Thanks for the info Steve !
So we have a kind of built-in acceptance filter in the Pico; I did not know that.
@ Belet: OBD2 communication is mostly between DiagTool and Engine ECU.
Therefore, it is best to search for the identifier 7E8 (= engine ECU - only valid forb OBD2, not for
internal communication with other ECU's).
Please do understand that OBD2 is query - reply based. The diag tool (scanner) wil send queries (ID = 7DF) and receives replies (ID = 7E8). You will see both ID's on the bus while reading the "live data".