Re: No Visible Evidence...Correct

According to the web site I referenced above, there is no visible sign the odometer has been changed on an E38 when you use their device.
Quotes from site:
"Disassembling the dashboard or the odometer is not necessary. Programming BMW E36, E38, E39 & E31 odometers is done via the diagnostic plug in the engine room."
"Is it possible to prove a manipulation of an odometer electronically?
No. Our products work on low system level. It is not possible to determine whether an odometer has been manipulated."

The dot is right next to the odometer. someone may want to over write the odometer after an engine swap or something of that nature.

where is the tamper dot ? are there legitimate reasons why the milage would have to be overwritten?

I think we are still safe due to the little "tamper dot" that comes on when the actual milage is overwritten. i was reading all the info that this manufacturer listed, and nothing is mentioned about NOT triggering the little dot. I hope this means that the odometer really is tamper proof.

My understanding of how the BMW system works is that the tamper dot LED only comes on
if the VIN number coded into the Instrument cluster is different than the one stored in the back up data module (validation between the 2 units every time car is started.)

So if soneone is able to access your instrument cluster and reset the milage, without affecting the VIN number) then the tamper dot will not be lit.

BUT - the cluster still will detect that the mileage is not correct because it will be less than the milage data that is continually stored in the back up data module. And when it detects that difference it sets an error code.
Since the milage in the back up module "can not be reset to a lower number" then the error code will re-occur every time the car is started (even if the error code was reset it will re-occur).

Only way to overcome that is to replace both the cluster and the back up module, and they both have to be coded properly.

Sooooo - when checking out a car have it checked for error codes related to this.

The only time a milage would have to be overwriten is when a replacement cluster is installed. if it is set to "0", then it will pick up the original milage stored in the back up.
Otherwise it sets an error code (and the tamper dot if the VIN was not set correctly.

Cheers
Jim Cash

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