YES - cleared the light finally.
I ended up using a cable known to have the FTDI chips in and the program Trw2Scan. (Just like Barney said
For anyone interested here are a few things I found on the way. (Additional info and credit from this THREAD
and this THREAD
No claim to originality on my part , everything is a distillation of whats already out there. )
There appear to be four different airbag ECUs used on the Coupe. There was an early one from Becker. That is the one that has three wires to the diag socket and can be interrogated and reset by grounding one of the leads. The others 3 have two wires to the diag socket and were from TRW:
46306560 - A TRW2 type. Can be reset with TRW2SCAN.
46306172 and 46316266 - MY97 types. Can be reset with multiecuscan (or fiatecuscan).
Mine was a TRW2 type (it had 46306560 printed on its barcode.) So I can only comment on that from here on in.
Cables :- There are typically 3 types of KKL VAG OBD cables sold on ebay and as mentioned elsewhere you will also need the 3 pin Fiat adapter.
Cable 1 is a bog standard KKL/VAG/OBD . It will require CH340 serial drivers and WILL NOT work with Trw2scan. It will however give intermittent connections to the engine ecu using startrek and multiecuscan.
Cable 2 is the same as the above but has a 4 way switch incorporated into the body of the connector. I'm still waiting for delivery on this item.
Cable 3 is a KKL/VAG/OBD cable with the FTDI chipset. This is the cable that works "out the box" with Startrek / Multiecuscan and Trw2scan.
You can read all about the different programs on that link to the alfa forum given above but if you have the TRW2 airbag you will need to download the TRW2 program from HERE
and the FTDI drivers from HERE
Note on Trw2scan : This is specifically for a TRW2 Airbag ECU which is found on some of the early cars and has TRW part number 60631206 printed on it's label (or 60625181 for the GTV 916 Phase 1). This model of Airbag ECU cannot be diagnosed or reset by any other DIY software available on the market.
If you have read earlier parts of this thread you can see I mentioned the dire warnings given by MultiEcuScan before attempting to connect to this type of ecu. Well the documentation for Trw2Scan gives the same dire warning but the program itself does not. So unless you read the documentation first you wouldn't see the warning. But then again its the only program that will work with the ecu so what choice do you have ???? Do as I did. DON'T sit in the car whilst connecting to the ecu.
Anyway once you have the right cable/software and driver then for this TRW2 type ecu simply run the program , (you must have the ignition on) it will connect and if it finds any errors it will report them and then ask if you want to reset the ecu. Just answer yes at which point the program will attempt to reset the warning light and exit.
Once the program exits the airbag warning light on the dashboard will still be lit. You have to switch the ignition off and back on for the light to clear. (Give it a few seconds as per usual)
The frustrating thing is that all the right info is on the forum but it took me so long and so much trial and error to sort it.
Thanks to the forum