How the Digital Odometer Works

November 24, 2004, 11:57:52 PM

This was talked about on the other board (can't find the thread!) regarding how the memory chip in the digi cluster could be reprogrammed with a new odometer reading. But no datasheets on the chip could ever be found.

But here is an interesting read for the patent on the odometer, including a little info on the chip, its a whopping 336 bits big! It can also only be written to only so many times, so the patent describes the extra effort to minimize data writes and ensure data integrity. I have verified that during run, the memory does only get written to every 10 miles or so as the patent describes.

The Odo Patent

Or goto http://www.uspto.gov and search for patent 4803646

Click on IMAGES to see the whole patent.

I wonder what other things on our cars have patents? :)

Re: How the Digital Odometer Works

Reply #1 – November 26, 2004, 02:14:20 AM

mmm, thats explain why my digital odometer resets every 16 Km to the old value (46078.9) and never increases.....