i have a vauxhall zafira 2.0dti. the turbo kicks in every 8 months or so. ?

My vauxhall zafira 2.0 dti turbo kicks in sporadically. Recently had a service and it has been running ok I suppose. Before the service, I had loss of power constantly. Now, a light keeps coming on the dash in the shape of a fuel tank, with a star in it. Total loss of power thereafter. The rev counter shows no rpm and the engine starts "hunting". Recently cleaned egr valve and checked all pipes and intercooler. Can't seem to see anything. What can it be?