Help with my friends GTI
 

His GTI is a 2002, 5spd

Mods:
EIP ecu
EIP turbo back
EIP Cold air intake
Forge DV

He's throwing this code:

17705-pressure drop btwn turbo and throttle valve (check d.v.)

We have checked the DV, it's fine. What else to look for?

boost leak? intercooler leaking?

Okay, I was thinking on the same line.
 

We'll have to do a pressure test.

Thanks.