Hello
sorry for my english

Today im trying to flash friend's car (2000, 1.8T AUM 032DR) by KKL cable

nefmoto connects to the ecu, read it and saves it to hdd, im changing it and try to flash, but there was error "connection problem" after "requesting to erase data" or something like this (i didnt save log )

i was trying to select another baud rate but nothing has changed.. and car can only cranking (damn..)

only after swaping his ecu into my car, we can flash it and his car alives

i know that he make an engine swap 1.6 BAD to 1.8T AUM and maybe something bad with harness.

the question is - how can i test the connection without make any changes in firmware to avoid this stupid situation in the future?
thanks
or maybe i need other cable?