ECUHELP KT200II ECU Programmer is confirmed to read/write JD Phoenix L33 via OBD, also do the checksum ok.
KT200II Write JD Phoenix L33 via OBD-01

Also KT200II read/write JD Phoenix L33 Pinout mode:
To connect to the control unit use:
– Multifunction cable
KT200II connect PHOENIX L21/22/23/33/34 - John Deere [Diesel]