Go to the Google Play store and search for Torque pro. the Torque description page gives advice on bluetooth adaptors. Torque Pro is about £3 and I paid about £20 for an adaptor. It works very well and is worth having for the cost. However, it may not help you because it only reads what's in your ecu, which may not be storing a fault code for the fault you are experiencing.

My Saab 9-3 petrol runs like a bag of spanners from cold for about 15 seconds and then smooths out. the usual cause is worn inlet valves. A cold followed by a hot compression test is required to confirm. I'm waiting the delivery of a new compression tester - old faithful has gone walkabout. i'm also buying a cheap endoscope so i can look at the valves via the plug holes.

this is a common problem on these engines built in 2006 and 2007 and is caused by a metalurgical problem with the valve material. Only inlet valves are affected.

if your problem is similarly mechanical in nature, then you will get no fault code in the ECU (as I do not either).

No codes doesn't mean no faults,

It means all sensor data is within manufacturers limits.

So no scanner is going to be any help.

Though Renaults "Can clip" would be my choice.

A good tech would be able to read live data stream information and have a better idea of just what it's doing.

But sometimes its back to basic mechanics,

that said I'd start with a cold engine compression test.