Here is the tip to program VW LT28/31/35 1998- transponder key.
Immobox is located left side above the pedals.
Hidden but look for big green connector.
YM15 decode
Read HC05x32 MCU.
Do not read boot but Skip Security Bytes!!
Or else you can erase the memory
Best to use adapter don’t read in circuit.
I read with Orange5.
Generate key with a supported programmer, i.e Tango.