my friend has a 1999 b4 legacy and the first stage turbo is slow to respond sometimes none exixstant.
the fault codes coming up are 22 knock sensor, 65 differential pressure, 66 two stage twin turbo system, 66 twin turbo systems.
has anyone come across this before?
thanks

 

Check all vacume hoses ,and all other hoses ,on mine it was hoses leaking if you get a can of EASY start and spray it around hoses it will rev up on its own ,the knock sensor is fun to get to its under manifols at thr back near bellhousing 12mm