JDM D15B motor swap help

I recently finished a JDM D15B VTEC motor swap. The car was a Civic DX automatic. The car runs like a dream but is missing a connector for the VSS (Vehicle Speed Sensor) and I am getting "Check Engine Light." The engine was set up for manual but since I couldn't afford the tranny, I just kept on the automatic tranny. I have a p28 ECU. Do I need another harness or is the Check Engine Light from something else??

Check to see what code your ecu is flashing