Hi Shaun not simply a seized turbo is it? no boost pressure? remove intake pipe & check if the turbo spins. We just recently had the same on a Renault, could'nt make out why MAP readings went below 1000 mb when reved. Boost pressure should be well above 1000 mb, these problems catch us out when there can sometimes be a simple mechanical failure making the data look funny. John Kennard.