App for OBD2 fault scanning - Ford Fiesta

[catso]

My Son has a 2014 Fiesta 1.25 that has a an occasional 'Engine Service Now' warning appear on the display, it doesn't stay on just flashes on then off. It's not a service due warning, rather a fault warning of something although no CEL on and car drives fine, a quick google suggests various possibilities; sensors, catalytic converter etc.

I have an OBDII wifi scan tool that I have previously used on his old car (Renault Clio) using the 'Carista' app, however the app seems to have changed dramatically since then and I can't get to to work, at least not with the Ford.

Assuming the tool is still working, can anyone recommend a good app (preferably free) that will communicate with the OBD and therefore the car to see if I can find whatever is causing the warning?

TIA

[lemonslap]

Forscan is my go to tool for my fiesta, always used their laptop based software but I believe they have an app.

[catso]

Thanks, will give it a try.