Dear toc,
today I check more precisely response from the car. All values are in HEX format, ~ means inverse operation.
After initial procedure (sending 33 at 5 bauds) I receive 55 from car and iso_read_byte() returns true. Then I receive 08 (iso_read_byte() returns true) and again 08 (iso_read_byte() returns true). Then Arduino send ~08 to the car (with iso_write_byte() method). After this, car does not respond (iso_read_byte() returns false 'forever').
So I presume that:
1) iso_write_byte() method does not send anything (Is it possible to check (i.e. with voltmeter) if there is some activity on K line when iso_write_byte() method is active? How?).
2) Car is waiting for some other value from Arduino. Which?
Do you have some suggestions?
Maybe this will help: I also connect to the car (VW Passat, 1.9 TDI, 1998) with VAG-COM program (ODB-II compatibility test in the program). Result:
Protocol keyword: $0808, ISO9142-2 ODB-II compatible.
Many thanks and regards,
Rok