RFERG43

I have an ELM 322 scanner and Scantool software (beta version) to read DTCs from my PCU but it will not read the VIN. I can read DTCs by manually sending the commands using Hyperterm but when I send the command "0902", which according "manual" I got with the ELM is supposed to return the VIN, "no data" is returned. Can anyone shed any light on this?