Engine Control Unit (ECU) Coding 0002/0012

Passat 3B TDI, manufactured in 1999, engine code AJM - the engine control unit (ECU) is coded with 0002. A colleague has the same car, but their ECU is coded with 0012. Both vehicles are identical, with manual transmissions and the same equipment. Does the coding of 0012 instead of 0002 offer any advantages, or is it related to the country where the vehicle is operated? My car is from Germany, and my colleague's car is from Switzerland.

hb2000 wrote:

Does the coding with 0012 instead of 0002 offer an advantage, or does it depend on the country where the vehicle is operated? My vehicle is from Germany, and my colleague's vehicle is from Switzerland.

AFAIK, the performance-relevant primary parameter fields (torque, driver request, injection start, boost pressure, etc.) of the coding never differ within the same MSG.
Do you also have the same MSG?

The coding for AJM is as follows:

00001 - automatisches Getriebe
00002 - Schaltgetriebe
00012 - Schaltgetriebe mit Kundendienstlösung (unrunder Leerlauf/Beschleunigungsloch)
00003 - Allrad mit ESP
00005 - Allrad ohne ESP

So, the code 0012 is a workshop solution when a customer complains about an unstable idle. This means that whoever programmed the calibration maps must have already been aware of a problem with the idle. It would be interesting to know what the differences are between the various codes and which data sets are relevant. How do you achieve a stable idle, or what compromises are acceptable?

The question is whether there are other coding possibilities for the AJM engine, or if these are the only combinations that are currently known. In our SKODA Fabia, manufactured in 2000, the engine control unit is coded with '0071' - so it seems there are also codes that fall outside the range of 0000 to 0010. Perhaps there are also certain service codes for the AJM engine, the existence of which is not yet known.

In our SKODA Fabia, manufactured in 2000, the engine control unit is coded with 0071 - so it seems there are codes that fall outside the range of 0000 to 0010.

What is the engine code of your Fabia?

This coding for the Fabia simply indicates that there are other engine management systems available.
'which are encoded differently; if needed, I can gladly provide you with a table for the Fabia.'

Perhaps there are also certain service codes for the AJM.
of which the existence was, until now, unknown.

The list posted above contains the information currently known to VAG.

Regarding the Fabia, I still need to check the engine control unit (ECU) more closely. Initially, the control module was coded differently, with a code below 0010. It was only after we had problems with various control units that someone at the dealership entered this code, and since then, everything has been stable. This whole mess was actually caused by a Sony radio that was incorrectly installed by the dealership. If I hadn't had my laptop with Vag-Com back then, they would have charged me the entire damage amount of 1500 euros. Fortunately, I was able to prove and document that all the errors occurred and that the radio was installed by the dealership. That's why I suspect that the code 0071 is also likely a workaround code.

Well, it would be interesting to know, so please try to find out the engine code letters.
or, alternatively, the part number of the control unit, which would be my preferred option.