Question: is there a way to tell/determine if the gearbox is a cxx, exx, fxx or mqb version DQ250?
Every gearbox can have any type of mechatronics tucked in, even by mistake.
So, looking on gearbox (code) will not give you sure that inside is Cxx or Exx or other.
The only way to recognize it is hardware number of the TCM.
Here some informations about 02E Hardware Numbers assignment:
GROUP “Cxx” EARLY UNITS all with analog inputs (for speed signal, shift paddles or reverse light control) (used moslty 2003-2004 some of them have additional pins in connector)
02E927770 E
02E927770 G
02E927770 K
02E927770 L
02E927770 M
02E927770 AA
GROUP “Cxx” (2004 – 2006)
02E927770 AD – replaces all EARLY analog units because can EMULATE analog inputs.
02E927770 AE – used only on cars from year 2004 which DO NOT use analog signals anymore.
GROUP “Exx” (2007 – 2008)
02E927770 AJ – used as replacement for AE, CAN only, no K-Line anymore.
02E927770 AK – no information nor experiences til now. Very rare unit.
GROUP “Fxx” (2008 – 2015)
02E927770 AL – replacement for AE, AJ
02E927770 AM – theoretically can be used on some cars which still needs AD, but special software versions are required.
02E927770 AT – replace AL
IMMOBILIZED UNITS used on MQB cars with UDS diagnostic protocol.
Cannot replace NON-IMMO units, because of bootloader incompatibility.
02E927770 AN
02E927770 AQ
02E927770 AS
you can swap fxx and cxx as long as you use fxx firmware on fxx and cxx on cxx.