Digital Odometers


    Digital odometers can't be tampered !

Wrong !  Wrong !  Wrong !
It is so easy to "adjust" a digital odometer it is a joke!

Over the last eight years increasing numbers of new cars have been fitted with digital odometers in place of the traditional mechanical instrument.  Instead of rotating dials, the mileage is read off a screen installed in the speedometer panel.  Initially purely a feature of luxury or top of the range cars, the digital odometer is now standard equipment for some 80% of all new cars. 

Most new vehicles are now fitted with digital odometers.

All you need is a computer, system interface and software and away you go. The software and system interface  is not expense and the hacker would easily recover the costs in the first couple of vehicles.  This and a little knowledge about the vehicles electronic systems and off come the  km's. It is easy to wind of a few km's  or  10,000 km's or if you like a 100,000 km's.  What ever mileage you what, the job is done in less than 5 minutes. 

Why do the car manufacturers make it so easy to alter the odometer reading?

Cost and servicing issues are the main factors here.  The car manufacturers increasing wish to diagnose and correct faults or tune the vehicle through the diagnostic ports.  The digital dashboards can indicate the wrong temperature, fuel, odometer or speedometer readings.  Jump-starting or disconnecting of the battery can cause disturbance of the vehicle electrical system and corrupt settings stored on the eprom memory chips.  The eprom memory chip is the device that records all the vehicle settings.    

It is also very convenient to remove the delivery mileage.

What difference does it make ?

Most of the indicators and physical signs of tampering that are listed in our lemon guide or that are carried out during a traditional professional inspection will not reveal whether the device has been tampered with as the manipulation is achieved electronically rather than mechanically with force.

In a digital odometer, the mileage is usually stored on a chip in the cars central computer.  The odometer reading is now available to be "hacked" by skilled computer operators.  In much the same way that hackers can illegally gain access to protected information over the internet, they can communicate with the supposedly protected chip and reprogram it to display incorrect information.  The successful hacker can simply type in the "new" mileage that will be displayed on the odometer which will then continue to work normally after the tampering.

How do they do it?

To be able to communicate with a digital odometer the hacker must have some physical electronic link to the memory chip.  The reprogramming itself is at such a basic level that it is unlikely to be detectable, but the physical signs of entry can still indicate that the reading is suspect.

There are three basic techniques currently used to gain access to the chip.

  1. Direct Method (D).  A cable must be connected directly to the chip.  This requires the dashboard to betaken apart, the odometer to be disassembled and the chip unsoldered and then reattached to its mount after reprogramming.  
  2. Serial Method (S).  The dashboard is taken apart and a serial cable attached to the rear of the odometer unit.  Here again the dashboard must be disassembled to gain access to the serial port.
  3. Diagnostic Method (DP).  Modern cars are increasingly being fitted with a plug that allows a mechanic's computer to communicate with the car and ask the central computer to diagnose what is wrong with the car or engine.  In some cars, but not all, this plug can also be used to reprogram the odometer.

Methods 1 and 2 are fully detectable.  Some car manufacturers have built in systems for leaving tail tail signs of odometer mileage alteration.  Otherwise if the manufacturer has not put in such systems, alterating the mileage through the diagnostic port (Method 3)  is virtually undetectable.

What can I do about my digital odometer ?

There are a number of signs that a digital odometer has been tampered which can be clearly visible.  Some manufacturers design their digital odometers so that clumsy tampering results in display irregularities.  These irregularities usually consist of unusual characters such as asterisks or a line of 9's across the screen or parts of the display that are missing.  Any of these signs should make you extremely cautious about the reliability of the odometer reading.

If you are suspicious for any of the reasons listed in the lemon guide, such as a lack of paperwork, excessive wear or no guarantee of mileage from the dealer, you should make sure that you investigate the actual condition of the vehicle thoroughly.  Ensure through professional mechanical inspection of the vehicle that you are buying based on the quality and condition, using the odometer reading purely as a guide to give only an indication of mileage.

How common is digital tampering?

From work we undertake in Japan, the failure rate for digitals odometers is rising.  The technology needed to manipulate odometers electronically is able to be purchased easily and relatively cheaply.  The Japanese are a wizz at anything electronic, especially if it needs re-programming. The devices themselves are not illegal and are sold as recalibration units for digital dashboards.  A range of products are available utilising anything from laptop computers with serial links through to portable handheld units.  Software for these devices is being constantly updated as the codes are cracked by hackers.

A good example is the Jaguar XK8.  It is installed with a digital odometer and a computer system designed to foil this form of tampering.  Each time the engine is switched off the odometer reading is stored randomly in one of eight computers distributed around the vehicle.  The theory was that hackers would have to check each of eight computers to discover where the data was being stored.  No problem for the hackers.  They interrogate the central computer and ask it where it stored the reading, ask it to retrieve it, change it and store it back in the same place.  No problem.

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