What Do the Immobilizer Warning Lights Mean?

A vehicle can be a big investment so it is important to make sure that no one can take your car without your keys. Nowadays, almost all vehicles have inbuilt immobilizer systems which prevent the engine from starting unless the correct key is being used.

Early systems had a simple code stored on the key which was read by the computer while trying to start the engine. Now, more advanced methods of encryption are used, so it is much harder to trick the system these days. The overall idea is the same though, whenever you turn the key, the car’s computer reads a code from the key and checks it against the codes that are currently known. If the computer finds a match, it will let you start the engine.

If a key match is not detected, a few things can happen. The engine may start and run for a few seconds before dying or the engine may not even turn over at all. A warning light is included on the dash to let you know how the system is reacting.

What the immobilizer warning light means

The indicator for the immobilizers behave similarly between different vehicles, but refer to the owner’s manual for specific information on your vehicle’s system. Generally, when you first start the engine, this light will illuminate for a few seconds showing that the correct key has been used. If the computer doesn’t recognize the code on the key, the light will flash multiple times. You won’t be able to start the engine until you use a recognized key.

If you have a keyless ignition in your vehicle, make sure that the key is close enough to register with the receiver inside the car. Even if the key fob has low or no battery power, most vehicles have a backup procedure so that you can still start the car. Information on this procedure will be included in the owner’s manual.

All vehicles can have multiple codes registered at a time so that you can have multiple keys to use the car. A factory scan tool or an already known key is needed to teach the car new codes.

Is it safe to drive with the immobilizer warning light on?

This warning light usually only comes on when the key isn’t recognized so you shouldn’t have to worry about this light coming on while you are already driving. If this happens, try taking the key out and reinserting it if you are having trouble getting your car started. If you are experiencing any troubles, check and verify that the key fob isn’t out of power.

If your car’s immobilizer system isn’t working properly, our certified technicians can help you diagnose any issues you are encountering.


Next Step

Schedule Warning Light is on Inspection

The most popular service booked by readers of this article is Warning Light is on Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent Warning Light is on Inspection reviews

Excellent Rating

(238)

Rating Summary
224
5
4
0
5
224
5
4
0
5

Jason

15 years of experience
344 reviews
Jason
15 years of experience
Nissan Armada V8-5.6L - Warning Light is on - Mineola, New York
Excelente. Jason es todo un profesional con mucho conocimiento en la mecanica, buena persona educado y amigable. Gracias Jason.
Ford Taurus - Warning Light is on - Jamaica, New York
Very Professional definitely takes his time to find out exactly what’s the problem with the car! I was up and running in no time ! Will definitely recommend Him to anyone having issues with cars!!!

Nicholas

11 years of experience
585 reviews
Nicholas
11 years of experience
Chrysler 300 V6-2.7L - Warning Light is on - Durham, North Carolina
Excellent diagnostician. Knowledgeable and caring. Created a desire for him specifically, to do the job. Hope we get him every time!
Honda Accord - Warning Light is on - Garner, North Carolina
I was very happy with Nicholas and his knowledge and expertise about diagnosing the issues with my car. He is honest, reliable and professional. He is now my Mechanic that I will call on for all my car's needs.I will also recommend him to my friends whom have been taken advantage of by other car shops as I have been, and are looking for someone honest , that will not take advantage of them Thank you so much Nicholas for resolving my issue with my car. I feel relieved and happy with the outcome

Tony

40 years of experience
12 reviews
Tony
40 years of experience
Cadillac Escalade EXT V8-6.2L - Warning Light is on - Stockton, California
Good,mechanic helpful ,smooth move but quick, friendly patience and deep experience as a mechanic,as a customer I recommend Tony Crockett if you need a mechanic.

Brent

8 years of experience
56 reviews
Brent
8 years of experience
Jeep Grand Cherokee V6-3.7L - Warning Light is on - Lithonia, Georgia
On time for appointment. Knowledgeable, he explained what he was doing & then explained his findings to me. Later he sent a text with the diagnostic findings,

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

What Does the Lane Departure Warning Light Mean?
The lane departure light means the vehicle is detected to be moving out of its current lane without signaling. It may assist to keep you in your lane.
What Does the Power Steering System Warning Light Mean?
The steering system warning light lets you know when there is an issue with the power steering system and will be disabled until fixed.
What Does the Trailer Tow Hitch Warning Light Mean?
The trailer tow hitch light is designed to warn you when there is an issue with your car's tow hitch, possibly that it is unlocked.

Related questions

What does the Charging System warning light mean?
The Charging System warning light is located on the instrument panel, and is connected to the battery. When the battery is not charging properly, the light will illuminate. Tip Like all warning lights, the Charging System warning light briefly illuminates...
ABS & SRS lights on; car shifts hard and shudders
Hi there. These repairs that were done are fairly normal for this vehicle. It is very common for this car to have issues with these systems with age. I am actually a little surprised that there were not more issues...
Honda CRV 2005 VSA light on car is shaking while driving
Hello, thank you for writing in. The VSA (vehicle stability assist) light comes on steadily when there is a problem. If it blinks, it means the system is actively working to control the car and help it steer. If the...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com