Consult is the software not the protocol.
ODBII uses one of 5 protocols.
SAE J1850 PWM
SAE J1850 VPW
ISO 9141-2.
ISO 14230
ISO 15765 CAN
There is no required protocol however all cars since about 95 or something must use one of them. There is differences in the sockets and they can be told apart but I'm not going into that much detail, if people want to find it they can use Google.
But most newer ECU readers don't work in models before 06, however it also depends on the protocols the reader can handle, so the short answer is maybe/maybe not