Nissan Repair: Nissan Pathfinder 2006 Fault code P0039, nissan garage, nissan pathfinder

Question
Hello, the problem I have with this vehicle is when I accelerate hard the vehicle loses power and goes into limp mode, when I turn it off and restart it drives fine.
I have changed the fuel filter and had someone put a diagnostic machine on it and has come up with a fault code of P0039,the local nissan garage has been no help.
Hope you can help, Thank you Simon.  

Answer
Simon,

I will assume you have the turbo or supercharged engine from the code you provided?  If so here is what it is.  There is a pressure sensor on the circuit that determines boost.  If it is out of range, as in too high or low, this will throw a code.  If performance it down it is probably the waste gate.  Check for a faulty hose that is allowing the pressure to leak off.  Email me back and let me know what you find.

P0039 Turbo/Super Charger Bypass Valve Control Circuit Range/Performance