How easy is it to turn back the Odometer?

[Flash Gordon]

Bump

 

[Gerald Levin]

About 20 years ago a friend of mine had what is called a reducer. You would disconnect the speedo cable insert this reducer between the speedo cable and the speedometer and the reducer would reduce your speed by 50% and your mileage by 50%. Hence if you were going 50mph the speedo would register 25mph and the mileage would be reduced by 50%. Would a reducer work in todays cars?

 

[Motor City Mad Man]

Surprising how much open talk there is about swapping PCMs and Speedos. It is a Federal offense if you sell your car without disclosing any mileage tampering. You can do anything you want to the vehicle while you own it. Heck turn the mileage back to zero if you like, but you must tell the buyer.

Discussing this or having the knowledge to do it is one thing, actually doing it is another. This post started with someone concerned a Viper they are looking at may be showing less mileage on the odometer than it actually has. So I think some people on this board wanted to warn others that yes it would not be too difficult to do and explained how it could be done. Personally I would never alter the odometer or misrepresent any vehicle I own due to ethics alone. It wouldn't even matter if it was illegal or not. As for my Viper I am going to own it until I go to my grave, so I could care less what the odometer says anyways.

 

[Jerry Dobson]

Gerald,

In the early days Speedos were mechanical. You would need a gear reducer.

Todays Speedos are electronic. Yes, a reducer would still work. A type of reducer is used as a calibrator box when you change your rear end gear ratio.

Pontiac uses a reducer built into some of their cars. The Vehicle speed sensor sends out 4000 pulses per mile, it goes into the speedo and comes out 2000 pulses per mile. It then sends the 2000 PPM back to the ECU. So if you disconnect the Speedo on these Pontiacs, the car will barely run and generate check engine light.

 

[Jerry Dobson]

Right now there is a discussion on the Ferrari Forum about "Disconnected Speedometers".

I have always felt that many of the Ferraris have more miles than the meter shows.

Basically ...the older Ferraris have very few miles (disconnected Speedo). The newer Ferraris have more miles on them. Why? Because it is very difficult to disconnect the Speedo on newer cars and now the PCM keeps track of the mileage (early Ferraris did not have this feature)

 

[Big Medicine]

Just add a dummy circuit; the wires come in & go out somewhere. Meg 'em & mirror the voltage ranges. If someone really wanted to, there's no way to stop it.