How to solve VVDI2 Golf 5 2005 K-Line Not Working Error
Problem:
Hi, I have with Xhorse vvdi2 vag v5.5.0 problems with edc16u1 ecu and dashboard.
It can’t read golf 5 2005 year. Something not ok with it
It looks like K line not working.
picture attached:
Error “Can’t connect to device. Switch ignition OFF/ON and retry”
Error “Non-standard upload data failed”
Solved!!!
Here’s the customer solution:
I test it this morning and all works fine now.
I removed soldering ball and i reinstall drivers and all working fine.
It reads now over kline it detects edc16 ecus and it read immo data eeprom and also dashboard it can read now.
I check k line from vvdi2 db25 connector on PCB to the optocupler (relay) omron, and from it to the ADG1606B multiplexer then from multiplexer to the L9637 interface. Then from it to the mcu Rx and TX line. All is ok. Even replace from vvdi 1 L9637 ISO 9141 interface. Didn’t work. Then I measured supply to the omron optocoupler relay it has 1.2 v when activate Kline communication. Check also 120ohm pull down resistors, check supply to the multiplexer ADG1606B it is ok 3.3v ako also on iso 9141(L9637) interface, and also I have on oscilloscope TX and TX signals from mcu to the L9637 it send data when It activate Kline. And in the end I found one solder ball between legs of multiplexer. You can see it on picture that I send you before. First time i open it. That was the main problem and USB drivers.
this is all i tested on this interface. Now all is fine and i can work now 
Interface is very high quality production, but this is something that happens from time to time.
Hope this helps.