First a thank you to every one that reply to my post and gave input,
I have managed to connect and read the ECU in my fiat siena 1.6 16v
I have used a VAG KKL 409.1 USB interface a 16 to 3 pin connector adapter and multiecuscan SW, in my case the ECU is a magneti marelli IAW 49f, it worked first time, now I need to know what "fuel trim error mean"

It means that the air/fuel mixture is outside the ECU reading.

thank you I gather that much I was hoping for a more specific error, like the lambda sensor, I read somewhere that the ECU don't read the lambda sensor until the car is at normal operating temperature, do you know if is true?