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I bet the other (32 byte) bins didn't have a 0x0A byte in them?

you bet right, they looked normal and easy to read and see the pattern without extra characters

Just tried the DF 20 swap and it worked LOL.

With all the different numbers I was not sure it was the same chip and code. But can you make the trip count miles instead of kms?

So thinking along the lines of the DTE - the 80 and 60 tank size have different default DTE readings when changuing trip computers between cars. I should have taken more notice of the numbers - but it was around 720kms for the 80 tank and 600kms for the 60 tank setting.

It must get the data from the trip computer some place when powered up and then it changes it as the travels kms. It stores this data until the trip computer is disconnected from power.

Yes the ODO shows Miles - So not just the DTE is changed by the 7/8 byte swap.

It looks like it sets the ODO for the export cars.

i've noticed in the past when swapping ecus in my vn calais, if i'm not quick (as in leave the ecu out for more than a few minutes, i never dc the battery) the dte, avg fuel consumption etc reset, if i'm quick and even with a different ecu it stays the same. the 80c51 must keep some values in ram.

it should all be imperial on the lcd's now with the byte swap, the odo is just the numbers you guys have been changing.
fuel used = gal, dist trav= mls, o/speed = mph, fuel inst = mpg, test mode speed appears to be mph.

road tested in test mode.
speed on the lcd showing 39 mph speedo sitting a needle thickness over 60 km/h (my speedo reads to slow 64ish is really 60)

tried and failed to read/program the chip in circuit, tried with a shielded 2 inch cable from the programmer to chip, the vdo tool must write to the 80c51 to change it.

**removed fail info**

jxx wrote: it should all be imperial on the lcd's now with the byte swap, the odo is just the numbers you guys have been changing.
fuel used = gal, dist trav= mls, o/speed = mph, fuel inst = mpg, test mode speed appears to be mph.

road tested in test mode.
speed on the lcd showing 39 mph speedo sitting a needle thickness over 60 km/h (my speedo reads to slow 64ish is really 60)

tried and failed to read/program the chip in circuit, tried with a shielded 2 inch cable from the programmer to chip, the vdo tool must write to the 80c51 to change it.
so long as there is 8 bytes with a valid odo reading the other 24 can be set to anything, it rewrites the first group along with 2 or 3 copies of the odo bytes, initially it doesn't care what value the other 24 bytes are.

Code: Select all

wrote
00 00 00 00 00 00 00 00 F7 08 EC 13 91 6E 0A F5
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F

pwr on/off
read
01 01 26 D9 00 00 00 00 F7 08 EC 13 91 6E 0A F5
00 01 02 03 04 05 06 07 F7 08 EC 13 91 6E 0A F5

OK will try this some more - when I had anything else in the first 8 bytes other than the 01 01 26 D9 FF 00 DF 20 I would get a fail in the Diag mode.

I got a Fail in diag mode when using your bytes.

Not sure if I got it right so I'll have a more detailed look after work.

ah ok, was late when i did that, didn't try diag mode, posted after i thought it was working

jxx wrote:ah ok, was late when i did that, didn't try diag mode, posted after i thought it was working

I needed to have the first 8 bytes set to default and the next 3 sets of 8 bytes had to be the same or it would fail in Diag mode.

I have a test bench which I can (with 3 buttons) do 12v power - then Ign and the Set button to give the diagnostic mode

just messed about with it some more, so long as the first half is valid it's no probs, it fixes the rest after a few pwr cycles, it also rewrites 1-8 if they're invalid.

now what page was the comparison of all the different models first 4 bytes...

my original dump works but i've noticed it changes bytes 5-8 occasionally, even with the odo reading not changing
vn s2 i think. in regards to the vdo unit previously posted, this adapter works fine on the D8749HD chip, read and programmed fine in the willem programmer
could post it and donate it's use for getting the code so long as i get it back.
not compatible due to pinout for the 80c51, should have something to try read that this week.
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