NefMoto

Hi,

does anyone know how could I edit the ecu soft coding (me7.5 - 2000 a4 1.8tq)?

I had an immo off mod done and since then the ECU has been throwing me a failed TCU communication code, EPC stopped working and the clutch pedal switch doesn't register.
My guess is the car is coded as an automatic, looking at the soft coding in VCDS, it's "16581" - which by some chart, should be a north american, FWD, multitronic car.
But my car is an EU, quattro, 5spd...

VCDS won't accept my new coding...

Any info on how to solve this is greatly appreciated,
sorry for my lack of knowledge, I'm still learning :)

Soft coding is stored on the EEPROM. Use boot mode to download the EEPROM .bin file and then you can use tunerpro to edit the soft coding, prior knowledge of the SKC is not needed to change the EEPROM file. Other useful stuff you can do in the EEPROM includes reading the SKC (so you can clone original ECU SKC to another ECU), turn off immobilizer, change the VIN to match car if you have a replacement ECU.   
Be sure to reset the check sums after making any changes to the EEPROM file then you can boot mode flash the updated file back to the ECU. Really helps to have a bench harness (made form old spare ECU harness) to do the boot mode flashing since you need to open the case of the ECU. 

I made my own harness with a power switch.
But there are options ready to use on aliexpress for example.

https://www.aliexpress.com/item/1586346900.html

Never needed SKC to change softcoding...SKC only needed for immo to pair to cluster unless it immo 2 which its not needed as it doesnt use one

Oh God where this world is going?

I thought the SKC was needed because VCDS won't accept the coding, after reading through some forums people were saying a login is needed to perform this...

What do you mean? It's literally posted in the noob questions category...
I tried changing the soft coding with VCDS, but it won't accept it, so I'm trying to learn how to "force" it on.

Everyone starts out somewhere and it's very dissapointing to get replies like this even after avoiding the main forums to not disturb the more technical threads with experienced users.
Where would you suggest me asking this question, if not here?

You can't force ecu to code something that doesen't exist in flash. If it won't accept coding that is it. You can't do anything more.

somebody messed up Eeprom. when doing immo off - maybe wrote some random immodest off Eeprom from other ECU - the best way , revert to original and do immo off as it should be done

Thanks for the reply

I see what you're saying, I've read about this on other forums where I've found out that the software for Auto/Manual is different, which is why the soft coding can't be directly changed.
However, the software on my ECU is the same as it was before the immo off, it's a stage 1 file for a manual.
AFAIK the ECU can refuse to accept the coding out of other reasons as well, like TCU fault codes etc., correct?

If I were to read this eeprom, change the coding value, correct the checksum and write it back, would it not work? The coding should then be the exact same as it was before the immo off, and the flash wouldn't change.

This is probably true, however getting it back to original is something I can't do right now, the guy that did my immo off is in a different country, so I kind of have to deal with this mess myself.

He did write something off another ECU I think, because the ecu VIN in vcds doesn't match with my car anymore... I think it's an A4 B6 VIN...

Couldn't I just read this eeprom and correct this coding, then write it back? I know it's more complicated than that and I'm willing to learn, I just need to know it's possible

Yes you can

just so there's not just useless replies like your first one and this one as well, here is how i solved this a year later and never got around to posting it.
The eeprom was corrupted, my flash contained a manual file (tuned file for that exact car) and only the eeprom was coded as an automatic, so your comment saying it doesn't accept coding of something that doesn't exist in flash is funny, I actually checked the VARDEF with WinOLS and my file was as correct as it could be.

Looking back, maybe the coding wasn't being accepted via VCDS, because of the current EEPROM coding not being stored in the VARTAB of the flash.

I did read the eeprom with VAG Commander and made the necessary changes to the file, including changing the VIN because it was from some B6, but couldn't write it back through OBD and I wasn't so good with electronics back then to write to it directly.

Flashing the ori file or reflashing my tune through obd didn't do anything to the eeprom and it stayed coded as an automatic...
...but when I crossflashed a file from a different ECU (TT180 afaik), the eeprom edited itself to the its coding (of the TT file), which was still wrong for my car, however, flashing my tune back finally edited the eeprom back to the correct coding.

This is apparently the easiest way to get this done in this exact situation I was in, if you don't want to open up your ECU or get into boot mode.

So youve got a corrupted eep, 'some tune for that car' and wonder why its not going usual way?
Hes absolutely right - ecu doesnt accept coding which isnt listed at VARTAB and its pointless to force that, and how the hell this correlates to your case? Or you magically could recode it with non VARTAB value?

Coding wasnt accepted bc of corrupted eep or plugged TCU etc

-unplug TCU
-recode can-gateway to the same or new code matching equipment
-clear DTCs at the ECU /reflash ECU if necessary / recode it to manual

The "some tune for this car" was done by a shop before I had any knowledge about doing anything myself. What I wanted to point out by writing "for that car" is that I have later (when I gained some experience around these things) checked the map with WinOLS and compared it to the stock file which proved it was not some janky crossflash but the original map, edited, how good were the edits is another story, but thats besides the point because VARTAB and similar things stayed untouched.


He was saying it doesn't accept something that "isn't stored in the flash", the VARTAB section off the flash was untouched, the coding I was trying to put on the car WAS STORED IN THE VARTAB (obviously, it's the stock file, I think it was even the VARDEF), but the one already coded (because of a bad copy/paste immo off job at another shop) was not, so you're not understanding the situation either. If anything, the ECU has some sort of pre-check to first validate the current coding with the VARTAB values, before also checking the new one and then writing the new one.


Unplug TCU? What TCU? There is no TCU in a manual b5.

The CAN Gateway section in VCDS always failed to connect for me, I assumed the car does not have this module however it was a facelift car so I'm not sure. Did not dig deeper, was unneeded as well.
But even if the car did have this module, how would the coding change for this module if the immo off job was done by physically desoldering the eeprom from the ECU and writing some b6 immo off bin to it?


Anyways, I don't even have this car anymore and the solution to the problem that I happened to stumble upon is quite fast and non-messy, just wanted to share it if anyone lands here from google... and also maybe prove some arrogant people here wrong, who obviously couldn't stand seeing someone getting into car electronics.