why dus my engine light show up wen engine warm it shows code 22 knock sensor /but it dusnt show up wen cold /
what wud the symptons be if ran with it gone

 

the knock sensor is bolted to the block under the inlet manifold..

if it has failed then you have no knock control and the ecu will have pulled the ignition back and possibly cut the boost..

or worse the sensor is fine and the engine is making a lot of noise..

Replace the sensor and go from there imho.
also check the wiring and connector look intact

Simon