DB9 question
 

Is it possible for the serial port on the MS to not work, and the MS to work perfectly fine??I have bought a new serial to usb connector, I think mine died, I'm fairly sure that the reason it doesn't work, just an idea... hence the question at hand..... Thoughts?? Idea's comments??

Usually, the problem is not the serial port but the USB converter, but it is perfectly possible that U6 (MAX232) died. I've had a problem with failing serial and it turned out a bad ground trace to the chip, so measure all the traces out.
If you want to be sure, replace U6, they're cheap.

Yes. The RS-232 driver chip (U6 / MAX232) is separate from the CPU and not required for normal operation of the ECU. You could remove it from the board and the engine would run fine. I can't imagine how you'd cause one to fail, just giving you a direct answer.