Strange Coding in MSG

Hello everyone,

I've been looking at some older and newer logging files today. By chance, I noticed that the encoding of the MSG has changed, seemingly overnight. And also on two vehicles!!!
Is my diagnostic interface malfunctioning, or what's going on?
What does this mean? How is this possible?

Here are the engine control unit (ECU) data:

Audi A3, AGR
previous: 038 906 018 A 00SG1001
now: 038 906 018 A 40SG1001


Golf 4, ALH
previous: 038 906 018 AN 00SG1819
now: 038 906 018 AN 40SG1819

I have another question regarding the meaning: What does the numerical value before the gear type (SG or AG) represent?

However, I am not aware of any specific issues, as I have not made any modifications or re-coding.
Who can explain what happened and what the impact is?

Greetings
Alex

donalexo wrote:

Interestingly, I happened to notice that the encoding of the MSG had somehow changed, seemingly by magic. And also on two vehicles!!! Is my diagnostic interface malfunctioning, or what's going on? What does this mean? How is this possible?

Hi Alex,

"The only thing that comes to mind initially is the topic of "Einfahrprogramm"."
Between which mileage ranges did the codes change?

Or could it be related to a switch between WIV <-> fixed intervals?

Hmm...

The 018 models are also 'just' MSA15 (like the late 021 models). They simply have a different housing.
and a different plug.

The designated area is actually for internal (Error?) messages for tax equipment. I got it.
So far, I have only managed to do this once, as I needed a number that was not '00'.
Desoldering the EEPROM (the small SO8 on the bottom) results in '71' and the error message.
'Engine control unit malfunction'

I find it quite surprising that this 'shift' is happening with both vehicles at the same time.
is. Likely indicates an error.

Have you tried a different adapter or a different software version of VAG-COM?

Hi Rudi

'In some way, these little things develop their own personality, and maybe it's also possible to detect interventions simply by observing the changes in these numbers. I'm sure there are also several additional functions that have been incorporated, and that very few people know about, and that are kept secret.'

...detecting interventions based on the change of this number...

No, tuning doesn't change them. That would have come to my attention

I am only familiar with the influence of STG internal errors (RAM, EEPROM, Watchdog, ...).
where I would actually like to exclude this in relation to Alex's cars.

@Alex
What kind of interface do you use?

Hi Rudi

Hello everyone!

The two STGs are still virgins
As an adapter, I use a noname part that I bought from egedöns a long time ago. Unfortunately, I am not familiar with the internal structure.
This is not a particularly high-quality adapter (OBD - RS232), but so far it has at least always worked reliably.

I still find it completely incomprehensible what triggered this change.

One can hardly talk about a break-in period either, as both vehicles have mileage between 160,000 and 170,000 km.

Hmmm: Vielleicht erfolgte der Sprung ja bei 160tkm It's possible the failure occurred around 160,000 km Possibly, a specific parameter range was activated at that point, causing the engine to wear out more quickly, so that people could buy a new car soon Software-based tuning by VAG

Greetings
Alex

But you haven't made any errors

Do you perhaps have made any changes to the adaptation channels (on both cars to the
same type)?

Hi Rudi

@Rudi!

Bingo
That might be it. I have adapted the emissions return rate to the minimum return amount for both vehicles. That could be the cause.

Thanks for the tip, Rudi!

I'm just going to reset to factory settings again to see if there's a connection.

As far as I know, the maximum allowable fresh air mass for AGR/ALH is currently 370mg/h, which is just sufficient to meet the emission standards. If you utilize the range of adaptation, then up to 470mg/h is possible. Possibly, this is indicated by the "40".

Another explanation doesn't come to mind at the moment.

Greetings
Alex

**Dust off**

Okay, I just reset the AGR rate adaptation channel back to the factory settings. Upon the next engine start, the MSG also promptly re-established communication using its usual encoding:

vorher: 038 906 018 A 40SG1001
now: 038 906 018 A 00SG1001

Here, essentially, a marker is being set to indicate adaptations outside the legal area.

Greetings
Alex

It seems there is indeed something to do with the emissions values - perhaps the emissions standard can also be determined from the figures, if there is a connection.