my octavia was fitted with a new turbo before i bought it..and also it was fitted with a dump valve.. my engine light is on and its always been on , it shows up with 3 codes relating to the turbo ..pressure drop..system too rich etc...doesnt effect the performance sometimes the revs drop up and down in idle after ive been on the motorway.... all i want to know is cud it be the dump valve thats creatin the proplem..and shud i take it off?? thx

What engine?

If it's a dump valve then yes. If it's a 1.8T engine then it need a diverter valve, NOT a dump valve