ECU access algorithm

I have an access problem to ECU's program because ECU requests/asks a question code and I must enter a correct question code which it changes every time. My request is to be solved the answer algorithm. I have programming device that producing the answer codes, So I can supply too many answer codes and question codes. My problem is to be defined the algorihtm. Hexadesimal Samples : ( We can produce question and answer ) 00 00 00 00 / This is question code given by ECU. E9 84 BF 7A / Answer must be given to ECU. 00 B6 3E DE / This is question code given by ECU. A2 50 55 E2 / Answer must be given to ECU. 00 75 EA 07 / This is question code given by ECU. 34 15 EA 74 / Answer must be given to ECU. 00 4B 42 BD / This is question code given by ECU. 4A 5C C0 47 / Answer must be given to ECU. We can send too many other codes and replies.