NefMoto

If this is in the wrong section I'm sorry, I was not sure on the best place to put it. I hope its ok here.

First off, This is my first experience of eeproms and flashing so this is all a massive learning curve for me so I apologize if the questions are simple or stupid.

I recently sorted out a oil sensor and some wiring bits on my A4 B5 so I can fit B5.5 clocks.
It's all wired in and working fine at the moment apart from the rev counter.

I was reading a thread on AudiSRS where someone fitted RS4 clocks to his S4 and he had the same issue with his rev counter. He got his the RS4 clocks flashed with the eeprom from his S4 clocks and the rev counter worked but other gauges stopped working. That was last update on the thread.

I'm thinking of doing the same with my clocks, flashing the B5.5 clocks with the eeprom from the B5 clocks.
My concern is that the rev counter will work but I will lose other gauges.
I assume there is a line or two with in the eeprom that tells the clocks where to get the signal for engine speed and this line is different to the B5.5 clocks.
If that's the case, can I take the section from the B5 clocks that tells it where to get the engine speed and overwrite that section on the B5.5 eeprom?

I've been trying to get some eeproms from B5 and B5.5 clocks from people so I can compare but I'm not having much luck.
I can get the eeprom data from a spare set of B5 clocks I have but for some reason my version of Vagtacho wont read my B5.5 clocks.


I hope that makes sense. Any help or advice would great.

Thank you.

I don't have the answers to your questions, but I can tell you that both time i tried cross flashing very different versions, i didn't have good results

S4->RS4 cluster ended up with a cluster that wouldn't display the date correctly

new A6->old allroad cluster ended up *bricking* the allroad cluster which required desoldering the eeprom to fix.

So... make sure you have the right tools on hand (I didn't for the latter fuck up) before you go down this road.

Thanks for the warning. I got vag tacho and access to vag commander.
I hope that's enough at the moment.

The S4 -> RS4 with date not working correctly, do you think that's down to the old eeprom confusing the clocks or visa versa?

That's not bad. So I can remove the eeprom chip and put a new one in or one from a different set of clocks to get it working?
Can I do anything with the bricked chip or just bin?

Do you think there is a 'switch' type code in the eeprom to tell it where to get the revs from?

IF you brick the cluster, the only way to fix it is to desolder, and write an encrypted backup to the eeprom. You can't write the OBD read, it won't work.

So, for a foolproof recovery:

Desolder and read the small SOIC-8 EEprom labeled 93C86 located on the back of the cluster. It's located above the clock setting knob. Then you can always recover the cluster in case something happens.

As for the layout, I've found a few things, but nothing that'll do what you want.

Thanks for that. Hopefully I wont need it.

Is there any way to find if there is a rev switch with in the eeprom?

Nyet, apart from the date issue, what was the rest of the cluster like?
Did all other gauges work correctly?

dunno never got that far. I only powered it up on the bench. It seemed really unhappy.

Hmmmm

Need to look at canbus cables from ECU a bit more and also check out fitting a newer ECU in my car then.

Bugger. :(

Update for everyone.

I gave up with the eeprom idea.
Bit of button bashing and I change channel 62 in cluster to immob II from immob III and it works. :)