Clever Tricks to Solve When the Anti Theft System Car Wont Start

Anti Theft System Car Wont Start: What to Do?

What should I do when the anti theft system wont let my car start? It is possible that the system can trigger the car alarm or prevent the engine from running without any apparent reason. You have to shut it off if it is not working properly. The car won’t return to normal operation unless you fix the issue of anti theft device car wont start.

How to disengage anti-theft system? These tricks will help:

Check the battery

The first thing you should take a look into when the anti theft system car wont start is the car battery. It could be dead or low and needs charging. In that case, the car’s system won’t be able to read the security code off the key fob. Check the battery connections. If they turn out alright, try to jumpstart it. It is likely to solve the problem.

Battery could be the source of the problem. (Photo
Battery could be the source of the problem. (Photo Source: western61)

When you are inside the car

Apply this trick when you have access to the car’s interior and the ‘Theft System’ light on the dashboard is ON. Insert the key in the ignition slot and turn it to the right only slightly. Keep it in that position for 10 minutes or a little more. It is likely to turn off the light and start the car.

Remember that this is the state where the vehicle is on but the engine is off. All the necessary components like the radio and dashboard lights will be powered up, which makes it possible to bypass the theft alarm.

Reset the car’s computer

It is another way to solve the problem of anti theft system car wont start. Disconnect the positive terminal of the battery for a minute or two. Reconnect it and make sure that both the anode and cathode terminals are tightly attached. It will reset the computer system and your car is likely to kick off.

In case the trick fails, reset the factory alarm by activating its built-in kill switch.

Use the key trick with the steering wheel

Sometimes, the anti-theft system locks the steering wheel and does not let the key turn inside the slot. This annoying problem is mostly exclusive to Hondas. It mainly happens when you move the steering wheel after turning off the car. It locks the wheel in that position and does not let you move it next time you try to switch on the car.

Move the wheel and keep trying the key. (Photo Sou
Move the wheel and keep trying the key. (Photo Source: scoop)

The wheel is likely to be locked in one direction. Try moving it to the opposite direction and it will budge. Try pulling the car in that direction. At the same time, insert the key into the ignition slot and attempt to turn it. If the key is stubborn, pull on the wheel harder as much as possible and keep trying with the key. At one point, you will be able to switch on the ignition and start the engine.

Check the key

The key itself could be the culprit for the anti theft system car wont start. The keys have a built-in chip that sends a code to the alarm system when you insert it into the ignition. That chip won’t work in case of a broken or damaged key. If one key does not respond, try the other one. If nothing happens, take them to the dealer to scan of their transmission system is working.

Another trick you can try is to use the key to start the engine. If the engine does not respond or dies immediately after cranking up, leave the key in that position for 10 minutes. When the security light goes off, turn the ignition off, wait 20 seconds, and then start the engine.

These are the most popular ways to solve the problem of anti theft system car wont start. Most of the cars are likely to respond to at least one of these tricks.


Toyota Lexus Immobilizer Reset

We called the dealer here is their response: Lock the car and shut all doors, then use the key to unlock the driver’s door. Push and hold down the panic button on the remote. With no one in the car lock and unlock the car using the key remote. Disconnect the battery and reconnect as a last resort.

Step 3: Turn the Ignition On

Many immobilizer systems need to see the power utilized from each power input delivered from the ignition switch. Insert the ignition key and turn it to the on position and then attempt to start the engine (crank over), the engine wont start. With the key still in the run position wait 10 minutes and the security light should blink and then go out. Turn the key off and wait 5 seconds. Repeat these steps for a total for 3, 10 minute cycles. The car is now ready to relearn the Passlock code the next time the key is used, any trouble codes will clear after 100 cycles of the key.


What is an Anti-Theft System?

Modern cars all come with some form of the anti-theft system – but the one that will keep your vehicle from starting is the electronic immobilizer anti-theft system. 

Several countries mandated that manufacturers installed immobilizers on all new vehicles in 1998 – and since then, they’ve become standard on just about every vehicle.

The Economic Journal reports that they have reduced car thefts by 40 percent since 1995. Nowadays, they are so common that every new car in the United States has them.

Disconnect the Battery

Disconnect the Battery
Disconnect the Battery

One last thing you can try if your car alarm is going off and you can’t get it to stop, but you can get under the hood is to disconnect the battery. By unplugging the battery for a few minutes, it will also reset the computer. All you have to do is disconnect the positive or negative terminal and wait. After waiting a few minutes, you can reconnect it and see if that has solved your problem.

How to turn off your dashboard security light

If your security light is on and you can’t turn the car on, start by trying another key. In most cases, the security light means that the car no longer recognizes the key you’re using, so you may be able to bypass the problem by using a different key.If a second key doesn’t fix the issue and the light is still on, call a trusted mechanic to help you identify the issue and reprogram the anti-theft system. 

Method 1: Check the cylinder and key

Step 1: Check the battery on your fob. It is fairly common for the anti-theft system on a car to activate if your key fob is dead – a dead key fob is one that your car cannot “see”. Keep in mind that your key fob might not be dead, but the battery is simply not installed correctly.

Step 2: Check the door lock cylinder. If your vehicle has been damaged, during an attempted break-in or theft or otherwise, the anti-theft system might have been triggered. Check to see if the lock cylinder is damaged, and also check underneath the door handle – thieves have been known to use screwdrivers in an attempt to jimmy the door open.

If you find that the lock is damaged, the passenger side cylinder can also be used to shut off the anti-theft system.

Step 3: Check to make sure that you are using the right key to get your car started. It may seem ridiculous, but many vehicles have a valet door or key that performs only the function of unlocking a door. Though valet keys can unlock your door, they do not have a chip, and therefore cannot start your car.

Tip: Valet keys frequently have a different colored head, or a “V” inscribed on the key shaft.

Second: Know your key fob

Automakers pack a ton of features into key fobs, including some that might not be explained in the owner’s manual. Example: You can start a 2021 Chevy Tahoe with a key fob that doesn’t contain a battery by putting the fob in the driver’s side cupholder. You can roll all the windows up and down on a 2012 Honda Accord while outside the car if you learn the proper buttons and key placement, same goes for a 2018 Honda Pilot.

Learn what the key fob can do and learn how to get the physical key out of the fob. This also means learning where the mechanical lock is on your door and how to access it. The lock is often hidden behind a faceplate to keep the door handle pretty.

Yes, this is homework, but doing your homework is better on your couch than in a cold parking lot at 2 a.m.

The Car Alarm Vs. The Anti-Theft System

While technically the car alarm is an “anti-theft” system – it’s not what we’re talking about here.

 Car alarms might be loud and useful for scaring off burglars, but they work better to prevent the theft of the things inside of the card than the car itself. In fact, even if the car alarm is going off, you can still get it started, provided you have the proper key, and the electronic immobilizer anti-theft system is working correctly.

Meanwhile, the immobilizing anti-theft system won’t make a sound, but it will keep a potential thief from taking off with your car. On the flip side, the system tends to act up, so it can keep you from getting the engine started.

Troubleshooting a Faulty Anti-Theft System

Just like every component in your vehicle – if it works now, at some point it can break; the same applies to an anti-theft system. While anti-theft systems are pretty reliable – occasionally they’ll act up, and it’s important to know what to do if something like that happens to you. 

How to Identify a Fault Anti-Theft System

Before diving into the anti-theft system to figure out what’s wrong, you need to verify if what exactly is the problem! 

If your anti-theft system is acting up, you won’t be able to start your car. Furthermore, you’ll notice a light with either a lock or a key on your dashboard (depending on what you drive). This is your security/anti-theft light. Sometimes your vehicle’s ECU will illuminate this light in conjunction with your check engine light.

This light can appear l even if the key is the problem – since it’s not picking up the transponder code. It will turn on when you try to start the car – even if everything in the system is working correctly!

Always Start with The Battery

Whenever you’re troubleshooting an electrical problem, start with the battery. Your vehicle might trigger the security light because the receiver isn’t getting enough power – and that is also probably why your car won’t start.

Bad or dead batteries are one of the most common reasons for a “faulty anti-theft system.” They’re also one of the most manageable problems to fix, but also one of the most overlooked. You can spend days chasing your tail if you don’t start with the simple things!

Reset the System

If you’ve checked the battery and everything looks normal, the next thing you should do is reset the system. This might sound hard, but it’s actually one of the easiest things you can do.

All you need to do is disconnect the positive terminal from the battery and leave it off for about 15 minutes before reconnecting. This resets your entire vehicle’s electronic components – including your anti-theft system.

This might not seem like it’ll do much, but if your vehicle’s anti-theft immobilizer does get tripped, sometimes it won’t reset unless you reset the entire system.

Check if the Steering Wheel is Locked

If you’re inside the car and can’t get the key to turn at all – it might be because the steering wheel is locked. Typically, this happens after the steering wheel, someone or something slightly turned the wheel after the key was out of the ignition.

This problem is more annoying than anything else and is relatively easy to fix – even if it does take a bit of persistence. 

All you need to do is wiggle the steering wheel around a bit until it loosens up. You’ll feel the noticeable difference. Sometimes you might need to turn the key in the ignition while trying to turn the wheel to get it to loosen up.

Take a Closer Look at Your Key

It’s the easiest component to see and the easiest to check for glaring defects. Each key has a transponder – and if that transponder is broken or missing, you won’t be able to start your car.

If you see anything wrong with the key, you’ve likely found your problem. If you have a spare key, this is extremely easy to check. 

Simply try starting the vehicle with a spare key after you’ve reset the system. If it starts, you’ve found the problem!

You’ll need to replace the key – as most manufacturers won’t fix just the transponder chip.

Read the Code!

If you’ve completed the previous steps and yet you still struggle with the anti-theft system, it’s time to read the code. 

Just like a check engine light, a code reader will tell you why the light is on. It might be that the receiver isn’t getting a signal from the key, or it might be that your receiver isn’t getting any power.

A code reader won’t tell you what you need to replace – but it’ll point you in the right direction.

Troubleshoot and Replace the Highlighted Component

This is where things get a little more complicated – since there are tons of different codes, there are tons of troubleshooting trees you could follow.

But when troubleshooting, keep the basics in mind. If you know how the system is supposed to work, you can’t reason out why it’s not working based on the code’s data. If the receiver isn’t getting a signal, it’s one of two problems – the receiver or the transponder.

Either way, you’ll need to get a key to match the new receiver – so you might as well save a little time and replace both components.

However, if a lack of power is your issue, you’ll need to dive into your electrical troubleshooting – or take it to a mechanic.

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