C4 HDi 1.6 110Hp 2009 - Turbo flutter during regeneration

[devmorfo]

Hello people,

I have this strange issue with my car and I don't know where to start with it. The car runs fine (EGR blanked out 3 years ago), pulls like new and up until recently it used to regenerate just fine. Three regenerations ago it began doing a turbo flutter sound during regeneration only, and even though I can force it to occur by lifting my foot off the pedal, it also occurs going uphill (always during regeneration). I tried to make it flutter when it is not regenerating without success.

I plugged in my OBDII fob and monitor software during the last regen, and I noticed that every time it flutters, turbo pressure output goes down to atmospheric pressure and picks up again, which sounds about right for turbo flutter.

I fail to understand what could make the car close the air throttles during regen ... Could it be that the throttles have gone bad ? how can I test it ? I went to the "dealer" and their response was "turbo is failing, you will soon need a new one" ... but I just don't believe them ...

Anyone with good knowledge of what the ECU is doing during regen that might cause flutter would be of great assistance ... Even previous experiences with turbo flutter on an HDi would be appreciated. I know those engines don't have a blow out valves, so a stuck BOV is not an option.

Help .... !!