Combination meter, speedometer, cluster. EEPROM memory analysis.

Good night guys,

I want to convert my EURO 2008 Prius car to be able to measure in Miles and KM (MPH & KM/H) because I imported it into UK.

Because of that I purchased an USA dash, that shows the speed in MPH and KM/H pushing the button on the right of the ODO/TRIP one.



If you directly assemble a USA dash into an EURO car, it apparently works. It reads speed in MPH and Km/h pushing the button closer to ODO/TRIP, but you lose some LED indicators surrounding the dash like the EV and headlamps icons. Furthermore the petrol indicator starts flashing and indicating a ~20% less fuel than real value.

Trying to solve this compatibility issues, I desoldered the segmented display from the EURO and the US PCBs and swapped it (they have same pinout).



I get again an fully EURO dash, with no change in speed units if you push the button on the right of the ODO/TRIP button. It always reads in KM, KM/H and L/100KM. Even the MPH segment is now available in the display.

So, I reprogrammed the 93C66 EEPROM in the EURO dash with the an USA dump, and the behaviour then will be the same than if I were assembled the whole USA dash, with the positive difference that I now recovered the EV and headlamps icons around the dash, probably because it need dedicated layout available only in the EURO dash PCB. I can conclude than the both dash PCBs are not 100% same hardware.

I only achieved read the eeprom memory desoldering the segments display and then desoldering the EEPROM chip. I used a cheap USB eeprom reader from ebay called SP200SE with wires to the EEPROM chip.

I am attaching you 2 93C66 EEPROM memory dumps for your information, red bytes are the differences between both files:



I discovered, some interesting functionality changes using an USA EEPROM dump into a EUROPE dash, like fuel economy is shown in MPG instead l/100km, backlight of nav screen not dimmed down when turn on head lamps, petrol gauge measures ~20% less and flashes, etc...

My investigations are into understand what are the meaning of the remaining bytes in EEPROM that are not the ODOmeter value to fix this mentioned before issues.

I guess that some of them should be the Mileage units, region byte, fuel economy unit, petrol tank calibration, or so.

Do you know what are the meaning the other bytes?

Probably comparing lots of EEPROM dumps from different regions...? I need more dumps!! Can anyone help me?

Could you please provide a Toyota prius 2008 UK dump?

Best regards.

 

I found the perfect Bitmap to flash into my EU-USA hybrid cluster for drive into UK!

Features:

- Measure speed in KM/H and MPH pressing the button on the dash.
- ODO Distance in Miles.
- Fuel economy in MPG.
- Display screen dim off function working properly when pressing the button on the dash with the tail lights on.
- EV mode auto off at speed > 50km/h or 30 MPH.

#2 Prius 200x 038396 miles (D308) - [KMPG-MPH][MPG][DIMM-OK][MILES][EVoff@50KMPH-30MPH]

Note that it is impossible to edit the non ODO meter bytes because they are protected with some kind of CRC-16 in bytes 0xCE and 0xCF. If you modify some bytes without recalculating the mentioned 2 bytes, ODO value starts flashing and the SAT NAV indicates fuel economy in KM/L (¿?).



So, at the end I was very lucky to found this EEPROM bitmap!

Regards.