My 2010 1.3 multi air diesel Punto Evo has started to regenerate on a frequent basis with no warning light on the instrument cluster. Lasts about three minutes, (lots of blue smoke) about every couple of weeks even when the engine is not up to temperature. There are no recorded error messages. Local mechanics clueless. Any ideas , anyone ?

It sound to me as a faulty DPF. The dealership can check the ECM, for the stats on the DPF, as how long a regeneration takes, what temps. They have a tendency to go bad once there was petrol in the system.