Whistling the blues?

I have a 2012 Volkswagen Passat 1.6 Bluemotion. The glow plug light is coming on and the car goes into ‘limp-home’ mode. I replaced the EGR, which was not holding vacuum, with a new Intermotor complete unit, but it didn’t help. The car also acquired an induction whine at 2000rpm – there is a whistling noise, which might be an air leak. The fault codes that showed up are: Air pressure sensor 1 Rail fuel pressure sensor Fuel system Bank 1 Boost pressure sensor The particulate filter might need to be regenerated, but I’m not sure. I have erased the fault codes and everything seems to be fine, apart from the screech at 2000rpm, which I thought I had cured after tightening two slack Jubilee clips. Colm I suspect you had an air leak to the inlet system, which you have partly cured by tightening the clips. If you still have a whistle at 2000rpm, there’s still an inlet air leak, made more audible because 2000rpm is when the turbo kicks in. Visual inspection is your first port of call. If this fails, identifying the source of the leak is best done with a smoke generator feed into the inlet system. Other methods are to use an ultrasonic transmitter and detector, and spraying a combustible liquid around suspected leaks while observing the engine RPM.