VW Passat 1998 1.9 TDI AFN ECU repair

[art64]

Hello,DK friends,
I had starting problems with VW Passat 1998y 1.9 TDI AFN,
ECU-BOSCH 0 281 001 720,VW 038 906 018.
The engine was starting for a moment and did turn off in the second moment
(like immobilizer problem).Some times a car was starting normally. But a dash didn't
have DTC linking to the imobilizer and the engine's ECU was not responding
to the diagnostics request.I decided what the problem is in the engine's ECU,
changed it with other one second hand ECU and everything is OK,a car is running.
But I would like to restore the old ECU. I resoldered the ECU's points marked in
the second picture in red color.But without success:ECU still not communicating with dash
and not responding to the diagnostics request.Do anybody know which chip in the
pictures is responsible for communication with dash? Please,mark this on the picture.
Thank you

[ominimicu]

First picture one of the 3 to the left that are identical, dunno which but there is where k line com lies

[art64]

First picture one of the 3 to the left that are identical, dunno which but there is where k line com lies

I think,it's necessary W line for me,not K. ECU linking to diagnostics equipment via dash,not directly through K

[veloseeped]

First picture one of the 3 to the left that are identical, dunno which but there is where k line com lies

Wrong hint - this chips have nothing common to K-line communication

art64, K-line and and W-line is the same from ECU point of view.
During diag sesson dash acts as simple switch - connect W to K through relay.
See the picture. Marked 30377 chip has inside ISO9141 driver.
Signal goes through this driver direct to main C166 CPU.
199868

[art64]

Big thanks for you,veloseeped,
So,if chip 30377 and CPU is good has grounds,sources and K line,it must work (communicate)? And what is mask of CPU? (which chip is CPU) :"siemens..." or next,this biggest one?