If we had a dollar for every time we got this question, we'd be retired by now and living on some tropical island.

So why do we get this question so often? Because there are exactly one bazillion different reasons why you might not be able to connect the application running on your laptop to the chip inside your ECU. Between those two end points there are device drivers, USB ports, our diagnostic cable, the diagnostic port (& pins) inside your car, wiring between that port and the ECU, other things attached to those wires in your car and then circuitry inside the ECU and even power being provided to the ECU and ground on the diagnostic port.

Over the years we have seen every single one of those things go bad in someone's random 20+ year-old car. The most memorable of which was one guy we went back and forth with for 20+ e-mails until he finally realized that one of the pins in his car's diagnostic port was actually loose and pushing out of the way when he plugged his cable in! So it looked fine and tested fine without the cable plugged in but once the cable was inserted, the pin failed to make contact because it was simply not beign held in position.

So there is absolutely no single answer we can give to that question. And it's difficult to even write up a complete troubleshooting guide because there are just so many different ways that any one of those things might be bad.

That said, here's an attempt to provide some sort of “debugging” flow chart to help.

<Place holder> - I'll work on this, I promise. But I wanted to get the page started as my reminder.