KESS V2 is an ECU programming tool that is perfect for OBD use, while KTag is perfect for Jtag, BDM and all the Boot application (tricore and ST10).
With KESS V2 you programming directly through the OBD port of the vehicle, while with Ktag you need to take apart the ECU and open it, after you can make the read/write operation.
Many ECU has the advantage that can be read and write from OBD port (so KESS V2 is perfect), but there are lot ECU that need to disassemble from the car and open and this is the case for all the ECU that need to be programmed with Jtag, BDM and Boot protocols, so KTAG is needed.
Fgtech V54 works with cars, trucks and motorcycles, it read write ECU via BDM and OBD.
Personally, I prefer kess V2 and fgtech v54.
I have one good seller to recommend you.
kess V2 V2.15:
Others prefer (feedback):
A. Kess is for OBD, it is very good tool, KTAG is for BDM/JTAG/BOOT
Alientech devices are good. Personally i would choose KESS and KTAG.
B. I have both and prefer CMD
but if you are gonna make tunings for Trucks I prefer KessV2.
Its like beauty it changes person to person. Kess has much more OBD connection beside CMD but CMD is hardcore on OBD, it has recovery chance.
C. I have china clone K-TAG and KESSv2 both v1.89. Not latest version, but it working for me. I test my K-TAG on TPROT 8/10 ECU, read/write ok, checksumm too.
This master set costs 700$ for me :-)
As for newer ECU EDC17 - it seems tprot >10 there, so even original K-TAG can't do it yet.
D. CMD everytime, Its the most stable and quickest. Also doesnt wear out ignition barrells with key on/off/on/off/on/off/on like the kess.