I know that turbos need load to produce boost and if you clutch is gone enough then it wont produce any. Get that fixed before looking at your turbos.
But if you can take the piping off and inspect them, looking for shaft play or other signs of wear (teeth missing, wear on compressor housing). This wont tell you if the wheel has fallen off the turbine though (pretty sure they are ceramic so someone correct me if im wrong while i look it up).
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