How does the Odometer store its memory?

[REdOX]

What's the source of storage for the odometer? Is it a battery backup like a watch battery that keeps a charge on some IC's? And how long will it last?

[CloNeGTS]

I'd guess it's something that doesn't require power....kinda like a hard drive. I'm no electrical engineer, so I dunno.

[GTS LAID]

EEPROM in the gauge cluster

[b0x]

Just a thought... If you drive without your guage cluster connected, does it still gain millage? *wink wink* :)

[CloNeGTS]

I don't think the car will work with the gauges unhooked. Too many things are wired thru it. For some reason the DRL wire that you cut in my install runs to the gauges. It's almost like a second mini ECU

[REdOX]

eeprom hmm.. wow. Yeah, you wouldn't need a HDD to store a 6 digit number.

[adminmike]

Have anyone figured out where the mileage is stored and the calculation algorithm?

Here is my eeprom dump:


Device: 9346
Note :
Size : 128 Bytes CRC: 7E53
000000) FF 80 FF 80 FF 80 FF 80 - B6 7F FF DF B6 7F FF DF ÿ.ÿ.ÿ.ÿ.¶.ÿ߶.ÿß?
000010) B6 7F FF DF FF FF FF FF - FF FF FF FF 8E 03 8E 03 ¶.ÿßÿÿÿÿÿÿÿÿŽ.Ž.?
000020) 8E 03 85 11 BF A6 FF DF - 85 11 BF A6 FF DF 85 11 Ž.….¿¦ÿß….¿¦ÿß….?
000030) BF A6 FF DF 77 15 CB BD - FF DF 77 15 CB BD FF DF ¿¦ÿßw.˽ÿßw.˽ÿß?
000040) 77 15 CB BD FF DF FF 8F - FB FB FF FB FB FE FB FE w.˽ÿßÿ.ûûÿûûþûþ?
000050) FB FE FF 27 FF 27 FF 27 - B4 B4 00 B4 FB FB FF FB ûþÿ'ÿ'ÿ'´´.´ûûÿû?
000060) FF 5B FF 5B FF 5B AF AF - FF AF FF FF FF FF FF FF ÿ[ÿ[ÿ[¯¯ÿ¯ÿÿÿÿÿÿ?
000070) FF FF FF FF FF FF FF FF - FF FF FF FF 10 10 FF 10 ÿÿÿÿÿÿÿÿÿÿÿÿ..ÿ.?

[CRBCelica]

10 year old thread

[three79rx7s]

interesting byte dump

the FF 80 FF 80 FF 80 FF 80 is probably a beginning of file marker and power on memory test to initiate ecu has access to eeprom.

the 10 10 FF 10 is probably an end of file marker.

the FF in between all of the other bytes is a delimiter

There are only 128 Bytes, That is nothing to sort through.

best to do a run and sample to spot the location for mileage,
be careful not to damage the EEPROM ( mechanical and static discharge)or you may be sunk

use this dump as initial sample. drive exactly 1 mile or something of its fraction you think makes sense.
sample the EEPROM again, see if you find a change in a byte that reflects the increment you have driven.

post back here for review

You may have to do this for each digit on odometer to figure out where that byte is in the EEPROM as they may not be in sequence next to each other. The hint for this is that the bytes themselves are probably encoded to their meaning for the mileage. ie for a hypothetical example: the byte 1F has a value of DF (remember this is a Hex number) this value is 223 in base 10. So if they are doing this they should do the aformentioned too for security. I would bet there is an algorithim in the ECU that will modify this number for a mileage digit, part of a digit ect. Remember this is a hypothetical example and this byte location 1F may not be for mileage.

In any case it would be interesting to see the byte dump samples with mileage increments.

I should note toyota said I had a bad gauge cluster a while back and they replaced it with a new one and sent it away for the mileage to be encoded in the new unit. Somehow I am not sure I needed a new gauge cluster, but to continue, They are not even letting dealers do this. Thank goodness because all of the sudden if there is no history on the car the mileage changes from 150K to 50K on the used car lot ( I will use the term dealers to mean anybody really). To keep dealers copying EEPROMS anyway and swapping into another car, the vin and other info has to be on this chip too for a match. If not, my design would be send info to the ECU > Dont start the car. And I would design it worse, there would be another EEPROM or wrose an EPROM or worse a PROM in the ecu that gets flagged with a tamper code and the car wont start ever (unless all the parts are swapped out). If you were not smart enough to look at all circuits before hand and if a tamper code is used how would you know what happened. It gets pretty busy. Kind of like mental quick sand.

The end point is I would not expect to find a simple sequential mileage encodeing, I would expect security measures along the way in your exploration.

Besides I am looking for a good C60 tranny with lower miles one busted or not. I would not want one represented with 100K less miles on it. Same if I was buying a used car.

[adminmike]

wow, that is very open answer. I will put mu cluster on the frequency generator to simulate mileage. the only problem is I cannot seem to read it while its connected to the board, so I have to use "twizers" desolder it. I also want to know how to make it work for automatic transmission


FBI is on its way
:hide:

[three79rx7s]

Thats how the design should be open ended, non concrete, for discouraging prying eyes

buy a socket to solder onto the board then plug your eeprom into that. if you keep desoldering you will ruin the chip. when you start soldering/desoldering on the board it will be obvious you have altered the board. If you plan on just swapping boards later to hide this., I could not imagine just being able to do this. There are probably check digits on the gauge cluster and EEPROM that have to match to foil EEPROM swaps board to board.

If you use a signal generator do you know how many pulses you need to relate it to the speed sensor signal generated per unit mileage. When you roll up the miles on the EEPROM do you want your car now to show more miles than you have driven.

What is the mechanism on the automatic, the same speed sensor? is there a different ecu for manual vs auto? same ecu and different electrical connectors for manual vs automatic? or same ecu and same connector

as far as the ecu and eeprom are concerned a signal is a signal to increment the mileage.

[adminmike]

already soldered a socket ;)
Automatic got shifting lever position section lit up. Manual does not.
There is no pair between the micro and eeprom (I think). I've backed up my original state and was able to return to it, So that should be pretty easy to roll back.
Speed frequency is still a frequency. Just ramp it up slowly ;) Got several readings pm me your email I will send them to you if you like puzzles

[three79rx7s]

If your a major auto co. like ford or toyota or GM ect. that needs help improving circuits or adding security to their circuits, ecu's, eeproms/eproms, sensors and the like; sounds like a great project. I would be up for the task to explore for innovative solutions. Sounds like a great opportunity and I would like to talk business with you.

If you are a racing outfit that needs to sample engine/and operating parameters real time on the quest of better performance and needs mileage as one of the parameters to follow, Again, I would be up for the task to explore innovative solutions. Sounds like a great opportunity and I would like to talk business with you. As we move more in this direction, I am sure there are federal regulations that must be followed when accessing and changing things like odometer readings, I would expect to find that permits and licenses are needed. The government loves to collect fees for licenses , just like McDonalds loves to sell alot of fries.

But if your asking me to help an individual without protective contracts decode odometer circuit firmware or software algorithms that can be ported to production cars with vin ID's that are regulated by the government; the puzzle isnt solving the code anymore. Just like the forum on driving on NC has a section on speeding and the person posts what do i do now, I have a ticket for going 106mph in a 55 zone. Every one answers back .....Your Stupid ....and there is no answer for what do I do now. I dont wish to put myself in this category. I think we are orbiting around this planet currently.

[adminmike]

Unfortunately I am not FORD nor GM, I am just a guy who dreamed about been able to do hi-tech adjustments to the cars. I am not a racer nor "puerto rican space ship" pilot. The car is 99% stock (It has fingerprint start that we developed and real time tracking system) Now I am old enough and have enough money and tools to take on this challenge. How does it feel to do something that not even a dealership can achieve?

Forgot to note - You have a great idea for tamper proof ODO storage, but that would require for your cluster to work 100% of the time. you would disable the car if the cluster stops responding? Like shutting the engine on the railroad crossing? Or you can store the ODO in the ECU (like all modern cars) and have access to it via CAN. There is a lot design improvements that could be done. Don't forget that that was 1998 and a first attempt by Toyota to store digital mileage.

[adminmike]

I was able to figure it out. :wiggle: I cannot describe it and post it here unless I will have permission from moderators, but there is no reason why I cannot help individuals who have to recover their clusters.

http://i66.photobucket.com/albums/h277/mishaf/photo-1.jpg

[narly charley]

I was able to figure it out. :wiggle: I cannot describe it and post it here unless I will have permission from moderators, but there is no reason why I cannot help individuals who have to recover their clusters.

http://i66.photobucket.com/albums/h277/mishaf/photo-1.jpg

Very nice... :gap:

[Smaay]

so are you able to change the mileage to anything you want?

[narly charley]

so are you able to change the mileage to anything you want?

Not like it would matter... It's whatever the title says.

[GSBoek]

I was able to figure it out. :wiggle: I cannot describe it and post it here unless I will have permission from moderators, but there is no reason why I cannot help individuals who have to recover their clusters.
Send the description by PM and I'll have a look at it and we'll decide if it can be openly posted on here or not.

[sc2jz]

I have a certain car that has a mod that does not let it count miles at all it stays the same all the time if u want it to or you can clock miles ... this is a "off road" car and does not have a title or tag just to keep things legal ....

[sc2jz]

Also keep in mind its a federal offence to tamper with that ... also like removing a air bag is a felony so if u get a cop that wanted to push the issue they could.

[GSBoek]

Also keep in mind its a federal offence to tamper with that .

Pretty much why we can't just allow information about it out at will.

[yodaddyguido]

I don't think the car will work with the gauges unhooked

random pointer here. the car works fine w/o the cluster installed. lol it just doesnt cruise, radiator fan doesnt kick on, and you get all sorts of cel codes when you plug it back in regarding your speed sensor and misfires. oh and lift doesnt work either. oh and AC.

[NoRulzAt140 Mph]

random pointer here. the car works fine w/o the cluster installed. lol it just doesnt cruise, radiator fan doesnt kick on, and you get all sorts of cel codes when you plug it back in regarding your speed sensor and misfires. oh and lift doesnt work either. oh and AC.

That sounds like it is working fine.

[Rocky_]

Cars are not wirelessly synced to anything. Atleast not ours, the brand new cars are rather more networked I guess... but our cars are not, which means our cars can be tricked.. I was studying electrical engineering but I stopped. So take what I say with a large dumping of salt. Anyway, there's nothing magical to a sensor. It is built to send certain signals to something that then potentially translates it into hex, binary, ect.. All you have to do is monitor what type of signal that is with an oscilloscope, and replicate it with a frequency generator at a faster cycle. I'm sure it is still rather difficult in where to find this signal, what sensor or sensors. And then there is whether or not the gauge ticks over to 0 miles after 999,999 or simply gets stuck at it. It's not a mechanical odometer after all.

Remember, I could be totally off! adminmike most certainly may laugh at how wrong I am, just thought I'd add my 2 cents

[Muirner]

Not like it would matter... It's whatever the title says.

it'd be nice to have this ability though. Just think, you could switch to a JDM cluster and actually have the proper KM on the guage.

[xxgaxx13]

i would like to know how to change the mileage on the ODO. i just got 03 gauges and wanted to do the 00-02 to 03+ gauge conversion but would like to match the mileage

[Rocky_]

You could try opening the gauge clusters and swapping out the circuit boards. Idk if they are any different from year to year, I doubt it. Probably your best bet, it may not be very likely that we can do this unless adminmike is allowed to post how or someone else goes through with an oscilloscope and finds the wire to tap into and then get a frequency generator...

Best bet just transferring the PCB. If you look up a guide to change the color of the LED's on it you may be able to do it no problem.

[xxgaxx13]

so did they figure out if they can post how to to change the mileage?

[yodaddyguido]

That sounds like it is working fine.

well, if he just needs to drive it somewhere, it'll be fine.