Milage in ECU or gauge cluster?

[Spooled]

I need to replace my instrument cluster myself (dealers charge WAY too much, so I am salvaging one), but I don't want to commit a federal crime doing it by having the wrong milage on the new odometer. Is the milage stored in the ECU or in the cluster itself? I have a friend that should be able to update the cluster if it's stored there, but I want to know what to expect. Also, is there any VIN or serial information stored in the cluster that will look weird to a tech?

[PaulMP3]

i would assume it is stored in the cluster, b/c people who swap mp3 ecu's mileage isnt effected.

[Captain KRM P5]

i believe it is stored in the cluster. as long as you disclose there is a mileage discrepancy to whomever buys the car from you, i did not think there was a problem.

[Spooled]

OK, thanks. I will probably just have a tech match the milage to my current cluster.

[Turbo Matty P]

I'm not sure how it's stored. I think the actual mileage is stored on the ECU, and the trip is stored in the gauge. When I disconnected my gauge cluster I lost my trip count, but not my mileage. Any ideas?

[t3ase]

Milage is kept in the guage cluster itself. The ECU does not keep track of milage. I *believe* the cluster utilizes EEPROM memory which allows storage of data without erasing it on power loss, along with the ECU.

[Installshield 2]

There is probably some kind of battery in the cluster for the odometer that only powers the total mileage, which is the more important part...or types of memory that is not lost during power failures...

Like Paul said, nobody commented on different odometer readings when swapping ECU's...

the simplest way is to get a notorized document when you do the swap...You can get a document to keep with the owner's manual that states the mileage before the cluster swap...that is what everybody did back in the 80's when the U.S. employed a shit system of having every foreign car's speedometer only display up to 75mph...Almost every Porsche owner went and swapped out for a european cluster that had higher numbers and looked cooler...it is completely legal as long as you have the document officially notorized, and have it during the sale of the vehicle...and it costs like 6 bucks to get the paper work completed...

[mp5jeff]

its stored in the gauge cluster most likely, my friend who will remain anon, switched his gauge cluster and it reads the mileage from the old car

[Spooled]

Originally posted by Installshield 2
...the simplest way is to get a notorized document when you do the swap...
...it is completely legal as long as you have the document officially notorized, and have it during the sale of the vehicle...and it costs like 6 bucks to get the paper work completed...

Where would I get something like this? Will the dealership be able to do this? Who do I have to go to to make it official. Thanks for the great info by the way!

[BlkZoomZoom]

Spooled- why do you need an instrument cluster......and what did you do so its not under warrenty?

[ELEmental59437]

Originally posted by Turbo Matty P
I'm not sure how it's stored. I think the actual mileage is stored on the ECU, and the trip is stored in the gauge. When I disconnected my gauge cluster I lost my trip count, but not my mileage. Any ideas?

If your not sure, then why post? Your just giving out false information. Two people already answered the question with the correct answer. The mileage is stored in the gauges, NOT the ECU....

[t3ase]

...via EEPROM memory.

[t3ase]

HEHE!

[Installshield 2]

Originally posted by Spooled
Where would I get something like this? Will the dealership be able to do this? Who do I have to go to to make it official. Thanks for the great info by the way!

Not exactly sure on "how" you go about it...Contact a notary service center...Which is where you go if you do a private car selling, they are needed for the title transfer...Notary service guys are pretty common...I didn't think any were in my area and it turned out that more than 5 were...just check your phone book for notary related stuff, or try a post office (they use them for notarized letters)...And yes like you mentioned, the dealership will probably have some sort of contact with a local notary service...

You will most likely need someone from the notary place to go with you to swap the cluster...They first verify your current mileage, then verify the new mileage...and plug in the adjusted difference for the paperwork...You could theoretically do the swap in the places parking lot...in which case you only need the dude to walk out and look at your odometer before and after the work...Just explain to them what you are doing and they can let you know how to go about it better than I can...

[Pheonix]

now if this is simply eeprom, then why can't it be electronically erased??

is anyone aside fom mazda manufacturers authorized to do this?

[Dexter]

Originally posted by Pheonix
now if this is simply eeprom, then why can't it be electronically erased??

is anyone aside fom mazda manufacturers authorized to do this?

find the chip, first of all.

it is possible it is EEPROM located as part of a microprocessor.
So you'd have to find both all the MCUs and EEPROM chips on the board, examine each one. Desolder, rip apart, hack away at the expensive gauge cluster. EEPROM reader/writers aren't exactly cheap either. *shrugs*
i mean , anything is possible, with the right resources and time, but....

[Pheonix]

sucks, i have this gauge cluster, 2k1 i think, same as mine but with tach. only fuel/temp gauge unscrews. the other two need to be de-soldered.

i thought the mileage was held on a chip attached to the speedo but it's mounted right to the board, just one chip to rule them all.
i would use it but it has 23k+ more miles than my car.

maybe, thought, the eeprom is entirely seperate and is hidden behind the speedo. perhaps i'll be fully gutting this cluster after all.:confused:

[Dexter]

it would be very interesting to figure this out though. i just dont want to sacrifice my cluster for experimenting.

[Pheonix]

wow, just found out that every one of these units are swappable.
very easily.

the solderpoints are polls which go into each gauge and there are two clips in which you press and then the gauge will pop right off.

my webspace is down, any free places to upload pics that won't be deleted the next day.

[Dexter]

pics, sure

[Pheonix]

it has leds for the dummy lights, but i guess that main chip is for storage as well, it leads right to the lcd.

that damn LCD is held on so loosley, i almost broke it.
it's held by a plastic case, green in this case for theme.
try to remove the case and the lcd may come with it.

on my stock cluster, i have blue leds in the back, it seems to shine through the green well.

[Pheonix]

thanks yahoo. hopefully the links stay.

http://us.f1.yahoofs.com/users/3fa753ec_aea3/bc/My+Photos/__sr_/pic7.jpg?bcIh1p_AXLxUMsFm

http://us.f1.yahoofs.com/users/3fa753ec_aea3/bc/My+Photos/__sr_/pic6.jpg?bcIh1p_Aj5vhNse0

http://us.f1.yahoofs.com/users/3fa753ec_aea3/bc/My+Photos/__sr_/pic5.jpg?bcIh1p_A.HmsxJPM

[Dexter]

that big IC in picture number two is probably just the LCD driver chip....any numbers on the chips?

[Pheonix]

99 50 H
74HC14A

big boy
YNS inc
ICNE 10M9904B

TA 949
8008F

MC14013B


edit: some weren't correct

[Pheonix]

it's crazy how much room there is, you could run a whole shlew of leds throughout it.

[Dexter]

the MC14013B is a flip-flop logic chip.
74HC14A is a hex inverter chip.

no clue what the hell the other ones are. damn.

[Pheonix]

did you see the website for the big chip?
they make the whole cluster, and show the chip right on the main page and show mazda interior shots!
all japanese though

[Dexter]

yeah, i see that now.

and because of that, i say that it is practically impossible to reset or change the mileage yourself

[Pheonix]

yeah, who knows, maybe if you could get it to count really fast and roll over. they might not have even designed it to be electronically set.

you'd think mazda could set them for a replacement.

[TheMAN]

the links aren't working for me, can someone just attach the pics here?

[Pheonix]

sorry, i cannot remember what aol set my password to.

here is the yahoo photo thing.
Yahoo Photo (http://photos.yahoo.com/daonepheonix)

[Dexter]

Originally posted by Pheonix
yeah, who knows, maybe if you could get it to count really fast and roll over. they might not have even designed it to be electronically set.

you'd think mazda could set them for a replacement.

thats probably the only way to do it. if it even does roll over. but actually connecting up to the chip itself, is highly impossible without a datasheet or some kind of communication standard.

to try that you would have to...figure out what sends the pulse to the chip, basically, the clock line. then continually pulse it until it maxes out, and maybe it will roll over. but im not too sure of that either.

[TheMAN]

damn... that shit looks complicated in design.... so why bother with chip swapping when swapping the whole damn circuit board is easier? from what I can tell, the connections from the gauges to the circuit board are larger than the chip itself, so this means it is easier to work with

[TheMAN]

according to my mazda documents on the BJ protege gauge cluster, the input signal feed to the speedometer is 8 pulses/one rotation of speedometer driven gear and the output signal from the speedometer is 4 pulses/one rotation of speedometer gear... it also says it runs on 12 volts... of course I would try 5 volts first so that we won't fry anything ;)

I have no idea WTF the "input" and "output" speedometer signal is for... I'm too lazy to look in the wiring diagrams right now to see why


Originally posted by Dexter
thats probably the only way to do it. if it even does roll over. but actually connecting up to the chip itself, is highly impossible without a datasheet or some kind of communication standard.

to try that you would have to...figure out what sends the pulse to the chip, basically, the clock line. then continually pulse it until it maxes out, and maybe it will roll over. but im not too sure of that either.

[Pheonix]

i'm going to make an attempt to "safely" dissasemble my DX cluster and see if the wiring is there for the tach, and maybe i could get a clean signal.

[Dexter]

you cant "chip swap" a surface mount soldered IC.

who knows the comm. specs of the chip and im sure YNS wouldn't just give it out.

anyways, the point isn't to trade chips, or swap circuit boards. what would be the point of that? you can just swap the entire cluster with the same results, ie incorrect mileage. the point was to figure out if the EEPROM chip that stores the information is easily accessable, and if yes, is there a way to read/write information to it. seing as how YNS seems to have a propreitary design going on here (not utilizing Microchip PIC, motorola MCU, etc), its practically impossible to "extract" the chip from the board, throw it into an MCU programmer or EEPROM writer and fuck with it.
unless YNS is using one of the major MCUs and just stamping thier own name on it, but by looking at thier website, they control the entire creation of the gauge cluster, so im saying its safe to assume thier design is propreitary.

[Pheonix]

Originally posted by TheMAN
according to my mazda documents on the BJ protege gauge cluster, the input signal feed to the speedometer is 8 pulses/one rotation of speedometer driven gear and the output signal from the speedometer is 4 pulses/one rotation of speedometer gear... it also says it runs on 12 volts... of course I would try 5 volts first so that we won't fry anything ;)

I have no idea WTF the "input" and "output" speedometer signal is for... I'm too lazy to look in the wiring diagrams right now to see why

it'd be crazy to see this thing run with a function generator or 555 timer.

[Dexter]

LOL pheonix. i was just imagining that scenario.

[TheMAN]

(werd) I KNOW that the odometer is on the EEPROM, *but* how it is stored on their is a mystery


Originally posted by Dexter
you cant "chip swap" a surface mount soldered IC.

who knows the comm. specs of the chip and im sure YNS wouldn't just give it out.

anyways, the point isn't to trade chips, or swap circuit boards. what would be the point of that? you can just swap the entire cluster with the same results, ie incorrect mileage. the point was to figure out if the EEPROM chip that stores the information is easily accessable, and if yes, is there a way to read/write information to it. seing as how YNS seems to have a propreitary design going on here (not utilizing Microchip PIC, motorola MCU, etc), its practically impossible to "extract" the chip from the board, throw it into an MCU programmer or EEPROM writer and fuck with it.
unless YNS is using one of the major MCUs and just stamping thier own name on it, but by looking at thier website, they control the entire creation of the gauge cluster, so im saying its safe to assume thier design is propreitary.

[TheMAN]

I think the first step is to dump the EEPROM and then try to reverse engineer it... maybe it uses some form of recognizable ASM code?

[Dexter]

TheMAN,
what wiring diagrams are you looking at?

in the case of not having any diagrams at hand...
we know the input signal has to come INTO the gauge cluster. so one of the wires must ... pulse... damn its late why am i thinking about this...anyways...

are there any unused pins in the harnesses? maybe those might hold an answer.

also, what if you just pulsed the fuck out of the speedometer wire?

[Dexter]

Originally posted by TheMAN
I think the first step is to dump the EEPROM and then try to reverse engineer it... maybe it uses some form of recognizable ASM code?

my point is that how can we even dump the EEPROM from the chip? just being surface mount makes working with it hard enough. :'(

[TheMAN]

I know that the PS2 modchip guys use a razor blade to solder wires to the SMT ROM BIOS chip, so maybe we can just use the same trick ;)

[Pheonix]

i'm curious of the wiring diagram also.

surely it doesn't use all those wires, well maybe with cruise and such. perhaps there is a link to talk to the ECU, nahh... but why not.

i'll go house on this as far as pulsing goes and even hook it up to my webcam or just do the 15s of video my camera does.

have a nice new, was going to be used with an RGB led but too many projects already, 555 still in crappy radio shack pack.

[Dexter]

Originally posted by TheMAN
I know that the PS2 modchip guys use a razor blade to solder wires to the SMT ROM BIOS chip, so maybe we can just use the same trick ;)

Cool, now all we need is a pinout of the chip! :p

[TheMAN]

anyone have tylenol? :o

[Pheonix]

Originally posted by TheMAN
anyone have tylenol? :o

thanks

no tylenol, but i have a big mallet, works pretty well.

that diagram is so much more complex than the fog light one i had the mazda tech get me.:eek:

[BrianV]

My uncle bought a Benz S600 from Canada, it has kilometers on it and he wanted mph. He bought a new MPH US guage from a Benz dealer online, cost him a fortune, and he had his local benz dealer install the guage. He had them convert the km to mi. He has documentation of how many miles were on the car, the date of the swap, and that the swap was done at a dealer. The dealer put on the invoice that milage was matched.