Arduino and ODB2 with car (ODBuino32K project)

Dear forum users,

hope somebody have some experiences with Arduino and ODB2 car communication. I am using OBDuino32K project code ( ) and try to connect Arduino and car through ODB2.

Description: Arduino Uno, MC33290 chip (from eBay), Arduino LCD shield with buttons (also from eBay), car with ODB2 connector (VW Passat 1.9 TDI, production year 1998 from Europe). All parts are connected in order with this scheme: But without any button connections and without DB9M connector (I directly used three wires and connected them to the ODB2 female connector on the car: ground, ISO K and power wires on pins described here: )

Unfortunately, I stuck at the initialization phase. I use OBDuino32K code (version 198) and I suspect that problem occurs in the void iso_ini(). I receive '0x55' value from car (which is OK) and then '0x08' values for kw1 and kw2 (which is also OK). But after the command iso_write_byte(~b) car response is not as expected (b values is not '0xCC' but '0x55'). I am not sure how to check if car really receive '~b' value (if command iso_write_byte(~b) is successful) and why response from car is not '0xCC'. So this is the point where I stuck.

Hope you have some suggestions, thanks and kind regards, Rok