What is the "confidential vehicle identification" number?

What cars bear that and where is it located?

  • I've never heard of one, unless it has to do with aftermarket etching or some such. Only real ID on a car I'm aware of which comes from the factory is the VIN ... I could be wrong, though. It is hard to prove a negative. Apr 23, 2015 at 21:49
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    Where did you hear about this, and in what context? Apr 23, 2015 at 21:55
  • Are you asking about other locations where the factory serial (VIN) is located besides the base of the windshield?
    – mikes
    Apr 23, 2015 at 22:06
  • Never heard of that either. Is this something that might be particular to a certain manufacturer of car? It seems strange to put another number on a car when it already has a unique one. You can use a VIN as a stock number or any other type since it's unique. Doesn't make much sense, probably because there's no background info. Apr 23, 2015 at 23:44
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    I heard about this from someone working at FBI. He said even if the normal VIN is destroyed, a vehicle may still be identified by the "confidential vehicle identification number" for criminal investigation purposes. Another mentioning of it in Wikipedia: en.wikipedia.org/wiki?title=Talk:Vehicle_Identification_Number
    – qazwsx
    Apr 24, 2015 at 9:22

4 Answers 4


I found some excellent information on Confidential VIN, as follows...

Hidden or Confidential VIN

VINs have been stamped into frames of vehicles for many years, however the process became more uniform starting approximately during the 1968 model year. The VIN was stamped into various metal objects on the vehicle, including the frame, the body, the engine, transmission and other places. The VIN on the frame or the body became known as the Hidden VIN, the Confidential VIN or the Federal VIN. This number is usually not a full, complete VIN but a derivative thereof. The sequential production number of the hidden VIN should match the sequential production number (the last five or six digits) of the Public VIN and if the vehicle was produced after August 31, 1969, the FMVSS certification sticker. The VIN on the engine and transmission would have also been a derivative of the VIN and it too should match the Public VIN provided that the engine and/or transmission is original.

Full article here


A confidential vehicle identification is just a VIN in a hidden place that is only known by the manufacturer and law enforcement. It is used to thwart car cloning.

Examples of this would be a VIN stamped into the wheel arch liner, ashtray, on the floor under the spare tyre , etc - i.e. a non-obvious location.


A Confidential VIN is stamped into a part of the vehicle that makes it nearly impossible to destroy. The rental truck used in Oklahoma was identified by the rear axle that had been blasted from the scene and was located some distance away. The Confidential vin is usually stamped into the frame, often inside a section of tube accessible only with a mirror and is often reversed so to the eye, it looks like gibberish. A C-Vin to an older model Corvette is on top of the drivers frame rail under the door. To see it, you must cut away the fiberglass threshold or take the body off the frame to see it. However, if the car has burned, the aluminum vin plate will have turned to slag so this number will still be available.


There’s also a VIN sprayed on the underbody and only visible with an ultraviolet light

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    Welcome to Motor Vehicle Maintenance & Repair! Do you have any references to support this? How would an ultraviolet paint remain viable, especially on the underbody? You can't even get rust inhibitors to stay on the underbody. May 22, 2022 at 12:25
  • As per Paulster's comment - this just is not true on any car I have had. I know because we have used UV light for various diagnostics and displays on these vehicles.
    – Rory Alsop
    May 22, 2022 at 23:23

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