i have light switch on my S4 so i can turn off light. yesterday had to go change tires. i was trying to red map from ecu but no sucsess. maybe its cable.but the works fine with jpdiag. i understand everything else that you wrote. its wise to have a backup map for ecu
Check the site where you downloaded IAW Diag.
There are instructions for setting up and/or testing connection/connectivity.
A good thing to test is the Device manager for the Com Ports.
It will tell you what device you have.
Hopefully it is the FTDI 232 as this should function well.
If you have the Prolific Chip, something like CH431, which is reported to be common on eBay and Amazon etc. sites, then they can cause problems, which apparently can be solved by soldering a couple of connections in the adapter.
1. Open Control panel.
2. Select System and maintenance
3. Then Hardware and sound
4. Then Device manager
5. Then Ports (COM & LPT)
6. Find the one named USB Serial Port
Then go from there on finding what driver you have.