communicating with the Arduino adaptor to OBD2 via UART

I am Supposedly writing to this adaptor using uart run at 38400 baud rate, to the ELM327. I am operating this UART with a BlackFin DSP. The protocol is sending "01 0D\" or "01 0C\" - although when simulating this with a PC program, based on .NET it works, when trying to communicate with the ELM327 via Arduino adaptor via UART, I get no answer of any kind to my Rx UART port.

Any ideas that can explain this, as to fix this, or am I missing out something.

Maccabi