Not sure what scanner you used but cheap ODB2 and "scan any car" scanners can often fail to correctly interrogate the ECU to retrieve the codes.

I'm not entirely sure that's quite true. EOBD (or OBD2 as it's known in North America and Asia) is a standard by which all cars must comply. The manufacturer must allow access to a minimum amount of information and data relating to engine emissions. How much more data they make available or otherwise is entirely at their discretion. All compatible EOBD devices should cover all the protocols to access engine emission data on any compliant car, but they will not be able to access any manufacturer specific engine data or any other module on the vehicle. This is where such devices have their limitations. As long as you're aware of that when you buy one there should be no problem. All compliant vehicles use standard Powertrain (P) fault codes.

It's probably Euro 4 with no DPF. A good dose of injector cleaner and a good hard thrash will most likely get it through.