ive run into an identical situation with a vp v6. bought the setup off ebay and having trouble communicating with the car. ive noticed that when i tried to do a self diagnosis by bridging the 2 end wires my check engine light didnt blink at all but the radiator fan did come on. could it be as simple as the check engine bulb on the dash playing up? it seems to be on when i turn the key to the reds, and sometimes not.... hmmmm