Vauxhall Zafira 2003 diesel turbo - vacuum/exhaust gas reg valve error?

after finding this site on a search 'punt' found someone elses similiar turbo probs in 2010 - have changed the sensor for about £55 but still getting engine warning light (yellow dash icon - car with spanner in it) - got an exhaust gas error code which I have been told is lack of pressure to turbo. Car was driveable and able to 'limp' upto 70 on a flat road but no oomph or revs over 2800 ish, now got a lot of smoke and virtually no power ! hoses to turbo seem ok but been advised a cracked pipe coming out of solenoid and into hose could be a likely suspect ? not sure where this is tho - any help ?