Anti Theft Light On While Driving: Why & How To Fix

The anti-theft system on cars helps warn of thieves who want to steal your car and equipment when the car is parked in areas where there is no security guard. However, on a nice day, anti theft light on while driving? What can you do next?

Anti-theft systems can misfire and cause a lot of bothersome problems, though. Your car can have trouble starting. 

Alternatively, the system can abruptly turn off the ignition while you are driving, which would cause your car to stall. The alarm can ring in addition to going off if you use the key to unlock the door. The alarm could sometimes go off for no apparent cause.

When the anti-theft light comes on while you’re driving, you should pay attention to it. Discover the cause of and solution for the anti-theft light’s persistent on-state. This issue is thoroughly covered in this article.

What is a Theft System in Vehicles

A car anti-theft alarm system is a type of security device that aids in the protection of vehicles when signs of theft are detected. 

The car anti-theft system typically protects the vehicle by emitting alarm signals via horns and lights, preventing the vehicle from starting, and sending a notification to the vehicle’s owner… 

There are several theft prevention systems, but the majority function by identifying the key. The system will prohibit the engine from starting if the incorrect key is used. Using the incorrect key might also trigger an alarm on some systems.

An alarm system is yet another common anti-theft device. When someone tries to break into your automobile, alarm systems generate a loud noise that should frighten the intruder away. 

Some alarm systems also have capabilities that, in the event that the alarm is activated, will disable your car, making it more difficult for the thief to drive off with your vehicle.

Not every car has an integrated theft prevention system. However, many more recent cars do come equipped with some type of anti-theft technology. 

These gadgets may include things like tracking devices, alarm systems, and engine immobilizers. If your car lacks an inbuilt theft deterrent system, there are aftermarket alternatives that you may buy and install yourself.

Anti Theft Light On While Driving: Why?

The anti-theft light is designed to keep your automobile from being stolen; if it remains on, a system issue is present. The light, though, may turn on for reasons beyond deterring theft. It would be wise to consult a professional as soon as possible to get this examined.

The fact that your car’s computer does not recognize the key you used to start it is one of the reasons the anti-theft light remains on. 

The receiver may not be able to read the key because it is too worn, or it may have a problem of its own. An engine light or an indicator lighting for a malfunction may be included in addition to this.

Your car’s battery can be failing, which is another factor contributing to the anti-theft light remaining on. Defective alternator diodes, loose connections, or terminal corrosion can all contribute to this. An engine light or a fault indicator lamp may also be present (MIL).

Can You Leave Anti-Theft Light On While Driving?

The anti-theft light cannot be left on while you are driving. The basic justification for this is that if the light is on, you won’t be able to start your automobile. You must first turn off the anti-theft system before starting the engine.

This security measure stops thieves from stealing or hot wiring your car. They can’t get around security systems that have an anti-theft system in place unless they first disable the anti-theft system.

How To Fix: Anti Theft Light On While Driving

Don’t freak out if you see your theft system lighting up while you’re driving! Here’s how to reset your car’s theft deterrent system.

Check Your Car’s Issue Codes

When your theft system illuminates while you’re driving, the first thing you should do is scan your car. You must do this by connecting your scanning device to the OBD port under the steering wheel.

Vehicles may display a number of various theft system-related problem codes. An issue with the vehicle’s immobilizer system is indicated by the code P1629. 

In most cases, this code denotes a problem with the transponder key or the transponder key coil.

Another code associated with the immobilizer system is P1630, and it often denotes a problem with communication between the transponder key and the ECM.

Last but not least, the P1631 code denotes an issue with the ignition key lock cylinder of the car. Usually, this code denotes a problem with the ignition switch itself.

However, keep in mind that the theft system won’t always provide you with fault codes. The theft system can occasionally malfunction without sending any issue codes.

Reset The Theft System

When you scan your car and find no issue codes, yet the theft system remains flashing while you’re driving, it implies that your car has entered what’s known as a learning mode. When your car is scanning and attempting to identify the key, it is in a learning mode. 

The car can enter learning mode using various mechanisms. Your car will require some time to learn and recognize the key after the theft system activates the learning mode, though.

Your vehicle can be taken out of learning mode and the theft system reset. You must put your key in the ignition and turn it to the ON position five times in less than five seconds in order to reset the anti-theft system.

You can reset the anti-theft system in your car by twisting the key five times in five seconds from the off position to the on position. After that, starting your car won’t be a problem for you. 

You won’t have that problem any more if the theft system was lighting up while you were driving.

Key Reprogramme 

If you can’t get your car to start and your security light is flashing on the dashboard. Your key will need to be reprogrammed. System keys that have been stolen differ slightly from standard keys. 

They contain a transponder chip that communicates with the car’s computer. This signals to the vehicle that the key is valid for starting the engine. For some reason, the car eventually forgets and no longer recognizes the key.

Put your car’s key in the ignition and turn it to the ON position to reprogram it. Ten to fifteen minutes should pass with the key in the ON position. Your car will relearn the key during this time so that it will recognize it the next time you try to start it.

When the security light on the dashboard stops flashing, the vehicle’s computer has successfully reprogrammed the key. Turn the key to the OFF position once it stops flashing, then try to start your car.

Read more: Toyota Corolla Car Alarm Keeps Going Off – How To Fix?

Will Anti Theft Light Drain The Battery?

The battery won’t often discharge too quickly with most factory-installed auto alarm systems, but this isn’t always the case with aftermarket alarms.

This is particularly true for alarms that have a setting for “on” while the ignition is off and the car is stopped.

Because the battery in these systems is wired directly to the alarm, the battery eventually loses power. The battery could eventually stop working as a result of this.

Overall, the battery can be discharged by the anti-theft mechanism. When you bring it to a service facility, you can check this.

Frequently Asked Questions

Q: How do I disable the anti-theft system?

Your accessories will be turned on when you place the key in the ignition and turn it to the “on” position, but the engine will not start. Keep the key in place for 10 to 15 minutes. Step three is to double-check the anti-theft light. When it stops blinking, flip the key back to the Off position and give it a few minutes to settle.

Q: How much does it cost to fix an anti-theft system?

Replacement of the control module for an anti-theft system typically costs between $411 and $438. The cost of labor is expected to be between $104 and $132, while the cost of the parts is $306. This range does not account for taxes and fees, your particular car, or your particular location.

Q: How long does it take for the anti-theft system to reset?

For 15 minutes, leave the key where it is. It can take that long, however it doesn’t always. Once that period has passed, see if the anti-theft light, if one was lighted, is still on. Wait three more minutes after reversing the key two positions to the Lock position.

Final Thoughts

After reading our explanation, we hope you now have the response to your query. Simply leave a comment below if you have any additional queries, and we’ll do all in our power to assist you.

Leave a Comment

Read more