’s time to try the 30 minutes relearn procedure. The 30-minute passlock relearn procedure is the 10-minute procedure repeated thrice. After the third attempt, the engine should be running.


Factory-fitted car anti-theft systems generally do a better job of protecting your vehicle from thieves and people with nefarious intent but their higher reliability also means they are harder to bypass. Such factory-fitted anti-theft, especially VTD (Vehicle Theft Deterrent) models, not only prevent the engine from starting, but also disables the fuel system and starter whenever it detects suspicious activities.

Nevertheless, attempt the relearn procedures outlined above if your anti-theft system is refusing you access or control of your car. If all else fails, contact your car dealership to help resolve the issue.

Leave a Reply

Required fields are marked