Home Security Systems Engine Immobilizer: Everything You Need to Know In 2022

Engine Immobilizer: Everything You Need to Know In 2022

by Kelvin Yates

The engine immobilizer is a theft deterrent built into the engine control unit (ECU). It makes it hard to start your car’s engine unless the correct key is used. The system employs a one-of-a-kind key. The manufacturer then embeds a transponder chipset into the car key, which is responsible for storing the digital code for the engine. The engine won’t start until the transponder chip’s code matches the immobilizer’s.

Your car’s anti-theft system works with the immobilizer to produce this top-notch security. The engine management system interacts with the computer control system the moment it detects the passcode from the digital key. Your car is far less likely to be stolen if the security system is functioning properly.

Engine Immobilizer System


The engine immobilizer mechanism built into recent cars from top brands like Lexus, Mercedes-Benz, and BMW employs both static and changing security codes. BMW’s Two-Tier security system is standard in all their recent vehicles. They usually come with a private code that never changes and a secondary code that varies.

It updates the secondary code every time you start the engine or enter your vehicle with the key fob, and it writes the new code version into the key or key fob. It means that if someone shorts out the ignition circuit and tries to start the engine, it won’t work without the second security code.

The key will transmit a digital token to the immobilizer to unlock the vehicle’s ignition whenever you start the car. It also creates a new security code, and only your key can give the right token for your car. Your car will not start if the key is not genuine or a key fob or chip is missing. That means you can’t use your car if you misplaced the key fob or chip.

Engine immobilizer systems generally stop people from stealing cars. It’s a very powerful system. However, certain security experts have recorded some loopholes in the system recently, like most security systems.

Are Car Immobilizers Sufficient For Car Security?

Engine immobilizers have had a favorable impact on auto theft rates. However, certain criminals work harder than others to circumvent these devices. With the ever-increasing dangers posed by hackers, car owners have the option of adding another layer of protection.

Many criminals are keeping up with the trends around engine immobilizers and figuring out new methods to hack the transponder codes and start autos. But, not all criminals are good with technology or know their way around hacking. To further boost your car’s protection, I’d suggest installing a steering wheel lock, an extra alarm, or a kill switch.

Bad Engine Immobilizer Symptoms

1. Door Unlocking Problems

Nothing happens when you try to open your vehicle’s doors remotely using your key. This makes it almost impossible to access the interior of your vehicle. Because the doors of many newer cars do not include keyholes on the outside, you can’t physically unlock them with a key in many cases.


You may have to hire a locksmith or a tow truck will be required while you wait for professional assistance. However, before carrying out any action, ensure you always double-check the installation of the batteries in your key fob to make sure everything is working properly.

If that inspection is successful and the door remains hard to open and shut, think about getting assistance from a qualified auto lock specialist. Also, some difficulties with unlocking and starting a vehicle could result from the failure of an entire car key system.

2. Door Locking Problems

It’s likely that if you can’t open your door using a key fob, you can’t also lock your door. You can only lock your car from within once you manage to enter. You’d be putting your vehicle at risk from burglars, vandals, and bad weather if you can’t have the issue fixed.

However, even if you managed to lock it from within, you won’t be able to regain access to your car if you don’t get your key fob or transponder fixed. Bad key fobs prevent the immobilizer from receiving the signals, rendering the car inoperable. Look for a local locksmith or have it towed to a repair shop to get it back in working order.

3. Dashboard Indicator Not Going Off


There is a dedicated light on the dashboard of certain vehicles for the engine immobilizer system. Your key is not working if the light doesn’t go out after a few seconds, like 3 seconds after switching the ignition. Consult your manual to know what the indicator looks like for your car.

Also, many newer cars have digital dashboards linked to the ignition. The dashboard won’t function when locked out by a faulty engine immobilizer. If that’s the case, your car’s engine immobilizer is either bad or not receiving signals from the transponder chip. Follow the steps listed below to get it fixed.

4. Engine Does Not Start

One of the signs of an engine immobilizer issue is that your car won’t start in the first place. The problem may lie with either the key transponder or the engine immobilizer. Ensure that you are using the right key fob for the car before settling on a possible cause. Using the key fob of a similar car brand does not guarantee it will match yours.

Another factor that might stop your engine from starting could be water or moisture getting into the circuitry. That will probably cause significant damage to the immobilizer, leading to system failure. The immobilizer wiring could be faulty if you’re experiencing engine issues that have no other logical or technical explanation.

If your car has a push-button starter, try starting it by pressing the button on the key fob that’s attached to the ignition. Should it work, fine; if it doesn’t, it’s still a win-win situation, since you’ve nailed down the root cause of your issue. Call for a repair from the professionals.

5. Car Alarm Problems

There is a link between your car’s alarm system and its immobilizer. They are both connected and work together to provide maximum protection for your vehicle.

If the immobilizer doesn’t function correctly, the alarm system won’t work correctly. That would mean your car alarm system not triggering if criminal impacts or shatters your car windows.

6. Key In Ignition Does Not Turn

Any problem with the transponder chip may result in the key not turning when you insert and spin the physical key in the ignition. For some reason, the immobilizer in the car is not receiving the security code. When that happens, water has likely damaged the fob or you have a broken chip.

Possible Fix for Engine Immobilizer Problems

Most of the causes of immobilizer problems would result from a faulty or malfunctioning key fob. The engine immobilizer system hardly fails except when it has to deal with corroded wire.

car safety alarm anti theft

1. Replace The Dead Key Fob Battery

Your key fob uses a 3V battery. It usually begins to drop in receptivity when the battery power starts to drop. If the battery is not changed, the key transponder chip will not send the signal to the engine immobilizer system. Follow this guide to replace your key fob’s battery.

2. Fix Damaged Key Fob For The Engine Immobilizer

Your key fob is likely to damage when submerged in water or if it experiences an impact that damages the transponder chip. When that happens, your key won’t transmit the digital code to the engine immobilizer system for processing. That would likely result in some of the symptoms listed above. You’ll have to contact your dealership for a key fob replacement. The price costs a few hundred dollars and would vary by car model.

3. Check For Bad Connections In The Engine Immobilizer

If you’ve tried replacing the key fob battery or opted for a replacement and the problem persists (and you need to worry about changing batteries in the key fob), it could be from the car’s immobilizer system. Check its wiring. An immobilizer system may malfunction or is likely to fail soon if you see rust, damage, or other signs of wear on the wire. Fix the wiring at the dealership to correct this issue.

4. Replace The Engine Immobilizer

It’s also possible that your car’s immobilizer itself is bad. Replace it yourself if you know the way around it, as that will save you some extra replacement costs. Before you start, go through your vehicle’s service manual to understand your vehicle’s internals.

Get the work tools ready, like the wrenches, screwdrivers, and wire cutters. Unfortunately, there is no one way of replacing engine immobilizers for all cars, as that would vary by vehicle model. Follow the manufacturer’s manual for repairing or replacing an immobilizer.

Before starting, disconnect the battery terminals. Some immobilizers would involve removing a screw. Meanwhile, ensure you install the recommended immobilizer for your car. Once done, reprogram your vehicle’s computer board to accept the new device. There are occasions when you have to hit several buttons consecutively to get the computer to recognize the new engine immobilizer.

5. Bypass The Engine Immobilizer System

car safety alarm anti theft

This is probably the last option for those after making their vehicle work. The process of bypassing the security system would vary by car model.

It’s as simple as disconnecting the immobilizer and joining some wires to make your car feel everything is okay. That is risky though, as your car will be exposed to theft. We don’t recommend this, but if your car is old, and it seems like that’s the last option, you may give it a try.

Another way of bypassing the system is by inserting the car key containing the chip into the car door. Turn the key either way, like you want to unlock it. Leave the key and wait for about 30 seconds for the security system to detect the code signals from the key. You should be able to use the vehicle after that. Try it over again if it doesn’t grant you access; ensure it’s with the original car key.

You can also perform an immobilizer bypass without a key by using the key fob close to your vehicle. Once your vehicle detects the signal from the key fob, it will unlock, and the car engine should start.

Best Engine Immobilizers In The Market

If your vehicle is not factory-fitted with an engine immobilizer, you can install one yourself. Some good car immobilizers exist today. Like the

  • EiQ-GPS Immobilizer,
  • Bosch Immobilizer,
  • JM Auto Systems M-Flex Plus, and
  • The Autowatch Ghost-II immobilizer

The Autowatch Ghost-II is a powerful immobilizer system that works with most cars. It is meticulously disguised in the wire loom of a vehicle to make it hard to discover and deactivate. It is the replacement for the first aftermarket CAN bus immobilizer. To find out how this system works, check out our guide on the U0073 code.

Autowatch Ghost-II works like it’s factory-fitted and uses the buttons already present in your car. It will require you to generate a customizable disarm sequence, similar to a PIN code, that you’ll use to unlock the car before use. It also comes with a smartphone app for easy unlocking without going through the hassle of manually entering the codes.

This immobilizer works with many vehicle models on the market. Aside from the excellent protection it provides, you will find it very easy to use.

Car Immobilizer Facts:

  • Most vehicles made in the last 20 years have a car immobilizer system, which minimizes the likelihood of car theft by preventing the unauthorized starting of the engine.
  • Car immobilizer technology uses key fobs or smart keys, which have transponder chips that communicate a passcode to the immobilizer system when starting the engine.
  • Immobilizers sound an alarm if the wrong code is used to turn the ignition, and some digital auto systems notify a security service if a theft attempt is made.
  • Some immobilizers have a two-tier security system with a fixed code and a changeable code, which is altered each time the car is started, making it harder to steal.
  • Car owners can check if their vehicle has an immobilizer by reading the car’s handbook, which should have all the information on the vehicle, or asking a skilled mechanic to inspect the car.
  • Immobilizers have decreased car crime by a significant amount since their launch, but thieves have found ways to bypass them, such as relay theft, which intercepts the code created by the car’s key and deceives the car’s electronics into thinking the key is present.
  • Thatcham is a non-profit organization that assesses a vehicle’s security, including immobilizers, to assist insurance companies in determining premiums.
  • A factory-fitted and Thatcham-approved immobilizer is the best option to make a car substantially safer and less risky for insurance companies, leading to a lower rate.
  • Car owners should still be vigilant and plan ahead for their car’s security, including parking in well-lit areas, keeping car keys secure, and being cautious when near their vehicle.
  • Immobilizers are a great piece of electronic security technology that act as a deterrent to vehicle theft and offer peace of mind for car owners.

Last Words On Engine Immobilizer

Engine immobilizers are powerful security systems that ensure your car remains safe while you are miles away from it. Even when broken into or stolen, the immobilizer system is essential to keep it protected. Classic ignition keys are being phased out in favor of proximity-sensitive key fobs, which are common in most modern automobiles.

Most car thefts in the US are done in the absence of the owner; that is where the engine immobilizer system comes in handy. It stops thieves from gaining access to the car or starting the engine. Besides, the technology also offers tracking capability. Hence, the police can find your vehicle within minutes should it go missing.

Frequently Asked Questions On Engine Immobilizer

Here are some popular FAQs:

What Is An Engine Immobilizer

This is an Anti-theft system built into the engine ECU to prevent the illegal use of a vehicle. It is right to think of it as an electronic safety system installed in a motor vehicle. The engine immobilizer system consists of the transponder chips in smart keys and the immobilizer receiver. If the immobilizer and the key codes match, the car starts. It won’t start otherwise; without clearance from the anti-theft system, the car won’t start. Making it almost impossible to steal a car; since it can’t be “hotwired” even when broken into.

How To Remove Engine Immobilizer

You may disable engine immobilizer systems in various ways, but the most common approach is to reprogram an EEPROM chip on the ECU. This requires the use of some special tools. Consult your vehicle’s manual before attempting to remove the engine immobilizer. If your vehicle is old, you may want to remove the engine immobilizer when you lose your car key. However, ensure to do it the right way. Some vehicles can initiate an emergency lock once it senses you are trying to circumvent the immobilizer system. You may wish to consult professionals or your car manufacturer to achieve that.

Immobilizer Bypass How To Disconnect A Car Immobilizer

It depends on the vehicle model and the type of immobilizer in question. Modern vehicles are smart; they can trigger an emergency mode once you attempt to bypass or disconnect the car immobilizer. It’s easier to bypass the car immobilizer systems of older vehicles; do the following – 1) use the door key to pretend to open the door. Then, leave the key at the door lock cylinder for a short amount of time. Now, the immobilizer unit needs at least 30 seconds to recognize that you have the right key. Finally, start the car. In this way, you will be able to circumvent the immobilizer system and turn it off.

How To Disable Anti Theft System Without Key

You can disable the anti-theft alarm if your key fob is damaged, misplaced, or not present with you at the moment. If your car alarm goes off, switch on the ignition and wait for it to stop. If it doesn’t, your best bet is to remove the fuse that powers it and disconnect the wires. Your owner’s manual is the best place to start. If you installed the alarm, it’s likely the cables are behind the steering wheel.

How To Start My Car Without Chip Key

For newer vehicles losing your chip key will make it hard to start and move the car. It’s better to opt for a new chip key from the dealership if you’ve lost your key or the chip is bad. Most manufacturers usually make backups for emergencies like this. Some vehicles have an emergency key fob with a passive RF chip. If the main chip key fails, this is a useful backup. Place the emergency key fob close to the start button to pick up the passive RF signals. Try starting the car again, and it should start. Also, smart keys also come with a mechanical key in case of an emergency. Use this mechanical key to spin the door lock’s keyhole. Other ways of starting your car without a chip key may involve hot wiring for older vehicles. You can also disable the lock pins using a hammer and a screwdriver.

How to Disable Transponder Key System Without Key

You can do that by using the key fob having the primary key chip. Come into a close range with your vehicle having the key fob, and the immobilizer system should detect the signals from the key fob. Once they are detected, you can then start the vehicle. If the immobilizer light on the dashboard keeps flashing, it’s likely the key fob battery is down and unable to transmit the signal. Replace the battery and try again.

How To Get Car Out Of Anti-Theft Mode

Most cars will trigger the anti-theft function once you try to tamper with the security system. Hence, the need to reset the immobilizer system before using it again.  The general way to reset the immobilizer systems of some car models like ford and Toyota involves using the car key. Simply switch on the ignition (not the engine) and wait for about 15 minutes for the anti-theft light to switch off on the dashboard. Once the light is done blinking, switch off the ignition. Wait for the engine immobilizer to detect the key and reset the system. (It will usually take about 3 minutes). After that, start the engine. The car should work now. If it doesn’t, repeat the process again. It should work if the car battery is in good shape. You can get some newer vehicles out of the anti-theft mode by holding the panic button on the key fob for a long time.

How To Remove Immobilizers From ECU

The most common approach to removing the immobilizer from ECU is to reprogramme an EEPROM chip on the ECU. Almost anybody can do that using the right tools. A wide variety of immobilizer-disabling tools are now available, allowing you to choose the one that best suits you.

What Triggers Theft Deterrent System

The theft-deterrent system will trigger when you try to forcefully access the car through the door, trunk, fake key, or by breaking the glass. The alarm system will also trigger, and the vehicle will lock. With the service theft deterrent system, the car won’t start until it detects the digital signal from the transponder chip.

How Do I Know If My Car Is In Anti Theft Mode

You will know that your car immobilizer system is working if it performs its basic function of locking and unlocking your car. It is working as long as the immobilizer light on the dashboard comes on and goes off the moment your vehicle starts. Anything other than that should be a fault. A bad immobilizer may not allow you to open your vehicle door or start the engine even if you manage to bypass the door.

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