How to Tell If Your Car Has a Transponder on it

by James Rutter

A transponder is a communication device that consists of two parts: a transmitter and a responder. These devices broadcast and receive signals and can be built small enough to fit inside of an inspection sticker or the head of a car key. You may have one in your car for a number of reasons.


Find out if the manufacturer installed a transponder. Some car manufacturers have started installing transponders inside the ignition key. This serves as an anti-theft device. When the key with the transponder is inserted into the ignition, the transponder sends a signal to a receiver in the engine that tells it to start. Your car manual will list whether or not one of these devices has been installed in your vehicle.


Ask the human resources department of your company if they have installed a transponder on the company car you are driving. Your company may have installed a transponder for any number of reasons: as an anti-theft device, to track mileage or to track the hours the car is being used.


Check your glove compartment to see if you own an EZ Pass. State toll highways such as turnpikes that offer EZ Pass pay systems (or any similar system) utilize transponders in the “pass” itself. If you have signed up for an EZ Pass in your state and they mailed you a kit to keep in your car, you have a transponder. This device allows the tollbooth to read your transponder and bill you each time you use the state toll road.


Ask the homeowner's association where you live. If you live in a gated community that requires you to pass through an electronic gating system whenever you leave or exit the community, you may have a transponder in your car. Some gated communities use transponders to recognize the vehicles owned by residents; when a resident’s car approaches the entrance, the transponder signals to open the gate.


Locate the transponder on a racecar by checking inside the rear center of the frame. Some racetracks now use transponders to track the speed and position of the cars during a race. If you own a customized vehicle that you race competitively, it may have a transponder for that reason.


Call the Department of Motor Vehicles of your state. In 2005, the State of Texas proposed placing transponders inside of the inspection stickers of every car registered and inspected in Texas. This device would signal police cars or stationary receivers along a roadway whether or not your car had a valid inspection and/or was properly insured. If you are unaware of whether or not your state might have passed such a law, call the DMV.


Contact your car finance company. Depending on the conditions of your car loan, your finance company may have installed a transponder on your car in the event of non-payment or for repossession. This device would allow the company to disable the ignition switch of the car in the event of non-payment.

Items you will need

About the Author

Since 2005, James Rutter has worked as a freelance journalist for print and Internet publications, including the “News of Delaware County,” “Main Line Times” and Broad Street Review. As a former chemist, college professor and competitive weightlifter, he writes about science, education and exercise. Rutter earned a B.A. in philosophy and biology from Albright College and studied philosophy and cognitive science at Temple University.

More Articles

Photo Credits

  • photo_camera Jupiterimages/ Images