Sunroof Control Unit Long Coding

[deepy]

I have been comparing VCDS scans of my 2018 RS3 from when I got the car and from a few days ago and noticed that the Long Coding on the Sunroof control unit J245 has changed from '901F00' to '901E00' !!
The pan roof was changed earlier this year so was probably recoded hence the change, but has it been done correctly. The operation of the roof seems to be working ok but why the change to Byte 1 ?. I appreciate that by ticking the box on Bit 0 will put the Hex coding back to 1F. As there aren't any label descriptors does anyone know what Bit 0 is or any of the bits for that matter ? thanks
Perhaps @DJAlix or @T-1000 can help.

 

[8YARWY]

I have been comparing VCDS scans of my 2018 RS3 from when I got the car and from a few days ago and noticed that the Long Coding on the Sunroof control unit J245 has changed from '901F00' to '901E00' !!
The pan roof was changed earlier this year so was probably recoded hence the change, but has it been done correctly. The operation of the roof seems to be working ok but why the change to Byte 1 ?. I appreciate that by ticking the box on Bit 0 will put the Hex coding back to 1F. As there aren't any label descriptors does anyone know what Bit 0 is or any of the bits for that matter ? thanks
Perhaps @DJAlix or @T-1000 can help.

Hmmm I wonder if it’s just a newer firmware because of the new pan roof ?

Doesn’t help because there’s no labelling in that module.

Does it allow you to change back to the original long coding ?


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[NHN]

Tbh best is to compare module versions & firmwares, if it's different then would possibly explain, if no feature change.

Using Odis & comparison with vcds may elude to what the non documented change relates too.

 

[DJAlix]

I have been comparing VCDS scans of my 2018 RS3 from when I got the car and from a few days ago and noticed that the Long Coding on the Sunroof control unit J245 has changed from '901F00' to '901E00' !!
The pan roof was changed earlier this year so was probably recoded hence the change, but has it been done correctly. The operation of the roof seems to be working ok but why the change to Byte 1 ?. I appreciate that by ticking the box on Bit 0 will put the Hex coding back to 1F. As there aren't any label descriptors does anyone know what Bit 0 is or any of the bits for that matter ? thanks
Perhaps @DJAlix or @T-1000 can help.

If it ain’t broke then don’t fix it. My guess is the coding is what’s needed for a redesigned part in the roof, no labels exist that I can see.

 

[NHN]

Labels don't exist in vcds unless connected to the car with vcds, encrypted no less, unless previous screenshots have been taken or alternative diagnostic systems denote the byte, bit etc differences.

The way to look at is to use Odis or vas(albeit old & tbh hardly used now) Check options & see options are available & changed within vcds, then see what's different, unfortunately it's a very laboureious job for very little knowledge or gain, in this instance it would be advisable to just not bother unless there's something of specific interest or difference to track down.

 

[DJAlix]

Labels don't exist in vcds unless connected to the car with vcds, encrypted no less, unless previous screenshots have been taken or alternative diagnostic systems denote the byte, bit etc differences.

The way to look at is to use Odis or vas(albeit old & tbh hardly used now) Check options & see options are available & changed within vcds, then see what's different, unfortunately it's a very laboureious job for very little knowledge or gain, in this instance it would be advisable to just not bother unless there's something of specific interest or difference to track down.

There are no labels for the module and in question. Ross-tech have not mapped it and ODIS does not detail any. VAS was phased out years ago so will not be of any use.

 

[NHN]

In terms of vas, as I clearly denoted, it's old & hardly used, except for some non vag shops, it's not as phased out as you would believe.

Vas isn't of no use at all, it's a useful tool still, in use by dealers at times as odis hasn't been as reliable as required, I know of a top Audi dealershop who still uses this, odis & vcds given they all have there merits against eachother & cost basis of each vcds is X, existing vas is y & odis is z.

If you change an option within odis & compare the coding etc within vcds, you can at times see where this change has been made & actually advise RT of this advisory of which they will, once checked, update the encrypted label file, they may ask for a debug unless it's a request or update already in line for a new release.

It's basics of comparisons between diagnostic tools, what changes are shown after a change in another show an obvious feature undocumented & it's how all these systems work of eachother at times.

RT & others don't document every module feature at times due to safety concerns of showing or allowing features to be changed through concern it may cause damage to a module or vehicle this resulting in a claim against them.

There are countless forum advisories where users have found undocumented features either by accident & people just tick or adjust a bit, byte hex code to suit, been going on for years.

 

[deepy]

Hmmm I wonder if it’s just a newer firmware because of the new pan roof ?

Doesn’t help because there’s no labelling in that module.

Does it allow you to change back to the original long coding ?


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Hi Sean, thanks for your reply,
The hardware and software have the same revision numbers so nothing appears to have changed.
I haven't tried t0 revert back to the original coding as I was intrigued to know first what Byte 1, Bit 0 did. This looks like a forlong task so I may revert back to Long coding 901F00 anyway and see what happens.

Thanks to @DJAlix and @NHN for their replies

 

[DJAlix]

In terms of vas, as I clearly denoted, it's old & hardly used, except for some non vag shops, it's not as phased out as you would believe.

Vas isn't of no use at all, it's a useful tool still, in use by dealers at times as odis hasn't been as reliable as required, I know of a top Audi dealershop who still uses this, odis & vcds given they all have there merits against eachother & cost basis of each vcds is X, existing vas is y & odis is z.

If you change an option within odis & compare the coding etc within vcds, you can at times see where this change has been made & actually advise RT of this advisory of which they will, once checked, update the encrypted label file, they may ask for a debug unless it's a request or update already in line for a new release.

It's basics of comparisons between diagnostic tools, what changes are shown after a change in another show an obvious feature undocumented & it's how all these systems work of eachother at times.

RT & others don't document every module feature at times due to safety concerns of showing or allowing features to be changed through concern it may cause damage to a module or vehicle this resulting in a claim against them.

There are countless forum advisories where users have found undocumented features either by accident & people just tick or adjust a bit, byte hex code to suit, been going on for years.

Not talking about VAS usability, talking about VAS in context to the posters topic / question... it’s an old tool and will not, actually dose not, have any labels for the module “in question”, and nor does the current version ODIS.

 

[8YARWY]

Hi Sean, thanks for your reply,
The hardware and software have the same revision numbers so nothing appears to have changed.
I haven't tried t0 revert back to the original coding as I was intrigued to know first what Byte 1, Bit 0 did. This looks like a forlong task so I may revert back to Long coding 901F00 anyway and see what happens.

Thanks to @DJAlix and @NHN for their replies

As long as it operates as it should then You should be fine.

I’ll plug in and look at my long coding tomorrow.


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